Annotation of freem/doc/freem.texi, revision 1.54
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3: @setfilename freem.info
4: @settitle The FreeM Manual
5:
6: @copying
1.54 ! snw 7: This manual is for FreeM, (version 0.64.0), which is a free software implementation of the M programming language.
1.1 snw 8:
1.39 snw 9: Print-optimized versions of this book are typeset in @emph{Computer Modern} by the author using the @emph{GNU Texinfo} tools.
1.1 snw 10:
1.5 snw 11: Copyright @copyright{} 2014-2025 Coherent Logic Development LLC
1.1 snw 12:
13: @quotation
14: Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover texts, and with no Back-Cover Texts.
15: @end quotation
16: @end copying
17:
18: @titlepage
19:
20: @title The FreeM Manual
21: @subtitle @sc{The Official Manual of FreeM}
1.54 ! snw 22: @subtitle Version 0.64.0
1.1 snw 23: @c@vskip 10pt
24: @c@center @image{freem-logo-sm,,,,.png}
25: @author Serena Willis
26: @page
27: @vskip 0pt plus 1filll
28: @insertcopying
29: @end titlepage
30: @contents
31:
32: @ifnottex
33: @node Top
34: @top The FreeM Manual
35:
36: This is the official manual for the FreeM programming language.
37: @end ifnottex
38:
39: @dircategory The FreeM Manual
40: @direntry
41: * FreeM: (freem). The FreeM M programming language.
42: @end direntry
43:
44: @menu
45: * Introduction:: About the FreeM Project, its history, and its goals.
1.36 snw 46: * Document Conventions:: Conventions used in this manual.
1.39 snw 47: * A Note on Standards:: FreeM positioning regarding the M Development Committee.
1.1 snw 48: * FreeM Invocation:: How to invoke FreeM from the command line.
1.22 snw 49: * The FreeM Environment Daemon:: Managing shared resources in the FreeM environment.
1.1 snw 50: * The FreeM Direct-Mode Environment:: Executing M programs interactively.
1.36 snw 51: * Debugging:: The program development cycle of FreeM.
1.1 snw 52:
53: * Directives:: Per-Routine Language Directives.
54: * Intrinsic Special Variables:: Intrinsic Special Variables.
55: * Intrinsic Functions:: Intrinsic Functions.
56: * OBJECT Methods:: Methods for OBJECT variables.
57: * STRING Methods:: Methods for STRING variables.
58: * Commands:: Commands.
59: * Structured System Variables:: Structured System Variables.
60: * Operators:: FreeM Operators.
61:
62: * Routines:: The units of M code in FreeM.
63: * Types:: FreeM data types.
64: * Globals:: FreeM persistent sparse arrays.
65: * Concurrency Control:: @code{LOCK}ing and transaction processing.
66: * Local Variables:: In-memory variables.
67: * Scoping:: Scoping in FreeM.
68: * Decision Constructs:: @code{IF}, @code{THEN}, @code{ELSE}, @code{$SELECT}, and postconditionals.
69: * Branch Constructs:: Labels, @code{GOTO}, @code{DO}, and @code{JOB}.
70: * Loop Constructs:: The @code{FOR} loop.
71: * Modular Programming:: Extrinsic functions and subroutines.
72: * Object-Oriented Programming:: Classes and objects in FreeM.
73: * Libraries:: System and user libraries.
74: * Sequential I/O:: Processing sequential files in FreeM.
75: * Network I/O:: Handling network sockets in FreeM.
76: * Extended Global References:: Accessing globals in non-default namespaces.
77: * Global Aliasing:: Defining alternate names for globals.
78: * Global Mappings:: Mapping global names to non-default namespaces.
79:
80: * Asynchronous Event Handling:: Handling asynchronous events in FreeM.
81: * Global Triggers:: Responding to global accesses in M code.
82: * Synchronous Event Handling:: Synchronous events in FreeM.
83:
84:
85: * GUI Programming with MWAPI:: Creating graphical interfaces in FreeM.
86:
87: * User-Defined Z Commands:: Adding your own Z commands to FreeM.
88: * User-Defined Z Functions:: Adding your own Z functions to FreeM.
89: * User-Defined SSVNs:: Adding your own SSVNs to FreeM.
90:
91: * Language Dialects:: Controlling FreeM standards compliance.
92:
93: * System Library Routines:: FreeM built-in library of M routines.
94:
95: * Interrupt Handling:: How FreeM handles interrupts.
96: * Error Processing:: How to handle errors in M program code.
97: * FreeM Error Codes:: Explanations of each FreeM error code.
98:
99: * System Configuration:: Configuring your FreeM installation.
100: * Accessing FreeM from C Programs:: How to use the mlib interface.
101:
102: * FreeM Administrator:: The fmadm system manager tool.
103: * FreeM VIEW Commands and Functions:: Getting and setting info about FreeM internals.
104: * Implementation Limits:: FreeM limitations.
105: * US-ASCII Character Set:: The US-ASCII character set.
106: * FreeM Project Coding Standards:: How to write code for submission to the FreeM project.
107:
108: * Index:: Complete index.
109: @end menu
110:
111: @node Introduction
112: @unnumbered Introduction
113:
1.36 snw 114: FreeM started its life as @emph{FreeMUMPS}, written for MS-DOS and ported to SCO UNIX by a mysterious individual going by the name of "Shalom ha-Ashkenaz". It was released to MUG Deutschland in 1998. In 1999, Ronald L. Fox ported FreeM to the Red Hat Linux 5 distribution of the GNU/Linux operating system. Thereafter, maintenance was taken over by the Generic Universal M Project, which changed its name first to Public Standard MUMPS and then by popular request to FreeM.
1.1 snw 115:
116: When GT.M was open-sourced in late 1999, FreeM and GUMP were essentially abandoned. L.D. Landis, the owner of the original GUMP SourceForge project, and one of FreeM's significant contributors, passed maintenance of FreeM and ownership of its SourceForge project to Serena Willis in 2014. At this point, FreeM would not compile or run on modern Linux systems, so steps were taken to remedy the most pressing issues in the codebase. Limitations on the terminal size (previously hard-coded to 80x25) were lifted, and new @code{$VIEW} functions were added to retrieve the terminal size information. @code{$X} and @code{$Y} intrinsic special variables were updated to support arbitrary terminal sizes, and FreeM was once again able to build and run.
117:
1.36 snw 118: In February of 2020, work began in earnest to build a development and support infrastructure for FreeM and begin the careful process of refining it into a more stable and robust application.
1.1 snw 119:
1.39 snw 120: For more information on FreeM history, see @code{@emph{$PREFIX}/share/freem/doc/freem_history.*} (distributed in PostScript, PDF, and plain text formats).
121:
1.1 snw 122: @section Production Readiness
123:
124: FreeM is not yet production-ready. There are several show-stopping bugs that preclude a general release for public use:
125:
126: @itemize @bullet
127:
128: @item
129: @code{@ref{VIEW}} commands and @code{@ref{$VIEW()}} functions are used extensively to configure and inspect the run-time behavior of FreeM, rather than the "canonical" SSVN-based approach.
130:
131: @item
132: Server sockets are not yet implemented.
133:
134: @item
135: There are some situations that can result in segmentation faults and/or lock-ups.
136:
137: @item
138: In spite of our best efforts, this manual is not yet complete.
139:
140: @end itemize
141:
142: @section Contributors
143: Current contributors denoted with a @emph{+} following their name and role.
144: @cindex contributors, ha-Ashkenaz, Shalom
145: @cindex contributors, Best, John
146: @cindex contributors, Diamond, Jon
147: @cindex contributors, Fox, Ronald L.
148: @cindex contributors, Gerum, Winfried
149: @cindex contributors, Kreis, Greg
150: @cindex contributors, Landis, Larry
151: @cindex contributors, Milligan, Lloyd
152: @cindex contributors, Morris, Steve
153: @cindex contributors, Murray, John
154: @cindex contributors, Pastoors, Wilhelm
155: @cindex contributors, Schell, Kate
156: @cindex contributors, Schofield, Lyle
157: @cindex contributors, Stefanik, Jim
158: @cindex contributors, Trocha, Axel
159: @cindex contributors, Walters, Dick
160: @cindex contributors, Whitten, David
161: @cindex contributors, Wicksell, David
162: @cindex contributors, Willis, Serena
163: @cindex contributors, Zeck, Steve
164:
165: @itemize @bullet
166:
167: @item
168: Shalom ha-Ashkenaz (Original Implementer)
169:
170: @item
171: John Best (IBM i and OS/400)
172:
173: @item
174: Jon Diamond (Library, Utilities, Conformance)
175:
176: @item
177: Ronald L. Fox (Initial port to Red Hat 5/libc-6)
178:
179: @item
180: Winfried Gerum (Code, Advice, MTA coordination)
181:
182: @item
183: Greg Kreis (Hardhats coordination, Dependencies)
184:
185: @item
186: Larry Landis (Coordination, Code, Documentation)
187:
188: @item
189: Rick Marshall (Testing, MDC Conformance) @emph{+}
190:
191: @item
192: Lloyd Milligan (Code, Testing, Documentation)
193:
194: @item
195: Steve Morris (Code, Microsoft)
196:
197: @item
198: John Murray (Code, Conformance)
199:
200: @item
201: Wilhelm Pastoors (Testing, Documentation)
202:
203: @item
204: Kate Schell (Coordination, Conformance, MTA, MDC, Advice)
205:
206: @item
207: Lyle Schofield (Advice, Prioritization, Tracking, Project Management)
208:
209: @item
210: Jim Stefanik (GNU/Linux on s390x, IBM AIX, IBM z/OS)
211:
212: @item
213: Axel Trocha (Code, Utilities)
214:
215: @item
216: Dick Walters (Project Lead, Chief Coordinator, MTA)
217:
218: @item
219: David Whitten (QA Test Suite, MDC, Advice) @emph{+}
220:
221: @item
222: David Wicksell (Debugging, Code, Testing) @emph{+}
223:
224: @item
225: Serena Willis (Current Maintainer and Project Lead) @emph{+}
226:
227: @item
228: Steve Zeck (Code)
229:
230: @end itemize
1.36 snw 231:
232: @node Document Conventions
233: @chapter Document Conventions
234: @cindex document conventions
235: @cindex conventions
236:
237: @section Formatting Conventions
238:
239: This manual uses the following formatting conventions:
240: @itemize
241: @item Code examples, filesystem paths, and commands are presented in @code{monospace}
242: @item Placeholders where the reader is expected to supply a replacement value are presented in @code{@emph{monospace italics}}, and depending on context, may be surrounded by angle brackets
243: @item New terminology is introduced in @emph{proportional italics}
244: @end itemize
245:
246: @section Definitions
247:
248: FreeM uses abbreviations for common language elements:
249:
250: @table @asis
251: @item @emph{$PREFIX}
252: Refers to the base filesystem location within which FreeM is installed. For most distribution methods of FreeM, @emph{$PREFIX} represents either @code{/} or @code{/usr/local}.
1.37 snw 253: @item @emph{dlabel}
254: Refers to a label in an M routine, beginning in the first column of the line. Can be a @emph{name} or an @emph{intlit}.
255: @item @emph{entryref}
256: Refers to an M routine entry point, denoted in the format @code{@emph{dlabel} [+@emph{intexpr}][^@emph{routine}]}.
1.36 snw 257: @item @emph{expr}
258: Refers to any expression. Often presented in the format @emph{expr V <type>}, where @emph{V} means @emph{giving}; e.g., @emph{expr V lvn} means @emph{expression giving local variable name}.
259: @item @emph{glvn}
260: Refers to the name of an M global, local, or structured system variable.
261: @item @emph{gvn}
262: Refers to the name of an M global variable.
263: @item @emph{intexpr}
264: Refers to an integer expression.
1.37 snw 265: @item @emph{intlit}
266: Refers to an integer literal.
1.36 snw 267: @item @emph{ISV}, @emph{isv}
268: Refers to an M intrinsic special variable; @code{$JOB} and @code{$IO} are examples of ISVs.
269: @item @emph{L}
270: Indicates a @emph{list} of the following item, e.g., @emph{L gvn} means @emph{list of global variable names}.
271: @item @emph{lvn}
272: Refers to the name of an M local variable.
1.47 snw 273: @item @emph{postcondition}
274: A @emph{tvexpr} immediately following a command verb affecting that command's execution.
1.37 snw 275: @item @emph{strlit}
276: Refers to an M string literal.
1.36 snw 277: @item @emph{ssvn}
278: Refers to the name of an M structured system variable.
279: @item @emph{tvexpr}
1.47 snw 280: Refers to a truth-valued expression, i.e., an expression interpreted as a truth value.
1.36 snw 281: @end table
282:
1.39 snw 283: @node A Note on Standards
284: @chapter A Note on Standards
285: @cindex MDC
286: @cindex M Development Committee
287: @cindex ANSI X11.1
288: @cindex standards, ANSI
289: @cindex standards, MDC
290:
291: FreeM attempts to implement as many features as possible from the M Development Committee's unpublished @emph{Millennium Draft Standard}, as well as its predecessors.
292:
293: The maintainer of FreeM (who is also the author of this book) is largely in favor of standardization efforts, and hopes that the MDC will resume activities, and will happily participate if it does so in an open, public, transparent, and democratic manner. Until then, however, FreeM will attempt to improve the M language, in cooperation with other free software M implementers where possible. Any breaking changes introduced in future MDC releases of the @emph{Standard} (such as the rumored @emph{M5}) which prove incompatible with FreeM will be handled via the @code{$DIALECT} special variable (to be changed to @code{$ZDIALECT} in a coming release).
294:
295: The conformance document required per the @emph{Standard} should be installed as a @code{man} page on any computer system where FreeM is made available. Simply type @code{man freem_conformance} to access.
296:
1.1 snw 297: @node FreeM Invocation
298: @chapter FreeM Invocation
299: @cindex invocation, command-line
300: @cindex options, command-line
301:
302: @section Synopsis
303: @example
304: $ @command{./freem} [@emph{OPTIONS}...] [[-r <entryref>] | [--routine=<entryref>]]
305: @end example
306:
1.28 snw 307: When FreeM loads, it searches the @code{SYSTEM} namespace for the @code{%SYSINIT} routine, and begins executing it.
1.1 snw 308:
1.28 snw 309: When @code{-r} or @code{--routine} are passed on the command line, FreeM will load and run the specified routine after running @code{%SYSINIT}. Beginning with FreeM 0.1.7, routines invoked in this manner are no longer required to perform their own namespace setup with @code{VIEW} commands.
1.22 snw 310:
311: @section %SYSINIT Routine
312:
1.36 snw 313: The @code{%SYSINIT} routine runs every time a FreeM interpreter process starts. This routine defines some useful constants, enables handling of @code{TRIGGER} events, and handles the execution of code passed via the @code{-x|--execute} or routines passed via @code{-r|--routine}.
1.22 snw 314:
1.28 snw 315: Do not modify the supplied @code{%SYSINIT} routine to add site-specific startup items. Instead, create a @code{LCLINIT} routine in the @code{USER} namespace of one or more environments. @code{%SYSINIT} will automatically run @code{LCLINIT} each time it starts.
1.1 snw 316:
317: @section Command-Line Options
1.22 snw 318: @cindex options, command-line
1.1 snw 319:
320: @table @asis
321:
322: @item @option{-d}, @option{--daemon}
1.22 snw 323: Starts the FreeM environment daemon, exactly one of which must be running at all times in order for FreeM interpreter and fmadm processes to function.
1.1 snw 324:
325: @item @option{-e}, @option{--environment}
326: Selects the environment to be used. If no environment is specified, @code{DEFAULT} is used.
327:
328: @item @option{-k}, @option{--nofork}
1.22 snw 329: When used with @option{-d} or @option{--daemon}, causes the FreeM environment daemon to run instead in the foreground. Useful for debugging.
1.1 snw 330:
331: @item @option{-S}, @option{--shmsize}
332: When used with @option{-d} or @option{--daemon}, specifies the number of bytes of shared memory FreeM will allocate for the @code{LOCK} table, job table, and IPC table. This will determine the maximum number of concurrent FreeM processes and @code{LOCK}s available in this environment.
333:
334: @item @option{-c}, @option{--config}
335: Specify a configuration file other than @code{$PREFIX/etc/freem.conf}.
336:
337: @item @option{-h}, @option{--help}
338: Display a help message showing valid FreeM options.
339:
340: @item @option{-i}, @option{--import}
341: Causes your UNIX environment variables to be imported into FreeM's local symbol table.
342:
343: @item @option{-f}, @option{--filter}
344: Allows your M routines to be used as UNIX filters.
345:
346: @item @option{-n @emph{<namespace-name>}}, @option{--namespace=@emph{<namespace-name>}}
1.22 snw 347: Selects the FreeM namespace to be entered on startup. Must be defined in @file{/etc/<environment>/freem.conf}.
1.1 snw 348:
349: @item @option{-r @emph{<entryref>}}, @option{--routine=@emph{<entryref>}}
1.28 snw 350: Causes @code{<entryref>} to be executed at load, instead of @code{%SYSINIT}.
1.1 snw 351:
352: @item @option{--standard=@emph{<standard>}}
353: Sets the default FreeM dialect to use for new routine buffers.
354:
355: Valid values for @code{@emph{<standard>}} are as follows:
356:
357: @table @code
358: @item @code{M77}
359: Restricts FreeM to use only features specified by the 1977 M standard.
360: @item @code{M84}
361: Restricts FreeM to use only features specified by the 1984 M standard.
362: @item @code{M90}
363: Restricts FreeM to use only features specified by the 1990 M standard.
364: @item @code{M95}
365: Restricts FreeM to use only features specified by the 1995 M standard.
366: @item @code{MDS}
367: Restricts FreeM to use only features proposed by the Millennium Draft Standard.
368: @item @code{M5}
369: Restricts FreeM to use only features proposed by the upcoming M5 standard.
370: @item @code{FREEM}, @code{EXTENDED}
371: Removes all standards-based restrictions and allows full access to all FreeM features. This is the default value of @code{$DIALECT}.
372: @end table
373:
374: Please note that FreeM is not entirely standards-compliant, regardless of the value of @code{@emph{<standard>}}.
375:
376: @item @option{-v}, @option{--version}
377: Displays FreeM version information.
378:
379: @item @option{-x @emph{<mcode>}}, @option{--execute=@emph{<mcode>}}
1.22 snw 380: Executes M code @code{<mcode>} at startup.
1.1 snw 381:
382: @end table
383:
384: @section Using FreeM for Shell Scripting
385: @cindex routines, as shell scripts
386: @cindex shebang line
387: @cindex shell scripting
388:
389: FreeM M routines can be used as shell scripts by providing a @emph{shebang} line beginning with @code{#!/path/to/freem} as the first line of the routine.
390: The following example presumes that FreeM is installed at @file{/usr/local/bin/freem} and uses the @code{USER} namespace:
391:
392: @example
393: #!/usr/local/bin/freem
394: MYSCRIPT ;
395: SET ^$JOB($JOB,"NAMESPACE")="USER"
396: WRITE "This is output from an M routine used as a shell script.",!
397: Q
398: @end example
399:
400: Currently, the script needs to have a @file{.m} file extension. You will also need to select an appropriate namespace in your script using the @code{SET ^$JOB($JOB,"NAMESPACE")="@emph{<namespace>}"} command before attempting to call other routines or access globals.
401:
402: You will also need to set the script's permissions to @emph{executable} in order for this to work:
403:
404: @example
405: $ chmod +x @emph{myscript.m}
406: @end example
407:
1.22 snw 408: @node The FreeM Environment Daemon
409: @chapter The FreeM Environment Daemon
1.1 snw 410: @cindex daemon, freem
411:
1.22 snw 412: The FreeM environment daemon manages shared resources for a given FreeM environment. These include the lock table, job table, inter-process communication, and concurrency control for transaction processing. Unlike some M implementations, the FreeM environment daemon does @emph{not} function as a write daemon for global storage.
413:
414: One daemon process is required per FreeM environment, and can be started in the following ways, in order of preference:
1.1 snw 415:
1.22 snw 416: @example
417: $ sudo fmadm start environment [-e=<environment-name>]
418: @end example
1.1 snw 419:
420: @example
1.22 snw 421: $ freem --daemon [--nofork] [--environment=<environment-name>] [--shmsize=<bytes>]
1.1 snw 422: @end example
423:
424: If the daemon is started with @option{--nofork}, it will run in the foreground and its output will be reflected on the terminal. Otherwise, the daemon will run as a child process in the background and immediately return terminal control to the shell. The latter option is recommended in most cases.
425:
426: The @option{--environment} option will start the daemon for the specified @emph{environment-name}. The default environment, if unspecified, is called @code{DEFAULT}. If using an environment other than @code{DEFAULT}, interpreter processes that wish to also connect to the same environment must also use the @option{--environment} option when starting, and @code{libfreem} clients must also pass the environment name as the first argument to the @code{freem_init()} function. Environments allow you to run multiple, isolated instances of FreeM on the same machine, whose globals and routines are distinct and unique.
427:
428: The @option{--shmsize} option specifies the size in bytes of the FreeM shared memory segment. The default is 4194304 bytes. Increasing the size of the FreeM shared memory segment will, at the cost of increased memory usage, increase the number of concurrent jobs and lock table entries available to the environment; decreasing the size of the segment will have the expected opposite effect. Note that you must also pass @option{--shmsize} with the same number of bytes to any interpreter process to be used with an environment whose daemon uses a non-default shared memory segment size.
429:
430: Attempting to start a FreeM interpreter process without a daemon running with the same environment name will result in an error.
431:
432: @node The FreeM Direct-Mode Environment
433: @chapter The FreeM Direct-Mode Environment
434: @cindex command line interface
435: @cindex direct mode
436: @cindex execution, interactive
437: @cindex modes, programmer
438:
439:
440: The FreeM direct-mode environment is the mode entered when FreeM is invoked without the use of @option{-r @emph{<entryref>}} or @option{--routine=@emph{<entryref>}}:
441:
442: @example
1.54 ! snw 443: Coherent Logic Development FreeM version 0.64.0 (x86_64-pc-linux-gnu)
1.1 snw 444: Copyright (C) 2014, 2020, 2021 Coherent Logic Development LLC
445:
446:
447: USER>
448: @end example
449:
1.25 snw 450: The prompt (@code{DEFAULT.USER>}) displays the current environment and namespace, @code{DEFAULT} and @code{USER}, respsectively. If any uncommitted direct-mode transactions have been started, the prompt will change to reflect the current value of @code{@ref{$TLEVEL}}:
1.1 snw 451:
452: @example
1.22 snw 453: TL1:DEFAULT.USER>
1.1 snw 454: @end example
455:
456: In the above example, @code{TL1} indicates that @code{@ref{$TLEVEL}} is currently @emph{1}.
457:
458: @section Direct-Mode Commands
459:
460: When you are in direct mode, in addition to M commands, a number of internal commands are available to help developers be more productive:
461:
462: @table @asis
463:
464: @item @command{?}
465: Accesses FreeM online help. Requires GNU @command{info(1)} to be installed on your local system.
466:
467: @item @command{events}
468: Writes a list of @emph{event classes} and their @code{ABLOCK} counts:
469:
470: @example
1.22 snw 471: DEFAULT.USER> events
1.1 snw 472:
473: Event Class Processing Mode ABLOCK Count
474: ----------- --------------- ------------
475: COMM Disabled 0
476: HALT Disabled 0
477: IPC Disabled 0
478: INTERRUPT Disabled 0
479: POWER Disabled 0
480: TIMER Disabled 0
481: USER Disabled 0
482: WAPI Disabled 0
483: TRIGGER Disabled 0
484: @end example
485:
486:
487: @anchor{trantab}
488: @item @command{trantab}
489: Displays information about any uncommitted transactions currently in-flight for this process.
490:
1.22 snw 491: @anchor{glstat}
492: @item @command{trantab}
493: Displays statistics about globals that have been opened in the current FreeM process.
494:
1.1 snw 495: @anchor{jobtab}
496: @item @command{jobtab}
497: Displays a summary of the FreeM job table.
498:
499: @anchor{locktab}
500: @item @command{locktab}
501: Displays a list of @code{LOCK}s held in the current environment.
502:
503: @anchor{rbuf}
504: @item @command{rbuf}
505: Lists the status of all FreeM routine buffers.
506:
507: @anchor{wh}
508: @item @command{wh}
509: Forces an immediate flush of this process's @code{readline} history buffer to disk.
510:
511: @anchor{shmstat}
512: @item @command{shmstat}
513: Displays the configuration of FreeM shared memory. Intended only for advanced debugging of the FreeM environment.
514:
515: @anchor{shmpages}
516: @item @command{shmpages}
517: Lists the status of each FreeM shared memory page. Intended only for advanced debugging of the FreeM environment.
518:
519: @anchor{history}
520: @item @command{history}
521: Prints a list of all the direct-mode commands you have entered across all sessions.
522:
523: @anchor{rcl}
524: @item @command{rcl @emph{<history-index>}}
525: Allows you to recall command number @emph{<history-index>} and run it again. Obtain the value for @emph{<history-index>} from the output of the @command{history} command.
526:
527: @item @command{!!}
528: Launches a subshell within the FreeM direct mode, allowing the user to run operating system commands.
529:
530: @example
1.22 snw 531: DEFAULT.USER> !!
1.1 snw 532:
533: Type Ctrl-D to exit from the shell
534: $ uname -a
535: Linux hesperos 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux
536: $ exit
537:
1.22 snw 538: DEFAULT.USER>
1.1 snw 539: @end example
540:
541: @item @command{!@emph{<external-command>}}
1.28 snw 542: Invokes a shell to run @emph{<external-command>} from within FreeM. This temporarily disables @command{SIGALRM} handling in FreeM, which may interrupt the use of event-driven M programming commands including @command{ASTART} and @command{ASTOP}.
1.1 snw 543:
544: If the @command{>} character is supplied immediately preceding @emph{<external-command>}, FreeM will append the contents of an M local or global variable referenced in @code{^$JOB($JOB,"PIPE_GLVN")} to the standard input stream of @emph{<external-command>}.
545:
546: If the @command{<} character is supplied immediately preceding @emph{<external-command>}, FreeM will take the standard output stream of @emph{<external-command>} and store it in M local or global variable referenced by @code{^$JOB($JOB,"PIPE_GLVN")}.
547:
548: The data value in the unsubscripted M local or global contains the number of lines in the input or output. Subscripts @code{(1)..(@emph{n})} contain the data for lines 1-@emph{n}.
549:
550: @end table
551:
552: @cindex HALT, in direct-mode
553: If you issue a @code{@ref{HALT}} command at the direct-mode prompt, you will exit out of FreeM. However, if you issue a @code{@ref{HALT}} command when @code{@ref{$TLEVEL}} is greater than zero, you will be given the opportunity to commit or rollback any pending transactions:
554:
555: @example
1.22 snw 556: DEFAULT.USER> TSTART
1.1 snw 557:
558:
1.22 snw 559: TL1:DEFAULT.USER> SET ^MYGLOBAL=1
1.1 snw 560:
561:
1.22 snw 562: TL1:DEFAULT.USER> HALT
1.1 snw 563:
564: UNCOMMITTED TRANSACTIONS EXIST:
565:
566: $TLEVEL 1*
567: Operations for Transaction ID: k8xj1de
568: 1: action = 0 key = ^MYGLOBAL data = 1
569:
570: Would you like to c)ommit or r)ollback the above transactions and their operations? ($TLEVEL = 1) r
571:
572:
573: Transactions have been rolled back.
574: @end example
575:
576: In the above example, the user selected @code{r} to rollback the single pending transaction.
577:
578: @section REPL Functionality
579: @cindex REPL, direct-mode
580:
581: FreeM direct mode allows you to enter M expressions directly from the direct-mode prompt, as long as they begin with a number:
582:
583: @example
1.22 snw 584: DEFAULT.USER> S DENOM=10
1.1 snw 585:
586:
1.22 snw 587: DEFAULT.USER> 100/DENOM
1.1 snw 588:
589: 10
1.22 snw 590: DEFAULT.USER>
1.1 snw 591: @end example
592:
593: Such expressions will be immediately evaluated, and the result printed on @code{@ref{$IO}}.
594:
1.36 snw 595: @node Debugging
596: @chapter Debugging
597: @cindex debugging
598:
599: @section Debugging Synopsis
600: FreeM includes an interactive debugger, entered using the @code{BREAK "DEBUG"} command. The debugger is also entered if @code{Ctrl-C} is pressed, @code{Ctrl-C} handling is enabled, and you are in direct mode.
601:
602: If you would like to enter the debugger automatically each time an error is encountered, add the following to your @code{LCLINIT} routine:
603:
604: @example
605: S $ETR="B ""DEBUG"""
606: @end example
607:
608: @section Debugging Commands
609: The debugger uses its own unique command language, where M commands are unavailable. Commands are as follows:
610:
611: @table @asis
612: @item @code{exit}, @code{quit}
613: Exits the debugger and returns to direct mode or normal program execution.
614: @item @code{e} @emph{glvn}, @code{examine} @emph{glvn}
615: Prints the value of @emph{glvn} to the terminal.
616: @item @code{t}, @code{trace}
617: Toggles @emph{trace mode} on and off. When trace mode is on, FreeM will display information about each @code{DO} or @code{GOTO} command encountered, including the routine which invoked the branch, which type of branch was invoked, and the target of the branch.
618: @item @code{s}, @code{step}
619: Single-steps through FreeM code command-by-command.
620: @item @code{n}, @code{next}
621: Single-steps through FreeM code line-by-line.
622: @item @code{c}, @code{cont}, @code{continue}
623: Resumes normal program execution, disabling single-step mode.
624: @item @code{bt}, @code{backtrace}
625: Produces a stack trace.
626: @item @code{h}, @code{halt}
627: Halts the process being debugged and returns control to the operating system.
628: @item @code{w [[+|-|?]@emph{<glvn>}]}, @code{watch [[+|-|?]@emph{<glvn>}]}
629: With no arguments, toggles watchpoints on and off. With @code{+}, adds @emph{<glvn>} to the watchlist. With @code{-}, removes @emph{<glvn>} from the watchlist. With @code{?}, queries the watch status of @emph{<glvn>}.
630: @end table
631:
1.1 snw 632: @node Directives
633: @chapter Directives
634: @cindex directives
635:
636: In FreeM, a directive is an instruction embedded in an M comment, and passed to the interpreter to affect a change that is specific to the current routine only.
637:
638: The format of a directive is @code{;%@emph{<directive-name>}}, where @code{@emph{<directive-name>}} is one of the directives listed below.
639:
640: @menu
641: * %DIALECT:: Sets the M dialect in effect.
642: @end menu
643:
644: @anchor{%DIALECT}
645: @section %DIALECT
646: @cindex %DIALECT
647: @cindex directives, %DIALECT
648:
649: Sets the M dialect in effect for the current routine buffer; also sets the @code{$DIALECT} special variable to match. See also @ref{$DIALECT}.
650:
651: @emph{Syntax}
652:
653: @example
654: ;%DIALECT @emph{<dialect>}
655: @end example
656:
657: Valid values for @code{@emph{<dialect>}} are as follows:
658:
659: @table @code
660: @item @code{M77}
661: Restricts FreeM to use only features specified by the 1977 M standard.
662: @item @code{M84}
663: Restricts FreeM to use only features specified by the 1984 M standard.
664: @item @code{M90}
665: Restricts FreeM to use only features specified by the 1990 M standard.
666: @item @code{M95}
667: Restricts FreeM to use only features specified by the 1995 M standard.
668: @item @code{MDS}
669: Restricts FreeM to use only features proposed by the Millennium Draft Standard.
670: @item @code{M5}
671: Restricts FreeM to use only features proposed by the upcoming M5 standard.
672: @item @code{FREEM}, @code{EXTENDED}
673: Removes all standards-based restrictions and allows full access to all FreeM features. This is the default value of @code{%DIALECT}.
674: @end table
675:
676: Please note that FreeM is not entirely standards-compliant, regardless of the value of @code{%DIALECT}.
677:
678:
679: @node Intrinsic Special Variables
680: @chapter Intrinsic Special Variables
681: @cindex variables, intrinsic special
682:
683: @menu
684: * $DEVICE:: $IO device status.
685: * $DIALECT:: Current M dialect.
686: * $ECODE:: Latest M error code.
687: * $ESTACK:: Error stack info.
688: * $ETRAP:: Standard error handler code.
689: * $HOROLOG:: Current date and time.
690: * $IO:: Current I/O device.
691: * $JOB:: PID of current process.
692: * $KEY:: Characters terminating last @code{READ} command.
693: * $PDISPLAY:: Current primary MWAPI display.
694: * $PRINCIPAL:: I/O channel of terminal.
695: * $REFERENCE:: Most recent global reference.
696: * $QUIT:: Whether a @code{QUIT} command requires an argument in the current execution context.
697: * $STACK:: Current program execution stack level.
698: * $STORAGE:: Number of bytes available in the heap.
699: * $SYSTEM:: MDC system ID of FreeM.
700: * $TEST:: Truth value of last conditional expression or result of certain @code{LOCK} operations.
701: * $TLEVEL:: Current level of transaction nesting.
1.42 snw 702: * $WITH:: Current variable prefix set by @code{ZWITH} command.
1.1 snw 703: * $X:: Current horizontal screen position.
704: * $Y:: Current vertical screen position.
705: * $ZA:: Current position of file on @code{$IO}.
706: * $ZB:: Most recent keystroke.
707: * $ZCONTROLC:: Control-C handling flag.
708: * $ZDATE:: Current date in locale-specific representation.
709: * $ZERROR:: Last error message.
710: * $ZHOROLOG:: Date and time, including milliseconds.
711: * $ZINRPT:: State of the interrupt enable/disable flag.
712: * $ZJOB:: PID of parent process, if applicable.
713: * $ZLOCAL:: Last local variable reference.
714: * $ZNAME:: Name of current M routine.
715: * $ZPRECISION:: Digits of arithmetical precision.
716: * $ZREFERENCE:: Last gvn referenced.
717: * $ZSYSTEM:: Return value of last external command.
718: * $ZTIME:: Current time in locale-specific representation.
719: * $ZTRAP:: Entryref to be executed on error condition.
720: * $ZUT:: Microseconds since the UNIX epoch.
721: * $ZVERSION:: Version of FreeM and GNU host triplet.
722: @end menu
723:
724: @node $DEVICE
725: @section $DEVICE
726: @cindex $DEVICE
727: @cindex intrinsic special variables, $DEVICE
728:
729: Returns the status of the device currently in use.
730:
731: If @code{$DEVICE} returns @emph{1}, an error condition exists on the current device. In this case, there will be two additional fields separated by commas, indicating the internal FreeM error code representing the error present on the device and a text explanation of the error.
732:
733: @node $DIALECT
734: @section $DIALECT
735: @cindex $DIALECT
736: @cindex intrinsic special variables, $DIALECT
737:
738: Returns or sets the language dialect of the current routine.
739:
740: Valid values for @code{$DIALECT} are as follows:
741:
742: @table @code
743: @item @code{M77}
744: Restricts FreeM to use only features specified by the 1977 M standard.
745: @item @code{M84}
746: Restricts FreeM to use only features specified by the 1984 M standard.
747: @item @code{M90}
748: Restricts FreeM to use only features specified by the 1990 M standard.
749: @item @code{M95}
750: Restricts FreeM to use only features specified by the 1995 M standard.
751: @item @code{MDS}
752: Restricts FreeM to use only features proposed by the Millennium Draft Standard.
753: @item @code{M5}
754: Restricts FreeM to use only features proposed by the upcoming M5 standard.
755: @item @code{FREEM}, @code{EXTENDED}
756: Removes all standards-based restrictions and allows full access to all FreeM features. This is the default value of @code{$DIALECT}.
757: @end table
758:
759: Please note that FreeM is not entirely standards-compliant, regardless of the value of @code{$DIALECT}.
760:
761: @node $ECODE
762: @section $ECODE
763: @cindex $ECODE
764: @cindex intrinsic special variables, $ECODE
765:
766: Returns a comma-delimited list of error conditions currently present, and is writable. An empty @code{$ECODE} indicates no errors.
767:
1.28 snw 768: Writing a value in the format @code{,<error-code>,} into @code{$ECODE} will raise that error condition.
769:
1.1 snw 770: @node $ESTACK
771: @section $ESTACK
772: @cindex $ESTACK
773: @cindex intrinsic special variables, $ESTACK
774:
775: Returns the depth of the program execution stack since the last time @code{$ESTACK} was @code{NEW}ed. @code{NEW}-able, but not @code{SET}-able. Differs from the @code{@ref{$STACK}} ISV in that it is @code{@ref{NEW}}-able, and resets to a value of 0 when @code{@ref{NEW}}ed.
776:
777: @node $ETRAP
778: @section $ETRAP
779: @cindex $ETRAP
780: @cindex intrinsic special variables, $ETRAP
781:
782: Sets or retrieves the M code that is run when an error is encountered or @code{@ref{$ECODE}} is set to a non-blank value. @code{$ETRAP} code executes when @code{$ECODE} becomes non-blank.
783:
784:
785: @node $HOROLOG
786: @section $HOROLOG
787: @cindex $HOROLOG
788: @cindex intrinsic special variables, $HOROLOG
789:
790: Returns a string containing the current date and time as @code{<days>,<seconds>}, where @code{<days>} represents the number of days since the M epoch (midnight on 31 December 1840),
791: and @code{<seconds>} represents the number of seconds since the most recent midnight.
792:
793: @cartouche
794: @quotation
795: @emph{FreeM Extension}
796:
797: In FreeM, @code{$HOROLOG} is @code{@ref{SET}}table. Setting @code{$HOROLOG} will set the system clock if your user account has the appropriate permissions. If your user account does not have permissions to modify the system clock, FreeM will raise a @code{ZPROTECT} error.
798: @end quotation
799: @end cartouche
800:
801: @node $IO
802: @section $IO
803: @cindex $IO
804: @cindex intrinsic special variables, $IO
805:
806: Represents the current input/output device. Read-only.
807:
808: @node $JOB
809: @section $JOB
810: @cindex $JOB
811: @cindex intrinsic special variables, $JOB
812:
813: Represents the process ID of the FreeM instance currently in use.
814:
815: @node $KEY
816: @section $KEY
817: @cindex $KEY
818: @cindex intrinsic special variables, $KEY
819:
820: Represents the sequence of control characters that terminated the last @code{@ref{READ}} command on @code{@ref{$IO}}.
821:
822: @node $PDISPLAY
823: @section $PDISPLAY
824: @cindex $PDISPLAY
825: @cindex intrinsic special variables, $PDISPLAY
826:
827: Represents the current principal display for M Windowing API operations. Commonly used as an index into the @code{@ref{^$DISPLAY}} structured system variable.
828:
829: @node $PRINCIPAL
830: @section $PRINCIPAL
831: @cindex $PRINCIPAL
832: @cindex intrinsic special variables, $PRINCIPAL
833:
834: Represents the primary input/output device. Usually a terminal or virtual terminal.
835:
836: @node $REFERENCE
837: @section $REFERENCE
838: @cindex $REFERENCE
839: @cindex intrinsic special variables, $REFERENCE
840:
841: Returns the last @emph{glvn} referenced. Can be @code{@ref{SET}}, and also stacked with @code{@ref{NEW}}.
842:
843: @node $QUIT
844: @section $QUIT
845: @cindex $QUIT
846: @cindex intrinsic special variables, $QUIT
847:
848: If the current execution context was invoked as an extrinsic function, @code{$QUIT} returns @emph{1}. Otherwise, returns @emph{0}.
849:
850: When @code{$QUIT} returns @emph{1}, a subsequent @code{@ref{QUIT}} command must have an argument.
851:
852: @node $STACK
853: @section $STACK
854: @cindex $STACK
855: @cindex intrinsic special variables, $STACK
856:
857: Represents the current stack level.
858:
859: @node $STORAGE
860: @section $STORAGE
861: @cindex $STORAGE
862: @cindex intrinsic special variables, $STORAGE
863:
864: Represents the number of bytes of free space available in FreeM's heap.
865:
866: @node $SYSTEM
867: @section $SYSTEM
868: @cindex $SYSTEM
869: @cindex intrinsic special variables, $SYSTEM
870:
871: Returns the MDC system ID of FreeM, as well as the environment ID of the current environment.
872:
873: @node $TEST
874: @section $TEST
875: @cindex $TEST
876: @cindex intrinsic special variables, $TEST
877:
878: @code{$TEST} is a writable, @code{@ref{NEW}}-able ISV that is @emph{1} if the most recently evaluated expression was @emph{true}. Otherwise, returns @emph{0}.
879:
880: @code{$TEST} is implicitly @code{NEW}ed when entering a new stack frame for extrinsic functions and argumentless @code{@ref{DO}}. @code{$TEST}
881: is @emph{not} implicitly @code{NEW}ed when a new stack frame is entered with an argumented @code{DO}.
882:
883: For single-line @code{@ref{IF}} or @code{@ref{ELSE}} expressions, you may use @code{@ref{THEN}} to stack @code{$TEST} until the end of the line. All new code should employ @code{THEN} in this manner, as stacking @code{$TEST} prevents a wide range of coding errors that can be very challenging to detect and eliminate.
884:
885: @node $TLEVEL
886: @section $TLEVEL
887: @cindex $TLEVEL
888: @cindex intrinsic special variables, $TLEVEL
889:
890: Returns a numeric value indicating the current level of transaction nesting in the process. When @code{$TLEVEL} is greater than @emph{0},
891: uncommitted transactions exist.
892:
893: @node $WITH
894: @section $WITH
895: @cindex $WITH
896: @cindex intrinsic special variables, $WITH
897:
1.42 snw 898: Returns the variable prefix set by the @code{@ref{ZWITH}} command.
1.1 snw 899:
900: @node $X
901: @section $X
902: @cindex $X
903: @cindex intrinsic special variables, $X
904:
905: Represents the current column position of the FreeM cursor.
906:
907: @cartouche
908: @quotation
909: In FreeM, setting @code{$X} will move the FreeM cursor.
910: @end quotation
911: @end cartouche
912:
913:
914: @node $Y
915: @section $Y
916: @cindex $Y
917: @cindex intrinsic special variables, $Y
918:
919: Represents the current row position of the FreeM cursor.
920:
921: @cartouche
922: @quotation
923: In FreeM, setting @code{$Y} will move the FreeM cursor.
924: @end quotation
925: @end cartouche
926:
927:
928: @node $ZA
929: @section $ZA
930: @cindex $ZA
931: @cindex intrinsic special variables, $ZA
932: @cindex intrinsic special variables, implementation-specific
933:
934: On the @code{HOME} device, always @code{0}. On other devices, returns the current position of the file opened on I/O channel @code{@ref{$IO}}.
935:
936: @node $ZB
937: @section $ZB
938: @cindex $ZB
939: @cindex intrinsic special variables, $ZB
940: @cindex intrinsic special variables, implementation-specific
941:
942: Represents the last keystroke.
943:
944: @node $ZCONTROLC
945: @section $ZCONTROLC
946: @cindex $ZCONTROLC
947: @cindex intrinsic special variables, $ZCONTROLC
948: @cindex intrinsic special variables, implementation-specific
949:
950: Returns the status of the Ctrl-C flag and resets it to @emph{false}.
951:
952: @node $ZDATE
953: @section $ZDATE
954: @cindex $ZDATE
955: @cindex intrinsic special variables, $ZDATE
956: @cindex intrinsic special variables, implementation-specific
957:
958: Returns the current date, in the preferred representation for the current system locale.
959:
960: @node $ZERROR
961: @section $ZERROR
962: @cindex $ZERROR
963: @cindex intrinsic special variables, $ZERROR
964: @cindex intrinsic special variables, implementation-specific
965:
966: Returns the last error message.
967:
968: @node $ZHOROLOG
969: @section $ZHOROLOG
970: @cindex $ZHOROLOG
971: @cindex intrinsic special variables, $ZHOROLOG
972: @cindex intrinsic special variables, implementation-specific
973:
974: Output @code{@ref{$HOROLOG}}-style time, with the addition of milliseconds.
975:
976: @node $ZINRPT
977: @section $ZINRPT
978: @cindex $ZINRPT
979: @cindex intrinsic special variables, $ZINRPT
980: @cindex intrinsic special variables, implementation-specific
981:
982: Gets or sets the interrupt enable/disable flag.
983:
984: @node $ZJOB
985: @section $ZJOB
986: @cindex $ZJOB
987: @cindex intrinsic special variables, $ZJOB
988: @cindex intrinsic special variables, implementation-specific
989:
990: Returns the @code{@ref{$JOB}} value of the parent process if the current process was started by a @code{@ref{JOB}} command. Otherwise, returns an empty string.
991:
992: @node $ZLOCAL
993: @section $ZLOCAL
994: @cindex $ZLOCAL
995: @cindex intrinsic special variables, $ZLOCAL
996: @cindex intrinsic special variables, implementation-specific
997:
998: Returns the last local variable referenced.
999:
1000: @node $ZNAME
1001: @section $ZNAME
1002: @cindex $ZNAME
1003: @cindex intrinsic special variables, $ZNAME
1004: @cindex intrinsic special variables, implementation-specific
1005:
1006: Returns the name of the current routine.
1007:
1008: @node $ZPRECISION
1009: @section $ZPRECISION
1010: @cindex $ZPRECISION
1011: @cindex intrinsic special variables, $ZPRECISION
1012: @cindex intrinsic special variables, implementation-specific
1013:
1014: Gets or sets the number of digits of numeric precision used for fixed-point decimal arithmetic. If @code{^$JOB($JOB,"MATH")} is @code{IEEE754}, @code{$ZPRECISION} defaults to 16 digits, with a maximum of 16 digits. If @code{^$JOB($JOB,"MATH")} is @code{FIXED}, @code{$ZPRECISION} defaults to 100 digits, with a maximum of 20,000 digits.
1015:
1016: @xref{^$JOB}.
1017:
1018: @node $ZREFERENCE
1019: @section $ZREFERENCE
1020: @cindex $ZREFERENCE
1021: @cindex intrinsic special variables, $ZREFERENCE
1022: @cindex intrinsic special variables, implementation-specific
1023:
1024: Returns the last @emph{gvn} referenced.
1025:
1026: @node $ZSYSTEM
1027: @section $ZSYSTEM
1028: @cindex $ZSYSTEM
1029: @cindex intrinsic special variables, $ZSYSTEM
1030: @cindex intrinsic special variables, implementation-specific
1031:
1032: Represents the return value of the last external command run with @code{!}.
1033:
1034: @node $ZTIME
1035: @section $ZTIME
1036: @cindex $ZTIME
1037: @cindex intrinsic special variables, $ZTIME
1038: @cindex intrinsic special variables, implementation-specific
1039:
1040: Returns the system time in the preferred representation for the current system locale.
1041:
1042: @node $ZTRAP
1043: @section $ZTRAP
1044: @cindex $ZTRAP
1045: @cindex intrinsic special variables, $ZTRAP
1046: @cindex intrinsic special variables, implementation-specific
1047:
1048: Sets or retrieves the entryref to be executed when an M program execution error occurs under FreeM-style or DSM 2.0-style error processing.
1049:
1050: In FreeM-style error processing, @code{$ZTRAP} is specific to each program execution stack level.
1051:
1052: In DSM 2.0-style error processing, @code{$ZTRAP} is the same for all program execution stack levels.
1053:
1054: When FreeM encounters an error, if @code{$ZTRAP} is nonempty and @code{$ETRAP} is empty, FreeM will perform an implicit @code{@ref{GOTO}} to the entryref indicated in @code{$ZTRAP}.
1055:
1056: If @code{$ETRAP} is nonempty when FreeM encounters an error, the value of @code{$ZTRAP} is ignored, whether FreeM-style or DSM 2.0-style error processing is enabled.
1057:
1058: @node $ZUT
1059: @section $ZUT
1060: @cindex $ZUT
1061: @cindex intrinsic special variables, $ZUT
1062: @cindex intrinsic special variables, implementation-specific
1063:
1064: Returns the number of microseconds elapsed since the UNIX epoch (Jan 1, 1970 0:00:00).
1065:
1066: @node $ZVERSION
1067: @section $ZVERSION
1068: @cindex $ZVERSION
1069: @cindex intrinsic special variables, $ZVERSION
1070: @cindex intrinsic special variables, implementation-specific
1071:
1072: Returns the version of FreeM in use, as well as the GNU host triplet for the current FreeM build.
1073:
1074: See @emph{https://wiki.osdev.org/Target_Triplet}.
1075:
1076: @node Intrinsic Functions
1077: @chapter Intrinsic Functions
1078:
1079: @menu
1080: * $ASCII():: Return ASCII code for character in string.
1081: * $CHAR():: Return character for one or more ASCII codes.
1082: * $DATA():: Retrieve definition and characteristics of array node.
1083: * $EXTRACT():: Return a substring of a string.
1084: * $FIND():: Find position of substring within string.
1085: * $FNUMBER():: Format a number according to formatting codes.
1086: * $GET():: Return value of glvn or a default if undefined.
1087: * $INSTANCEOF():: Determine if lvn is an instance of a class.
1088: * $JUSTIFY():: Right-justify a string based on specified length.
1089: * $LENGTH():: Return length or delimiter-based piece count of string.
1090: * $NAME():: Return canonical name from string representation of glvn.
1091: * $NEXT():: Return next numeric subscript following given glvn.
1092: * $ORDER():: Return next subscript at same level of specified glvn.
1093: * $PIECE():: Return one or more delimited pieces of a string.
1094: * $QLENGTH():: Return subscript count of glvn.
1095: * $QSUBSCRIPT():: Return a specified subscript from glvn.
1096: * $QUERY():: Return next subscript of specified glvn.
1097: * $RANDOM():: Return pseudorandom integer up to a maximum value.
1098: * $REVERSE():: Reverse a string.
1099: * $SELECT():: Return value from first true condition in list of expressions.
1100: * $STACK():: Return information about the program stack.
1101: * $TEXT():: Return line of code from a routine.
1102: * $TRANSLATE():: Substitute specified characters in a string.
1103: * $TYPE():: Return class of the specified lvn.
1104: * $VIEW():: Retrieve implementation-specific information.
1105: * $ZBOOLEAN():: Perform boolean operations on numeric arguments.
1106: * $ZCALL():: Unknown.
1107: * $ZCRC():: Generate checksum of a string argument.
1108: * $ZDATA():: Unknown.
1109: * $ZDATE():: Convert @code{@ref{$HOROLOG}} string into human-readable date.
1110: * $ZEDIT():: Unknown.
1111: * $ZHOROLOG():: Convert date/time values to @code{@ref{$HOROLOG}} format.
1112: * $ZKEY():: Unknown.
1113: * $ZLENGTH():: Unknown.
1114: * $ZLSD():: Compute Levenshtein distance between two arguments.
1115: * $ZM():: Unknown.
1116: * $ZNAME():: Unknown.
1.52 snw 1117: * $ZNEXT():: Return glvn of next numeric subscript following given glvn.
1.1 snw 1118: * $ZORDER():: Unknown.
1119: * $ZPIECE():: Unknown.
1120: * $ZPREVIOUS():: Unknown.
1121: * $ZREPLACE():: Replace all instances of a substring within a string.
1122: * $ZSYNTAX():: Perform syntax check on string argument.
1123: * $ZTIME():: Convert a @code{@ref{$HOROLOG}} string into human-readable time.
1124: @end menu
1125:
1126: @node $ASCII()
1127: @section $ASCII
1128: @cindex $ASCII
1129: @cindex intrinsic functions, $ASCII
1130:
1131: Returns the ASCII code (in decimal) for one character in a string.
1132:
1133: @example
1134: SET RESULT=$ASCII(@emph{<string>}[,@emph{<index>}])
1135: @end example
1136:
1137:
1138: If @emph{<index>} is not supplied, @code{$ASCII} will return the ASCII code of the first character. Otherwise, returns the ASCII code of the character at position @emph{<index>}.
1139:
1140: @node $CHAR()
1141: @section $CHAR
1142: @cindex $CHAR
1143: @cindex intrinsic functions, $CHAR
1144:
1145: Returns a string of characters corresponding to a list of ASCII codes.
1146:
1147: @example
1148: SET RESULT=$CHAR(@emph{<ascii-code>}[,@emph{<ascii-code>},...])
1149: @end example
1150:
1151: @node $DATA()
1152: @section $DATA
1153: @cindex $DATA
1154: @cindex intrinsic functions, $DATA
1155:
1156: Returns a numeric value 0, 1, 10, or 11, depending on whether a referenced node is defined, has data, or has children:
1157:
1158: @example
1159: SET RESULT=$DATA(@emph{<node>})
1160: @end example
1161:
1162: The return values are as follows:
1163:
1164: @example
1165: 0: @emph{<node>} is undefined
1166: 1: @emph{<node>} has data but no children
1167: 10: @emph{<node>} has children but no data
1168: 11: @emph{<node>} has children and data
1169: @end example
1170:
1171: @node $EXTRACT()
1172: @section $EXTRACT
1173: @cindex $EXTRACT
1174: @cindex intrinsic functions, $EXTRACT
1175:
1176: Extracts a substring of a string.
1177:
1178: The first argument is the source string.
1179:
1180: The optional second argument specifies the starting position of the substring to extract, and defaults to @code{1}.
1181:
1182: The optional third argument specifies the ending position of the substring to extract, and defaults to the value of the second argument, or @code{1}.
1183:
1184: This example will extract the string @emph{FreeM} into the local variable @code{M}.
1185:
1186: @example
1187: SET NAME="FreeM is the best!"
1188: SET M=$EXTRACT(NAME,1,5)
1189: @end example
1190:
1191: It is also possible to use @code{$EXTRACT} on the left-hand side of a @code{SET} assignment in order to modify a substring:
1192:
1193: @example
1.22 snw 1194: DEFAULT.USER> SET FOO="ABCDEFG"
1.1 snw 1195:
1196:
1.22 snw 1197: DEFAULT.USER> SET $EXTRACT(FOO,1,3)="XYZ"
1.1 snw 1198:
1199:
1.22 snw 1200: DEFAULT.USER> WRITE FOO
1.1 snw 1201:
1202: XYZDEFG
1203: @end example
1204:
1205: @node $FIND()
1206: @section $FIND
1207: @cindex $FIND
1208: @cindex intrinsic functions, $FIND
1209:
1210: Finds the character immediately following the first occurence of a substring within a string.
1211:
1212: The first argument is the source string.
1213:
1214: The second argument is the substring to be located.
1215:
1216: The optional third argument indicates the position within the source string at which to begin searching.
1217:
1218: @node $FNUMBER()
1219: @section $FNUMBER
1220: @cindex $FNUMBER
1221: @cindex intrinsic functions, $FNUMBER
1222:
1223: Formats a number according to a particular set of formatting codes.
1224:
1225: The first argument is the number to format.
1226:
1.22 snw 1227: The second argument is the series of formatting codes:
1228:
1229: @table @asis
1230: @item 'P' or 'p'
1231: Will display negative numbers within parentheses instead of showing a minus sign.
1232: @item , (comma)
1233: Will add commas as thousands separators.
1234: @item +
1235: Will include a plus sign for positive numbers. Not compatible with 'P' or 'p'.
1236: @item -
1237: Will remove the minus sign from negative numbers. Not compatible with 'p' or 'P'.
1238: @item 't' or 'T'
1239: Will place the sign after the number instead of before the number.
1.23 snw 1240: @end table
1.22 snw 1241:
1242: The optional third argument is a number indicating how many digits to which the fractional part of the number will be zero-padded.
1.1 snw 1243:
1244: @node $GET()
1245: @section $GET
1246: @cindex $GET
1247: @cindex intrinsic functions, $GET
1248:
1249: Returns the value of a local, global, or SSVN if the specified item is defined, or a default value otherwise.
1250:
1251: The first argument is the local, global, or SSVN to be examined.
1252:
1253: The optional second argument is the default value to be returned if the referenced item is undefined, and defaults to the empty string.
1254:
1255: @node $INSTANCEOF()
1256: @section $INSTANCEOF
1257: @cindex $INSTANCEOF
1258: @cindex intrinsic functions, $INSTANCEOF
1259: @cindex object functions, $INSTANCEOF
1260:
1261: Returns @code{1} if the specified @emph{lvn} is an instance of class @emph{class}, or @code{0} otherwise.
1262:
1263: The first argument is a string representing a valid FreeM local variable.
1264:
1265: The second argument is a string representing a valid FreeM class.
1266:
1267: @example
1.22 snw 1268: DEFAULT.USER> N STR=$$^%STRING
1.1 snw 1269:
1.22 snw 1270: DEFAULT.USER> W $INSTANCEOF("STR","^%STRING")
1.1 snw 1271: 1
1272: @end example
1273:
1274: @node $JUSTIFY()
1275: @section $JUSTIFY
1276: @cindex $JUSTIFY
1277: @cindex intrinsic functions, $JUSTIFY
1278:
1279: Right-justifies a string based on a specified fixed length.
1280:
1281: The first argument is the source string.
1282:
1283: The second argument is the character length of the output.
1284:
1285: The optional third argument controls the number of fractional digits to be included in the output, and defaults to the number of digits specified in the first argument.
1286:
1287: @node $LENGTH()
1288: @section $LENGTH
1289: @cindex $LENGTH
1290: @cindex intrinsic functions, $LENGTH
1291:
1292: Returns the length of a string, or the number of items in a list delimited by a specified character (as used by @code{@ref{$PIECE()}}).
1293:
1294: The first argument is the source string.
1295:
1296: The optional second argument is the list delimiter to be used. When this argument is omitted, the length of the string in characters is returned.
1297:
1298: @node $NAME()
1299: @section $NAME
1300: @cindex $NAME
1301: @cindex intrinsic functions, $NAME
1302:
1303: Returns the canonical name reference along with some or all of its subscripts.
1304:
1305: The first argument is the source name.
1306:
1307: The optional second argument indicates the maximum subscript count to be returned, and defaults to the subscript count of the source name.
1308:
1309: @node $NEXT()
1310: @section $NEXT
1311: @cindex $NEXT
1312: @cindex intrinsic functions, $NEXT
1313:
1.25 snw 1314: Deprecated. Use @code{$ORDER} instead.
1.52 snw 1315: Returns the next numeric subscript of the specified glvn.
1316:
1317: @emph{Syntax}
1318:
1319: @example
1320: $NEXT(@emph{glvn})
1321: @end example
1322:
1323: @emph{Example}
1324:
1325: Assume the following array:
1326:
1327: @example
1328: ^foo(1)=""
1329: ^foo(2)=""
1330: @end example
1331:
1332: And the following code:
1333:
1334: @example
1335: W $ZNEXT(^foo(1)) ; => 2
1336: @end example
1.25 snw 1337:
1.1 snw 1338: @node $ORDER()
1339: @section $ORDER
1340: @cindex $ORDER
1341: @cindex intrinsic functions, $ORDER
1342:
1.25 snw 1343: Returns the previous subscript or next subscript in a local, global, or a subset of structured system variables.
1344:
1345: The first argument is the subscripted local, global, or SSVN.
1346:
1347: The optional second argument can be @code{1} to retrieve the next subscript, or @code{-1} to return the previous.
1348:
1.1 snw 1349: @node $PIECE()
1350: @section $PIECE
1351: @cindex $PIECE
1352: @cindex intrinsic functions, $PIECE
1353:
1354: @emph{Syntax}
1355:
1356: @code{$PIECE(@emph{s},@emph{d}[,@emph{n}[,@emph{end}]])}
1357:
1358: Accesses the @code{n}th through @code{end} @code{d}-delimited pieces of string @code{s}.
1359:
1360: The first argument is the string to be evaluated.
1361:
1362: The second argument is the delimiter to be used.
1363:
1364: The optional third argument is the first @code{d}-delimited piece to access, and defaults to @code{1}.
1365:
1366: The optional fourth argument is the final @code{d}-delimited piece to access, and defaults to the value of the third argument (@code{n}).
1367:
1368: Can be used on the left-hand side of an expression in order to @code{@ref{SET}} a value into a @code{d}-delimited piece of @code{s}, as in:
1369:
1370: @example
1.28 snw 1371: ; ^snw="this^is^a^piece"
1372: SET $PIECE(^snw,"^",2)="isn't" ; => "this^isn't^a^piece"
1.1 snw 1373: @end example
1374:
1375: @node $QLENGTH()
1376: @section $QLENGTH
1377: @cindex $QLENGTH
1378: @cindex intrinsic functions, $QLENGTH
1379:
1380: @emph{Syntax}
1381:
1382: @example
1383: @code{$QLENGTH(@emph{expr V glvn})}
1384: @end example
1385:
1386: Returns the number of subscripts in @emph{glvn}.
1387:
1388: @emph{Example}
1389: @example
1390: @code{SET SUBCT=$QLENGTH("^GBL(1,2,3)") ; => 3}
1391: @end example
1392:
1393: @node $QSUBSCRIPT()
1394: @section $QSUBSCRIPT
1395: @cindex $QSUBSCRIPT
1396: @cindex intrinsic functions, $QSUBSCRIPT
1397:
1398: @emph{Syntax}
1399:
1400: @example
1401: @code{$QSUBSCRIPT(@emph{expr V glvn},@emph{expr V n})}
1402: @end example
1403:
1.28 snw 1404: In the RHS form, returns the @emph{n}th subscript of @emph{glvn}.
1.1 snw 1405:
1406: @emph{Example}
1407:
1408: @example
1409: @code{SET SUB=$QSUBSCRIPT("^GBL(1,2,3)",2) ; => 2}
1410: @end example
1411:
1.28 snw 1412: @emph{Syntax}
1413:
1414: @example
1415: @code{SET $QSUBSCRIPT(@emph{expr V glvn},@emph{expr V n})=@emph{expr} ; => ^GBL(1,4,3)}
1416: @end example
1417:
1418: In the LHS form, sets the @emph{n}th subscript of @emph{glvn} to @emph{expr}.
1419:
1.1 snw 1420: @node $QUERY()
1421: @section $QUERY
1422: @cindex $QUERY
1423: @cindex intrinsic functions, $QUERY
1424:
1425: Returns the next subscripted reference in a global.
1426:
1427: @emph{Syntax}
1428:
1429: @example
1430: @code{$QUERY(@emph{glvn})}
1431: @end example
1432:
1433: @emph{Example}
1434:
1435: We will assume the following data structure exists:
1436: @example
1.28 snw 1437: ^snw(1)=1
1438: ^snw(1,2)="foo"
1439: ^snw(2)=3
1440: ^snw(3)=""
1.1 snw 1441: @end example
1442:
1.28 snw 1443: The following code will retrieve the next subscripted name after @code{^snw(1)}:
1.1 snw 1444:
1445: @example
1.28 snw 1446: @code{SET NEXTNAM=$QUERY(^snw(1)) ; => ^snw(1,2)}
1.1 snw 1447: @end example
1448:
1449: @node $RANDOM()
1450: @section $RANDOM
1451: @cindex $RANDOM
1452: @cindex intrinsic functions, $RANDOM
1453:
1454: @emph{Syntax}
1455:
1456: @example
1457: $RANDOM(@emph{max})
1458: @end example
1459:
1460: Returns a pseudo-random integer in the range of @code{0..@emph{max} - 1}
1461:
1462: @node $REVERSE()
1463: @section $REVERSE
1464: @cindex $REVERSE
1465: @cindex intrinsic functions, $REVERSE
1466:
1467: @emph{Syntax}
1468:
1469: @example
1470: $REVERSE(@emph{s})
1471: @end example
1472:
1473: Returns the reverse of string @emph{s}.
1474:
1475: @emph{Example}
1476:
1477: @example
1478: SET FOO=$REVERSE("ABC") ; => CBA
1479: @end example
1480:
1481: @node $SELECT()
1482: @section $SELECT
1483: @cindex $SELECT
1484: @cindex intrinsic functions, $SELECT
1485:
1486: Returns a value corresponding to the first true condition in a list of conditional expressions. Each argument is an expression, followed by a colon, followed by an expression whose value will be returned if the first expression is true. If no expressions are true, error condition @code{M4} is raised.
1487:
1488: @emph{Example}
1489:
1490: @example
1491: SET FOO=$SELECT(1=2:"math is broken",1=1:"the world makes sense") ; => "the world makes sense"
1492: @end example
1493:
1494: @node $STACK()
1495: @section $STACK
1496: @cindex $STACK
1497: @cindex intrinsic functions, $STACK
1498:
1499: Returns information about the program execution stack. The @code{$STACK} intrinsic function has both a one-argument form and a two-argument form.
1500:
1501: @emph{Syntax (One-Argument)}
1502:
1503: @example
1504: $STACK(@emph{<num>})
1505: @end example
1506:
1507: If @emph{num} is @code{0}, returns the command with which this FreeM instance was invoked.
1508:
1509: If @emph{num} is @code{-1}, returns the current program execution stack level.
1510:
1511: If @emph{num} represents a valid program execution stack depth above @code{0}, returns one of the following values indicating the reason for which the referenced program execution stack level was created:
1512:
1513: @table @asis
1514:
1515: @item @code{$$}
1516: If @code{$STACK(@emph{<num>})="$$"}, program execution stack level @code{num} was created as the result of an extrinsic function call
1517:
1518: @item @emph{<m-command>}
1519: If @code{$STACK(@emph{<num>})} returns a valid M command, the referenced program execution stack level was created as a result of the @emph{m-command} command.
1520:
1521: @end table
1522:
1523: @emph{Syntax (Two-Argument})
1524:
1525: @example
1526: $STACK(@emph{<num>},"[ECODE|MCODE|PLACE]")
1527: @end example
1528:
1529: Returns the error codes, M program code, or entryref applicable to the action that created program execution stack level @emph{num}.
1530:
1531: @node $TEXT()
1532: @section $TEXT
1533: @cindex $TEXT
1534: @cindex intrinsic functions, $TEXT
1535:
1536: Returns a line of code from a routine.
1537:
1538: @node $TRANSLATE()
1539: @section $TRANSLATE
1540: @cindex $TRANSLATE
1541: @cindex intrinsic functions, $TRANSLATE
1542:
1.25 snw 1543: Replaces characters in a string.
1544:
1545: The first argument is a string expression representing the text to be changed.
1546:
1547: The second argument is a list of characters to replace.
1548:
1549: The third argument is a list of characters to use as the replacements for the characters in the second argument.
1550:
1551: @emph{Example}
1552:
1553: @example
1554: DEFAULT.USER> W $TRANSLATE("twig","wt","rb")
1555: brig
1556: @end example
1557:
1.1 snw 1558: @node $TYPE()
1559: @section $TYPE
1560: @cindex $TYPE
1561: @cindex intrinsic functions, $TYPE
1562: @cindex object functions, $TYPE
1563:
1564: Returns a string giving the class of the object specified in the parameter.
1565:
1566: @xref{Object-Oriented Programming}
1567:
1568: @node $VIEW()
1569: @section $VIEW
1570: @cindex $VIEW
1571: @cindex intrinsic functions, $VIEW
1572:
1573: @node $ZBOOLEAN()
1574: @section $ZBOOLEAN
1575: @cindex $ZBOOLEAN
1576: @cindex intrinsic functions, $ZBOOLEAN
1577: @cindex intrinsic functions, implementation-specific
1578:
1579:
1580: Performs @emph{boolean-operation} on numeric arguments @emph{A} and @emph{B}.
1581:
1582: @emph{Syntax}
1583:
1584: @example
1585: SET RESULT=$ZBOOLEAN(@emph{A},@emph{B},@emph{boolean-operation})
1586: @end example
1587:
1588: @code{$ZBOOLEAN} Operations (@emph{boolean-operation} values)
1589:
1590: @table @code
1591: @item 0
1592: Always @emph{false}
1593: @item 1
1594: @code{A AND B}
1595: @item 2
1596: @code{A AND NOT B}
1597: @item 3
1598: @code{A}
1599: @item 4
1600: @code{NOT A AND B}
1601: @item 5
1602: @code{B}
1603: @item 6
1604: @code{A XOR B}
1605: @item 7
1606: @code{A OR B}
1607: @item 8
1608: @code{A NOR B}
1609: @item 9
1610: @code{A EQUALS B}
1611: @item 10
1612: @code{NOT B}
1613: @item 11
1614: @code{A OR NOT B}
1615: @item 12
1616: @code{NOT A}
1617: @item 13
1618: @code{NOT A OR B}
1619: @item 14
1620: @code{A NAND B}
1621: @item 15
1622: Always @emph{true}
1623: @end table
1624:
1625: @node $ZCALL()
1626: @section $ZCALL
1627: @cindex $ZCALL
1628: @cindex intrinsic functions, $ZCALL
1629: @cindex intrinsic functions, implementation-specific
1630:
1.26 snw 1631: Purpose unknown.
1632:
1.1 snw 1633: @node $ZCRC()
1634: @section $ZCRC
1635: @cindex $ZCRC
1636: @cindex intrinsic functions, $ZCRC
1637: @cindex intrinsic functions, implementation-specific
1638:
1639: Returns a checksum of @code{arg1}.
1640:
1641: @emph{Syntax}
1642:
1643: @code{$ZCRC(@emph{arg1})}
1644:
1645: @code{SET VAR=$ZCRC("MUMPS") ; => 86}
1646:
1647: @node $ZDATA()
1648: @section $ZDATA
1649: @cindex $ZDATA
1650: @cindex intrinsic functions, $ZDATA
1651: @cindex intrinsic functions, implementation-specific
1652:
1.26 snw 1653: Purpose unknown.
1654:
1.1 snw 1655: @node $ZDATE()
1656: @section $ZDATE
1657: @cindex $ZDATE
1658: @cindex intrinsic functions, $ZDATE
1659: @cindex intrinsic functions, implementation-specific
1660:
1661: Converts a @code{@ref{$HOROLOG}} string into a human-readable date.
1662:
1663: @emph{Syntax}
1664:
1665: @example
1666: SET VAR=$ZDATE($H[,@emph{<format-string>}])
1667: @end example
1668:
1669: The optional @emph{<format-string>} follows the same rules as the UNIX @code{strftime} function. If @emph{<format-string>} is omitted, the value of @code{^$SYSTEM("ZDATE_FORMAT")} is used (typically @code{%x}).
1670:
1671: @xref{^$SYSTEM}
1672:
1673: @node $ZEDIT()
1674: @section $ZEDIT
1675: @cindex $ZEDIT
1676: @cindex intrinsic functions, $ZEDIT
1677: @cindex intrinsic functions, implementation-specific
1678:
1.26 snw 1679: Purpose unknown.
1680:
1.1 snw 1681: @node $ZHOROLOG()
1682: @section $ZHOROLOG
1683: @cindex $ZHOROLOG
1684: @cindex intrinsic functions, $ZHOROLOG
1685: @cindex intrinsic functions, implementation-specific
1686:
1687: Converts date and/or time values producible by @code{@ref{$ZDATE()}} or @code{@ref{$ZTIME()}} to @code{@ref{$HOROLOG}} format.
1688:
1689: @emph{Syntax}
1690:
1691: @example
1692: $ZHOROLOG(@emph{<date-value>},@emph{<format-string>})
1693: @end example
1694:
1695: @emph{<date-value>} is a date or time string compatible with the formats from @code{@ref{$ZDATE()}} or @code{@ref{$ZTIME}}.
1696:
1697: @emph{<format-string>} is a format string of the same format as used by the @code{strptime(3)} UNIX function.
1698:
1699: @node $ZKEY()
1700: @section $ZKEY
1701: @cindex $ZKEY
1702: @cindex intrinsic functions, $ZKEY
1703: @cindex intrinsic functions, implementation-specific
1704:
1.26 snw 1705: Purpose unknown.
1706:
1.1 snw 1707: @node $ZLENGTH()
1708: @section $ZLENGTH
1709: @cindex $ZLENGTH
1710: @cindex intrinsic functions, $ZLENGTH
1711: @cindex intrinsic functions, implementation-specific
1712:
1.26 snw 1713: Purpose unknown.
1714:
1.1 snw 1715: @node $ZLSD()
1716: @section $ZLSD
1717: @cindex $ZLSD
1718: @cindex intrinsic functions, $ZLSD
1719: @cindex intrinsic functions, implementation-specific
1720:
1721: Returns the Levenshtein distance between two arguments. The Levenshtein distance represents the minimum number of edits needed to change the first argument into the second argument.
1722:
1723: @emph{Syntax}
1724:
1725: @code{SET VAR=$ZLSD(@emph{arg1},@emph{arg2})}
1726:
1727: @emph{Example}
1728:
1729: @code{SET VAR=$ZLSD("KITTENS","MITTENS") ; => 1}
1730:
1731: @node $ZM()
1732: @section $ZM
1733: @cindex $ZM
1734: @cindex intrinsic functions, $ZM
1735: @cindex intrinsic functions, implementation-specific
1736:
1.51 snw 1737: Purpose unknown.
1738:
1.1 snw 1739: @node $ZNAME()
1740: @section $ZNAME
1741: @cindex $ZNAME
1742: @cindex intrinsic functions, $ZNAME
1743: @cindex intrinsic functions, implementation-specific
1744:
1.26 snw 1745: Purpose unknown.
1746:
1.52 snw 1747: This function relies on the value of @code{$VIEW(71)} being @code{0} (this is not the default).
1748:
1.1 snw 1749: @node $ZNEXT()
1750: @section $ZNEXT
1751: @cindex $ZNEXT
1752: @cindex intrinsic functions, $ZNEXT
1753: @cindex intrinsic functions, implementation-specific
1754:
1.52 snw 1755: Returns a fully-formed variable reference of the next numeric subscript of the specified glvn.
1756:
1757: @emph{Syntax}
1758:
1759: @example
1760: $ZNEXT(@emph{glvn})
1761: @end example
1762:
1763: @emph{Example}
1764:
1765: Assume the following array:
1766:
1767: @example
1768: ^foo(1)=""
1769: ^foo(2)=""
1770: @end example
1771:
1772: And the following code:
1773:
1774: @example
1775: W $ZNEXT(^foo(1)) ; => ^foo(2)
1776: @end example
1777:
1778: This function relies on the value of @code{$VIEW(71)} being @code{1} (this is the default).
1.26 snw 1779:
1.1 snw 1780: @node $ZORDER()
1781: @section $ZORDER
1782: @cindex $ZORDER
1783: @cindex intrinsic functions, $ZORDER
1784: @cindex intrinsic functions, implementation-specific
1785:
1.26 snw 1786: Purpose unknown.
1787:
1.1 snw 1788: @node $ZPIECE()
1789: @section $ZPIECE
1790: @cindex $ZPIECE
1791: @cindex intrinsic functions, $ZPIECE
1792: @cindex intrinsic functions, implementation-specific
1793:
1.26 snw 1794: Purpose unknown.
1795:
1.1 snw 1796: @node $ZPREVIOUS()
1797: @section $ZPREVIOUS
1798: @cindex $ZPREVIOUS
1799: @cindex intrinsic functions, $ZPREVIOUS
1800: @cindex intrinsic functions, implementation-specific
1801:
1.26 snw 1802: Purpose unknown.
1803:
1.1 snw 1804: @node $ZREPLACE()
1805: @section $ZREPLACE
1806: @cindex $ZREPLACE
1807: @cindex intrinsic functions, $ZREPLACE
1808: @cindex intrinsic functions, implementation-specific
1809:
1810: Replaces all instances of @code{arg2} with @code{arg3} in string @code{arg1}.
1811:
1812: @emph{Syntax}
1813: @code{$ZREPLACE(@emph{arg1},@emph{arg2},@emph{arg3})}
1814:
1815: @emph{Example}
1816:
1817: @code{SET VAR=$ZREPLACE("CAT","C","B") ; => BAT}
1818:
1819: @node $ZSYNTAX()
1820: @section $ZSYNTAX
1821: @cindex $ZSYNTAX
1822: @cindex intrinsic functions, $ZSYNTAX
1823: @cindex intrinsic functions, implementation-specific
1824:
1825: @code{$ZSYNTAX} performs a very basic syntax check on @emph{expr V mcode}. Checks only for illegal commands, mismatched brackets, mismatched quotes, missing or surplus arguments, or surplus commas.
1826:
1827: @emph{Syntax}
1828: @example
1829: $ZSYNTAX(@emph{expr V mcode})
1830: @end example
1831:
1832: If no syntax error is found, returns the empty string.
1833:
1834: If a syntax error is found, returns a number indicating the position in @emph{expr V mcode} at which the error was found, followed by a comma, and the FreeM error code that was found.
1835:
1836: @node $ZTIME()
1837: @section $ZTIME
1838: @cindex $ZTIME
1839: @cindex intrinsic functions, $ZTIME
1840: @cindex intrinsic functions, implementation-specific
1841:
1842: Converts a @code{@ref{$HOROLOG}} string into a human-readable time.
1843:
1844: @emph{Syntax}
1845:
1846: @example
1847: SET VAR=$ZTIME($H[,@emph{<format-string>}])
1848: @end example
1849:
1850: The optional @emph{<format-string>} follows the same rules as the UNIX @code{strftime(3)} function. If @emph{<format-string>} is omitted, the value of @code{^$SYSTEM("ZTIME_FORMAT")} is used (typically @code{%X}).
1851:
1852: @node OBJECT Methods
1853: @chapter OBJECT Methods
1854:
1855: These methods are part of the @code{^%OBJECT} class, from which all FreeM objects ultimately inherit.
1856:
1857: Please note that classes may override @code{^%OBJECT} methods (or methods of any class) in order to provide results more fitting to the class's abstraction goals.
1858:
1859: @menu
1860: * $$TONUMBER:: Returns the canonical numeric representation of the object.
1861: * $$TYPE:: Returns the fully-qualified class name of the object.
1862: * $$VALUE:: Returns the value of the object.
1863: @end menu
1864:
1865: @node $$TONUMBER
1866: @section $$TONUMBER
1867:
1868: Returns (when applicable) a canonical numeric representation of the referenced object.
1869:
1870: @emph{Syntax}
1871:
1872: @example
1873: W $$MYOBJECT.TONUMBER(),!
1874: @end example
1875:
1876: If no canonical numeric representation of the object is possible, will return the empty string.
1877:
1878: @node $$TYPE
1879: @section $$TYPE
1880:
1881: Returns the fully-qualified class of the referenced object.
1882:
1883: @emph{Syntax}
1884:
1885: @example
1886: W $$MYOBJECT.TYPE()
1887: @end example
1888:
1889: Note that M variables that are created by non-object-oriented means will be objects of the @code{^%STRING} class.
1890:
1891: @node $$VALUE
1892: @section $$VALUE
1893:
1894: Returns the value of the referenced object.
1895:
1896: @emph{Syntax}
1897:
1898: @example
1899: W $$MYOBJECT.VALUE()
1900: @end example
1901:
1902: @node STRING Methods
1903: @chapter STRING Methods
1904:
1905: These are methods inherent to the @code{^%STRING} class, which is the default class for M variables created without specifying a class.
1906:
1907: @menu
1908: * $$ASCII:: Return the ASCII code of a character within the string.
1909: * $$DATA:: Return tree characteristics of the string.
1910: * $$DISTANCE:: Determine Levenstein distance between this string and another.
1911: * $$EXTRACT:: Return a substring of the string.
1912: * $$FIND:: Find the position of a substring within the string.
1913: * $$FNUMBER:: Format numbers.
1914: * $$JUSTIFY:: Pad the string to specific positions.
1915: * $$LENGTH:: Return the length of the string.
1916: * $$PIECECOUNT:: Return the count of pieces existing between instances of a delimiter.
1917: * $$PIECE:: Return a delimited subset of the string.
1918: * $$REPLACE:: Replace instances of a substring within the string.
1919: * $$REVERSE:: Reverse the order of characters in the string.
1920: * $$TOLOWER:: Return a lowercase version of the string.
1921: * $$TOUPPER:: Return an uppercase version of the string.
1922: * $$TRANSLATE:: Replace individual characters within the string.
1923: @end menu
1924:
1925: @node $$ASCII
1926: @section $$ASCII
1927:
1928: Returns the ASCII code of a character within the string. See @ref{$ASCII()}.
1929:
1930: @emph{Syntax}
1931:
1932: @example
1933: W $$MYOBJECT.ASCII(3)
1934: @end example
1935:
1936: The above example returns the ASCII code in position 3 of string object @code{MYOBJECT}.
1937:
1938: @node $$DATA
1939: @section $$DATA
1940:
1941: Returns the value of the @code{$DATA} intrinsic function as performed on the value of the object. See @ref{$DATA()}.
1942:
1943: @emph{Syntax}
1944:
1945: @example
1946: W $$MYOBJECT.DATA()
1947: @end example
1948:
1949: @node $$DISTANCE
1950: @section $$DISTANCE
1951:
1952: Returns the Levenstein distance between the string and another string. See @ref{$ZLSD()}.
1953:
1954: @emph{Syntax}
1955:
1956: @example
1957: W $$MYOBJECT.DISTANCE("someString")
1958: @end example
1959:
1960: @node $$EXTRACT
1961: @section $$EXTRACT
1962:
1963: Returns a substring of the string. See @ref{$EXTRACT()}.
1964:
1965: @emph{Syntax}
1966:
1967: @example
1968: $$<objectName>.EXTRACT(<start>,<end>)
1969: @end example
1970:
1971:
1972: @node $$FIND
1973: @section $$FIND
1974:
1.25 snw 1975: Finds the character immediately following the first occurence of a substring within a string.
1976:
1977: The first argument is the substring to be located.
1978:
1979: The second argument is the position within the string at which to begin searching.
1980:
1981: See @ref{$FIND()}.
1982:
1.1 snw 1983: @node $$FNUMBER
1984: @section $$FNUMBER
1985:
1.25 snw 1986: Formats a number according to a set of formatting codes.
1987:
1988: The argument is a series of formatting codes. See @ref{$FNUMBER()} for details.
1989:
1.1 snw 1990: @node $$JUSTIFY
1991: @section $$JUSTIFY
1992:
1.25 snw 1993: Right-justifies a string based on a specified fixed length.
1994:
1995: The first argument is the character length of the output.
1996:
1997: The second argument controls the number of fractional digits to be included in the output, and defaults to the number of digits specified in the first argument.
1998:
1999: See @ref{$JUSTIFY()} for details.
2000:
1.1 snw 2001: @node $$LENGTH
2002: @section $$LENGTH
2003:
1.25 snw 2004: Returns the length of the string.
2005:
1.1 snw 2006: @node $$PIECECOUNT
2007: @section $$PIECECOUNT
2008:
1.25 snw 2009: Returns the number of items in a list delimited by the character specified in the argument.
2010:
1.1 snw 2011: @node $$PIECE
2012: @section $$PIECE
2013:
1.25 snw 2014: @emph{Syntax}
2015:
2016: @code{$PIECE(@emph{d}[,@emph{n}[,@emph{end}]])}
2017:
2018: Accesses the @code{n}th through @code{end} @code{d}-delimited pieces of the string.
2019:
2020: The first argument is the delimiter to be used.
2021:
2022: The optional second argument is the first @code{d}-delimited piece to access, and defaults to @code{1}.
2023:
2024: The optional third argument is the final @code{d}-delimited piece to access, and defaults to the value of the third argument (@code{n}).
2025:
2026:
1.1 snw 2027: @node $$REPLACE
2028: @section $$REPLACE
2029:
1.25 snw 2030: @emph{Syntax}
2031: @code{myString.$$REPLACE(@emph{arg1},@emph{arg2})}
2032:
2033: Replaces all instances of @code{arg2} with @code{arg3} in @code{myString}.
2034:
1.1 snw 2035: @node $$REVERSE
2036: @section $$REVERSE
2037:
1.25 snw 2038: Returns the reverse of the string.
2039:
1.1 snw 2040: @node $$TOLOWER
2041: @section $$TOLOWER
2042:
1.25 snw 2043: Returns an all-lowercase version of the string.
2044:
1.1 snw 2045: @node $$TOUPPER
2046: @section $$TOUPPER
2047:
1.25 snw 2048: Returns an all-uppercase version of the string.
2049:
1.1 snw 2050: @node $$TRANSLATE
2051: @section $$TRANSLATE
2052:
1.25 snw 2053: Identical to @ref{$TRANSLATE()}, except that the arguments are shifted left by one, and the input string is implicit (the object).
2054:
1.1 snw 2055: @node Commands
2056: @chapter Commands
2057: @cindex commands
2058:
2059: @menu
2060: * @@:: Execute the following expression as M code.
2061: * !:: Run an external program or command.
2062: * !!:: Launch a subshell from FreeM direct mode.
2063: * ABLOCK:: Increment the block counter for one or more event classes.
2064: * ASTART:: Enable asynchronous event handling for one or more event classes.
2065: * ASTOP:: Disable asynchronous event handling for one or more event classes.
2066: * AUNBLOCK:: Decrement the block counter for one or more event classes.
2067: * BREAK:: Interrupt a running routine to allow interactive debugging.
2068: * CLOSE:: Close an input/output device.
2069: * DO:: Transfer program control to one or more subroutines or introduces a new execution level.
2070: * ELSE:: Execute the remainder of a line if @code{@ref{$TEST}} evaluates @emph{false}.
2071: * FOR:: Repeat execution of a line or block of code.
2072: * GOTO:: Unconditionally transfer program execution to a supplied @emph{entryref}.
2073: * HALT:: Terminate the current FreeM interpreter instance.
2074: * HANG:: Temporarily suspend the running program.
2075: * IF:: Execute the remainder of a line if a conditional expression evaluates @emph{true}.
2076: * JOB:: Execute an @emph{entryref} in a child process.
2077: * KILL:: Remove data from a local, global, or structured system variable.
2078: * KSUBSCRIPTS:: Kill only the descendant subscripts of a local, global, global, or structured system variable.
2079: * KVALUE:: Kill only the value of a local, global, or structured system variable.
2080: * LOCK:: Control advisory locking for concurrency control.
2081: * MERGE:: Merge contents of one local, global, or structured system variable into another.
2082: * NEW:: Introduce a new scope for a specified local variable or intrinsic special variable or instantiate an object.
2083: * OPEN:: Open a sequential or socket input/output device.
2084: * QUIT:: End execution of the current process level, optionally with return value.
2085: * READ:: Read input from an input/output device.
2086: * SET:: Set the value of a local variable, global, intrinsic special variable, or structured system variable.
2087: * TCOMMIT:: Commit a transaction.
2088: * THEN:: Preserve @code{@ref{$TEST}} until the end of the current line.
2089: * TROLLBACK:: Roll back all pending transactions.
2090: * TSTART:: Introduce a new transaction processing level.
2091: * USE:: Set the currently-active input/output device.
2092: * VIEW:: Modify FreeM internal parameters.
2093: * WRITE:: Write output to current input/output device.
2094: * XECUTE:: Interpret string as M code.
1.46 snw 2095: * ZASSERT:: Raise error when a conditional expression evaluates @emph{false}.
1.48 snw 2096: * ZBREAK:: Enable/disable ZBREAK mode.
1.42 snw 2097: * ZCONST:: Define a constant that cannot be altered after initial definition.
1.48 snw 2098: * ZGOTO:: @code{GOTO} with @code{BREAK} control.
1.49 snw 2099: * ZHALT:: Exit FreeM job with return value.
1.1 snw 2100: * ZINSERT:: Insert code into routine buffer.
1.49 snw 2101: * ZJOB:: Invoke job, ignoring any timeouts.
1.1 snw 2102: * ZLOAD:: Load routine into routine buffer.
1.42 snw 2103: * ZMAP:: Map a global name to a non-default namespace.
1.1 snw 2104: * ZNEW:: Unknown.
2105: * ZPRINT:: Print contents of routine buffer.
1.49 snw 2106: * ZQUIT:: Quit multiple stack levels at once.
1.1 snw 2107: * ZREMOVE:: Remove code from routine buffer.
2108: * ZSAVE:: Save routine buffer to disk.
1.42 snw 2109: * ZTHROW:: Programmatically raise an error condition.
1.50 snw 2110: * ZTRAP:: Raise a FreeM error.
1.42 snw 2111: * ZUNMAP:: Remove a mapping of a global to a non-default namespace.
2112: * ZWATCH:: Enable or disable watchpoints, or set or clear watchpoints on specified globals, locals, or structured system variables.
2113: * ZWITH:: Set prefix for future variable references.
1.1 snw 2114: * ZWRITE:: Write local variable, global, or structured system variable to @code{@ref{$IO}}.
2115: @end menu
2116:
2117: @node @@
2118: @section @@
2119: @cindex @@
2120: @cindex commands, @@
2121: @cindex commands, implementation-specific
2122: @cindex commands, non-standard
2123:
2124: Executes FreeM code @emph{expr V mcode}.
2125:
2126: @emph{Syntax}
2127:
2128: @example
2129: @@@emph{expr V mcode}
2130: @end example
2131:
2132: @emph{Example (Using Variable)}
2133:
2134: @example
1.22 snw 2135: DEFAULT.USER> SET FOO="WRITE ""HELLO WORLD"",!"
2136: DEFAULT.USER> @@FOO
1.1 snw 2137:
2138: HELLO WORLD
2139:
1.22 snw 2140: DEFAULT.USER>
1.1 snw 2141: @end example
2142:
2143: @emph{Example (Using String Literal)}
2144:
2145: @example
1.22 snw 2146: DEFAULT.USER> @@"WRITE ""HELLO WORLD"",!"
1.1 snw 2147:
2148: HELLO WORLD
2149:
1.22 snw 2150: DEFAULT.USER>
1.1 snw 2151: @end example
2152:
2153: @emph{Example (Using Indirection)}
2154:
2155: @example
1.22 snw 2156: DEFAULT.USER> SET FOO="BAR"
1.1 snw 2157:
1.22 snw 2158: DEFAULT.USER> SET BAR="WRITE ""HELLO WORLD"",!"
1.1 snw 2159:
1.22 snw 2160: DEFAULT.USER> @@@@FOO
1.1 snw 2161:
2162: HELLO WORLD
2163:
1.22 snw 2164: DEFAULT.USER>
1.1 snw 2165: @end example
2166:
2167:
2168: @node !
2169: @section !
2170: @cindex !
2171: @cindex commands, !
2172: @cindex commands, external
2173: @cindex commands, non-standard
2174: @emph{FreeM Extension}
2175:
2176: Invokes a shell to run @emph{<external-command>} from within FreeM. This temporarily disables @command{SIGALRM} handling in FreeM, which may interrupt the use of event-driven M programming commands including @command{ESTART} and @command{ESTOP}.
2177:
2178: If the @command{<} character is supplied immediately preceding @emph{<external-command>}, FreeM will append the contents of M local variable @code{%} to @emph{<external-command>} as standard input.
2179:
2180: If the @command{>} character is supplied immediately preceding @emph{<external-command>}, FreeM will take the standard output stream of @emph{<external-command>} and store it in M local variable @code{%}.
2181:
2182: @code{%} contains the number of lines in the input or output. @code{%(1)..%(@emph{n})} contains the data for lines 1-@emph{n}.
2183:
2184: @node !!
2185: @section !!
2186: @cindex !!
2187: @cindex commands, !!
2188: @cindex commands, external
2189: @cindex commands, non-standard
2190: @emph{FreeM Extension}
2191:
2192: Launches a subshell within the FreeM direct mode, allowing the user to run operating system commands.
2193:
2194: @example
1.22 snw 2195: DEFAULT.USER> !!
1.1 snw 2196:
2197: Type Ctrl-D to exit from the shell
2198: $ uname -a
2199: Linux hesperos 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux
2200: $ exit
2201:
1.22 snw 2202: DEFAULT.USER>
1.1 snw 2203: @end example
2204:
2205:
2206: @node ABLOCK
2207: @section ABLOCK
2208: @cindex ABLOCK
2209: @cindex commands, ABLOCK
2210:
2211: Increments the event block counter for one or more event classes. While the block counter for an event class is greater than zero, registered event handlers for that event class will not execute, and will instead be queued for later execution once the block counter reaches zero (all blocks removed).
2212:
2213: An implicit @code{ABLOCK} on all event classes occurs when an event handler subroutine is executing. As soon as a @code{QUIT} is reached within an event handler, an implicit @code{ABLOCK} will occur.
2214:
2215: @emph{Syntax}
2216:
2217: @example
2218: ABLOCK@emph{:postcondition}
2219: @end example
2220:
2221: In its argumentless form, @code{ABLOCK} increments the block counter for @emph{all} event classes, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2222:
2223: @example
2224: ABLOCK@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2225: @end example
2226:
2227: In its inclusive form, @code{ABLOCK} increments the block counters for all event classes named in the list, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2228:
2229: @example
2230: ABLOCK@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN}
2231: @end example
2232:
2233: In its exclusive form, @code{ABLOCK} increments the block counters for all event classes @emph{except for} those named in the list, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2234:
2235:
2236: @node ASTART
2237: @section ASTART
2238: @cindex ASTART
2239: @cindex commands, ASTART
2240:
2241: Enables asynchronous event handling for one or more event classes.
2242:
2243: @emph{Syntax}
2244:
2245: @example
2246: ASTART@emph{:postcondition}
2247: @end example
2248:
2249: In its argumentless form, @code{ASTART} enables asynchronous event handling for all event classes, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2250:
2251: @example
2252: ASTART@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2253: @end example
2254:
2255: In its inclusive form, @code{ASTART} enables asynchronous event handling for all event classes named in the list, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2256:
2257: @example
2258: ASTART@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN})
2259: @end example
2260:
2261: In its exclusive form, @code{ASTART} enables asynchronous event handling for all event classes @emph{except for} those named in the list, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2262:
2263: @node ASTOP
2264: @section ASTOP
2265: @cindex ASTOP
2266: @cindex commands, ASTOP
2267:
2268: Disables asynchronous event handling for one or more event classes.
2269:
2270: @emph{Syntax}
2271:
2272: @example
2273: ASTOP@emph{:postcondition}
2274: @end example
2275:
2276: In its argumentless form, @code{ASTOP} disables asynchronous event handling for all event classes, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2277:
2278: @example
2279: ASTOP@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2280: @end example
2281:
2282: In its inclusive form, @code{ASTOP} disables asynchronous event handling for all event classes named in the list, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2283:
2284: @example
2285: ASTOP@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN})
2286: @end example
2287:
2288: In its exclusive form, @code{ASTOP} disables asynchronous event handling for all event classes @emph{except for} those named in the list, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2289:
2290: @node AUNBLOCK
2291: @section AUNBLOCK
2292: @cindex AUNBLOCK
2293: @cindex commands, AUNBLOCK
2294:
2295: Decrements the event block counter for one or more event classes.
2296:
2297: @emph{Syntax}
2298:
2299: @example
2300: AUNBLOCK@emph{:postcondition}
2301: @end example
2302:
2303: In its argumentless form, @code{AUNBLOCK} decrements the block counter for @emph{all} event classes, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2304:
2305: @example
2306: AUNBLOCK@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2307: @end example
2308:
2309: In its inclusive form, @code{AUNBLOCK} decrements the block counters for all event classes named in the list, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2310:
2311: @example
2312: AUNBLOCK@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN}
2313: @end example
2314:
2315: In its exclusive form, @code{AUNBLOCK} decrements the block counters for all event classes @emph{except for} those named in the list, provided the optional @emph{postcondition} is either @emph{true} or omitted.
2316:
2317:
2318: @node BREAK
2319: @section BREAK
2320: @cindex BREAK
2321: @cindex commands, BREAK
2322:
2323: Interrupts running routine to allow interactive debugging.
2324:
2325: @emph{Syntax}
2326:
2327: @example
2328: @code{BREAK@emph{:postcondition}}
2329: @end example
2330:
2331: In its argumentless form, @code{BREAK} suspends execution of running code, provided the optional @emph{postcondition} is @emph{true} or omitted.
2332:
2333: @example
2334: @code{BREAK@emph{:postcondition} @emph{breakflag}}
2335: @end example
2336:
2337: @emph{FreeM Extension}
2338:
1.35 snw 2339: In its single-argument form, @code{BREAK} enters the interactive debugger or sets @emph{Ctrl-C} handling and error handling characteristics, provided the optional @emph{postcondition} is @emph{true} or omitted.
1.1 snw 2340: The following table enumerates the possible values of @emph{breakflag}
2341:
2342: @table @code
1.35 snw 2343: @item "DEBUG"
2344: Enters the interactive debugger
1.1 snw 2345: @item 0
2346: Disables @emph{Ctrl-C} handling
2347: @item -2
2348: Enables normal FreeM error handling
2349: @item 2
2350: Enables @emph{Digital Standard MUMPS} v2 error handling
2351: @item @emph{any integer value other than 0, 2, or -2}
2352: Enables @emph{Ctrl-C} handling
2353: @end table
2354:
2355: @node CLOSE
2356: @section CLOSE
2357: @cindex CLOSE
2358: @cindex commands, CLOSE
2359:
2360: Closes an input/output device.
2361:
2362: @emph{Syntax}
2363:
2364: @example
2365: @code{CLOSE@emph{:postcondition}}
2366: @end example
2367:
2368: In its argumentless form, @code{CLOSE} closes all I/O devices except for device 0 (the @code{HOME} device), provided the optional @emph{postcondition} is @emph{true} or omitted.
2369:
2370: @example
2371: @code{CLOSE@emph{:postcondition} @emph{channel}}
2372: @end example
2373:
2374: In its single-argument form, @code{CLOSE} closes the I/O device associated with channel @emph{channel}, provided that @emph{channel} represents a currently-open device, and the optional @emph{postcondition} is @emph{true} or omitted.
2375:
2376: @node DO
2377: @section DO
2378: @cindex DO
2379: @cindex commands, DO
2380:
2381: In its inclusive form, transfers program control to one or more specified subroutines, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. Line levels of entryrefs specified in the argument list must be one, or error @code{M14} is raised.
2382:
2383: @emph{Syntax}
2384:
2385: @example
2386: DO[@emph{:postcondition}] @emph{entryref}[@emph{:postcondition}[,...]]
2387: @end example
2388:
1.35 snw 2389: @cartouche
2390: @quotation
2391: @emph{Non-Standard Behavior}
2392:
2393: FreeM allows @code{DO} @emph{entryref}s to follow the format of @code{+@emph{intexpr}}. In this case, the value of @emph{intexpr} will be interpreted as an offset from the first line of the current routine.
2394: @end quotation
2395: @end cartouche
2396:
1.1 snw 2397: In its argumentless form, transfers control to the following block of code where the line level is one greater than the level at which @code{DO} was encountered, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2398:
2399: @emph{Syntax}
2400:
2401: @example
2402: DO[@emph{:postcondition}]
2403: @end example
2404:
2405: @node ELSE
2406: @section ELSE
2407: @cindex ELSE
2408: @cindex commands, ELSE
2409:
2410: Executes the remainder of the line of code on which @code{ELSE} is encountered only if @code{$TEST} evaluates to @emph{false}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2411:
2412: @emph{Syntax}
2413:
2414: @example
2415: ELSE[@emph{:postcondition}]
2416: @end example
2417:
2418: @cartouche
2419: @quotation
2420: @emph{Non-Standard Behavior}
2421:
1.39 snw 2422: FreeM allows a @emph{postcondition} on @code{ELSE}. While explicitly forbidden in the @emph{Standard}, it was decided that FreeM should allow postconditions everywhere, both for the sake of foolish consistency (the likes of which Emerson warned against), and for the benefit of entrants to a hypothetical future obfuscated M contest, and those with a Machiavellian predisposition to wicked perversions and undue cleverness.
1.1 snw 2423:
1.35 snw 2424: Using postconditions on @code{ELSE} should be strictly avoided in production code, as they have no practical use, and may contribute to technical debt, hardening of the arteries, hobgoblins, a small mind, a surfeit of logic, climate change, @emph{Daily WTF} rants, or the meltdown of global financial markets.
1.1 snw 2425: @end quotation
2426: @end cartouche
2427:
2428: @node FOR
2429: @section FOR
2430: @cindex FOR
2431: @cindex commands, FOR
2432:
2433: In its argumentless form, repeatedly executes the remainder of the line on which @code{FOR} was encountered until a @code{QUIT}, @code{GOTO}, or end-of-line is encountered, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2434:
2435: @emph{Syntax}
2436:
2437: @example
2438: FOR[@emph{:postcondition}]
2439: @end example
2440:
2441: @cartouche
2442: @quotation
2443: @emph{Non-Standard Behavior}
2444:
2445: When @code{$DIALECT} is set to @code{FREEM}, FreeM allows a @emph{postcondition} on @code{FOR}. Much like postconditions on @code{ELSE} and @code{IF}, this is explicitly forbidden in the @emph{standard}. The expression contained in the @emph{postcondition} is evaluated on each iteration of the @code{FOR} loop, and if it does not evaluate @emph{true}, the loop will be immediately exited. The effect is roughly similar to @code{WHILE} constructs present in other languages, but absent from standard M.
2446:
2447: As with all non-standard features of FreeM, please exercise caution when using this feature, especially in code that is expected to run in other, less preternaturally-inclined M implementations.
2448: @end quotation
2449: @end cartouche
2450:
2451: In its sentinel form, repeatedly executes the remainder of the line and sets a sentinel variable on each iteration, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2452:
2453: On the first iteration of the loop, @emph{glvn} will be set to @emph{initalizer-expression}. On each subsequent iteration, @emph{glvn} will be incremented by @emph{increment-expression}, and the loop will terminate when @emph{glvn} meets or exceeds the value of @emph{max-expression}.
2454:
2455: @emph{Syntax}
2456:
2457: @example
2458: FOR[@emph{:postcondition}] @emph{glvn}=@emph{initializer-expression}:@emph{increment-expression}:@emph{max-expression}
2459: @end example
2460:
2461: @emph{Example}
2462:
2463: @example
1.22 snw 2464: DEFAULT.USER> FOR I=1:1:10 WRITE I,!
1.1 snw 2465:
2466: 1
2467: 2
2468: 3
2469: 4
2470: 5
2471: 6
2472: 7
2473: 8
2474: 9
2475: 10
2476:
1.22 snw 2477: DEFAULT.USER> FOR I=2:2:10 WRITE I,!
1.1 snw 2478:
2479: 2
2480: 4
2481: 6
2482: 8
2483: 10
2484: @end example
2485:
2486: In its explicit parameter form, a variable is set to each of a series of explicit values, once per iteration, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. The loop terminates when no more values are available.
2487:
2488: @emph{Syntax}
2489:
2490: @example
2491: FOR[@emph{:postcondition}] @emph{glvn}=@emph{expr1}[,..@emph{exprN}]
2492: @end example
2493:
2494: @emph{Example}
2495:
2496: @example
1.22 snw 2497: DEFAULT.USER> FOR I=60,"FOO",-3,"George",1450,$HOROLOG WRITE I,!
1.1 snw 2498:
2499: 60
2500: FOO
2501: -3
2502: George
2503: 1450
2504: 66106,52388
2505: @end example
2506:
2507: @node GOTO
2508: @section GOTO
2509: @cindex GOTO
2510: @cindex commands, GOTO
2511:
2512: Transfers program execution to another line of code, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. Attempting to @code{GOTO} a different line level or a different block when the line level of @code{GOTO} is greater than one will raise error @code{M45}.
2513:
2514: @emph{Syntax}
2515:
2516: @example
2517: GOTO[@emph{:postcondition}] @emph{entryref}
2518: @end example
2519:
1.35 snw 2520: @cartouche
2521: @quotation
2522: @emph{Non-Standard Behavior}
2523:
2524: FreeM allows @code{GOTO} @emph{entryref}s to follow the format of @code{+@emph{intexpr}}. In this case, the value of @emph{intexpr} will be interpreted as an offset from the first line of the current routine.
2525: @end quotation
2526: @end cartouche
2527:
2528:
1.1 snw 2529: @node HALT
2530: @section HALT
2531: @cindex HALT
2532: @cindex commands, HALT
2533:
2534: Halts program execution and frees resources allocated during execution, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2535:
2536: @emph{Syntax}
2537:
2538: @example
2539: HALT[@emph{:postcondition}]
2540: @end example
2541:
2542: @node HANG
2543: @section HANG
2544: @cindex HANG
2545: @cindex commands, HANG
2546:
2547: Temporarily suspends the program for @emph{expr} seconds, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. Values of @emph{expr} that are zero or less than zero are ignored.
2548:
2549: @emph{Syntax}
2550:
2551: @example
2552: HANG[@emph{:postcondition}] @emph{expr}
2553: @end example
2554:
2555: @cartouche
2556: @quotation
2557: @emph{Non-Standard Behavior}
2558:
2559: FreeM supports sub-second values for @emph{expr}.
2560: @end quotation
2561: @end cartouche
2562:
2563: @node IF
2564: @section IF
2565: @cindex IF
2566: @cindex commands, IF
2567:
2568: In its argumented form, allows the remainder of the line of code following @code{IF} to execute only if all @emph{tvexpr}s evaluate to @emph{true}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2569:
2570: @emph{Syntax}
2571: @example
2572: IF[@emph{:postcondition}] @emph{tvexpr}[,...@emph{tvexpr}]
2573: @end example
2574:
2575: In its argumentless form, allows the remainder of the line of code following @code{IF} to execute only if @code{$TEST} evaluates to @emph{1}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2576:
1.39 snw 2577:
1.1 snw 2578: @emph{Syntax}
2579: @example
1.39 snw 2580: IF[@emph{:postcondition}] @emph{command...}
1.1 snw 2581: @end example
2582:
1.39 snw 2583: @cartouche
2584: @quotation
2585: @emph{Style Recommendation}
2586:
2587: In the interest of readability and maintainability, we recommend avoiding the argumentless form of @code{IF} in new code. It is an obsolete relic of an era when routine sizes were severely limited, and can be difficult to spot, as the use of whitespace (@code{IF @emph{command}}) makes the intent of its use non-obvious at a glance. It is also far too easy to inadvertently delete the extra space, leading to program errors easily avoided otherwise.
2588:
2589: We recommend explicitly checking the value of @code{$TEST} instead, as in @code{IF $TEST @emph{command}} or @code{@emph{command}:$TEST ...}, as this makes the intent immediately clear both to M newcomers and seasoned experts, and sacrifices nothing of value, even on the oldest computer systems where FreeM can be used today.
2590: @end quotation
2591: @end cartouche
2592:
1.1 snw 2593: @node JOB
2594: @section JOB
2595: @cindex JOB
2596: @cindex commands, JOB
2597:
2598: Executes @emph{entryref} in a separate process, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2599:
2600: @emph{Syntax}
2601: @example
2602: JOB[@emph{:postcondition}] @emph{entryref}[:@emph{job-parameters}[:@emph{timeout}]]
2603: @end example
2604:
2605: If @emph{timeout} is supplied, FreeM will set @code{$TEST} to @emph{1} if the child process completes within @emph{timeout} seconds.
2606:
2607: @node KILL
2608: @section KILL
2609: @cindex KILL
2610: @cindex commands, KILL
2611:
2612: In its inclusive form, @code{KILL} deletes the specified @emph{glvn}s and their descendant subscripts, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2613:
2614: @emph{Syntax}
2615: @example
2616: KILL[@emph{:postcondition}] @emph{glvn}[,...@emph{glvn}]
2617: @end example
2618:
2619: In its exclusive form, @code{KILL} deletes all local variables @emph{except} for those specified by @emph{lvn}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2620:
2621: @emph{Syntax}
2622: @example
2623: KILL[@emph{:postcondition}] (@emph{lvn}[,...@emph{lvn}])
2624: @end example
2625:
2626: In its argumentless form, @code{KILL} deletes all local variables, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2627:
2628: @emph{Syntax}
2629: @example
2630: KILL[@emph{:postcondition}]
2631: @end example
2632:
2633: @node KSUBSCRIPTS
2634: @section KSUBSCRIPTS
2635: @cindex KSUBSCRIPTS
2636: @cindex commands, KSUBSCRIPTS
2637:
2638: Kills only the descendant subscripts (but not the data value) of a referenced global, local, or SSVN (where allowed).
2639:
2640: @emph{Syntax}
2641:
2642: @example
2643: KSUBSCRIPTS@emph{:postcondition} @emph{var1},...
2644: @end example
2645:
2646: In the above @emph{inclusive} form, @code{KVALUE} will kill the descendant subscripts at each local, global, or SSVN node specified in the list (provided that the optional @emph{postcondition} is @emph{true} or omitted), but will leave the data value intact.
2647:
2648: @cartouche
2649: @quotation
2650: @emph{Note}
1.54 ! snw 2651: The below @emph{argumentless} and @emph{exclusive} forms of @code{KSUBSCRIPTS} are not implemented in FreeM, as of version 0.64.0, but are planned for a future release.
1.1 snw 2652: @end quotation
2653: @end cartouche
2654:
2655: @example
2656: KSUBSCRIPTS@emph{:postcondition}
2657: @end example
2658:
2659: In the above @emph{argumentless} form, @code{KSUBSCRIPTS} will kill the descendant subscripts at the root of each local variable (provided that the optional @emph{postcondition} is @emph{true} or omitted), but will leave data values intact.
2660:
2661: @example
2662: KSUBSCRIPTS@emph{:postcondition} (@emph{var1},...)
2663: @end example
2664:
2665: In the above @emph{exclusive} form, @code{KSUBSCRIPTS} will kill the descendant subscripts of all local variables, @emph{with the exception of} those named in the list, provided that the optional @emph{postcondition} is @emph{true} or omitted, while leaving their data values intact.
2666:
2667:
2668: @node KVALUE
2669: @section KVALUE
2670: @cindex KVALUE
2671: @cindex commands, KVALUE
2672:
2673: Kills only the data value (but not descendant subscripts) of a referenced global, local, or SSVN (where allowed).
2674:
2675: @emph{Syntax}
2676:
2677: @example
2678: KVALUE@emph{:postcondition} @emph{var1},...
2679: @end example
2680:
2681: In the above @emph{inclusive} form, @code{KVALUE} will kill the data values at each local, global, or SSVN node specified in the list (provided that the optional @emph{postcondition} is @emph{true} or omitted), but will leave descendant subscripts intact.
2682:
2683: @cartouche
2684: @quotation
2685: @emph{Note}
1.54 ! snw 2686: The below @emph{argumentless} and @emph{exclusive} forms of @code{KVALUE} are not implemented in FreeM, as of version 0.64.0, but are planned for a future release.
1.1 snw 2687: @end quotation
2688: @end cartouche
2689:
2690: @example
2691: KVALUE@emph{:postcondition}
2692: @end example
2693:
2694: In the above @emph{argumentless} form, @code{KVALUE} will kill the data values at the root of each local variable (provided that the optional @emph{postcondition} is @emph{true} or omitted), but will leave descendant subscripts intact.
2695:
2696: @example
2697: KVALUE@emph{:postcondition} (@emph{var1},...)
2698: @end example
2699:
2700: In the above @emph{exclusive} form, @code{KVALUE} will kill the data values of all local variables, @emph{with the exception of} those named in the list, provided that the optional @emph{postcondition} is @emph{true} or omitted, while leaving their descendant subscripts intact.
2701:
2702: @node LOCK
2703: @section LOCK
2704: @cindex LOCK
2705: @cindex commands, LOCK
2706:
2707: Acquires or releases ownership of names.
2708:
2709: In its argumentless form, @code{LOCK} releases ownership of all names previously locked by the current process, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2710:
2711: @emph{Syntax}
2712: @example
2713: LOCK[@emph{:postcondition}]
2714: @end example
2715:
2716: In its incremental form, increments or decrements the lock counter for each specified @emph{name}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. Ownership of each @emph{name} is considered to be the current process as long as the lock counter for @emph{name} is greater than zero. If @emph{timeout} is specified, FreeM will wait no more than @emph{timeout} seconds in attempting to acquire ownership of @emph{name}.
2717:
2718: If @code{LOCK} succeeds within @emph{timeout}, @code{$TEST} is set to @emph{1}. Otherwise, @code{$TEST} is set to @emph{0}.
2719:
2720: @emph{Syntax}
2721: @example
2722: LOCK[@emph{:postcondition}] [+|-]@emph{name}[:@emph{timeout}][,...[+|-]@emph{name}[:@emph{timeout}]]
2723: @end example
2724:
2725: @emph{Example}
2726:
1.26 snw 2727: This example will increment the lock counter for @code{^SNW} and decrement the lock counter for @code{^MJR}.
1.1 snw 2728:
2729: @example
1.26 snw 2730: LOCK +^SNW,-^MJR
1.1 snw 2731: @end example
2732:
2733: In its non-incremental form, @code{LOCK} releases all @code{LOCK}s held by the current process, and then attempts to acquire a lock on each @emph{name}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. If @emph{timeout} is supplied, FreeM will attempt to lock @emph{name} for no more than @emph{timeout} seconds.
2734:
2735: If @code{LOCK} succeeds within @emph{timeout}, @code{$TEST} is set to @emph{1}. Otherwise, @code{$TEST} is set to @emph{0}.
2736:
2737: @emph{Syntax}
2738: @example
2739: LOCK[@emph{:postcondition}] @emph{name}[:@emph{timeout}][,...@emph{name}[:@emph{timeout}]]
2740: @end example
2741:
2742: @node MERGE
2743: @section MERGE
2744: @cindex MERGE
2745: @cindex commands, MERGE
2746:
2747: Merges the contents of one global, local, or SSVN subtree to another global, local, or SSVN.
2748:
2749: @emph{Syntax}
2750:
2751: @example
2752: @code{MERGE A=^$JOB}
2753: @end example
2754:
2755: The above example will merge the @code{^$JOB} SSVN into the @code{A} local. Note that the FreeM implementation of @code{MERGE} does not yet support multiple merge arguments. Returns error @code{M19} if either the source or the target variable are descendants of each other.
2756:
2757: @node NEW
2758: @section NEW
2759: @cindex NEW
2760: @cindex commands, NEW
2761:
2762: In all forms of @code{NEW}, @emph{name} must be a local variable name or @code{NEW}-able structured or intrinsic system variable.
2763:
2764: In its inclusive form, @code{NEW} saves each specified @emph{name} on the process stack and removes it, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. When the current stack frame is exited, the previous values are restored.
2765:
2766: @emph{Syntax}
2767:
2768: @example
2769: NEW[@emph{:postcondition}] @emph{name}[,...@emph{name}]
2770: @end example
2771:
2772: In its exclusive form, @code{NEW} saves all local variables @emph{except} those named (each @emph{name}) and removes them, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. When the current stack frame is exited, the previous values are restored.
2773:
2774: @emph{Syntax}
2775: @example
2776: NEW[@emph{:postcondition}] (@emph{name}[,...@emph{name}])
2777: @end example
2778:
2779: In its argumentless form, @code{NEW} saves all local variables and removes them, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. When the current stack frame is exited, the previous values are restored.
2780:
2781: @emph{Syntax}
2782: @example
2783: NEW@emph{:postcondition} @emph{name}=@emph{expr}
2784: @end example
2785:
2786: In its initializing form, @code{NEW} stacks variable @emph{name} and sets its value to @emph{expr}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. When the current stack frame is exited, the previous value is restored.
2787:
1.26 snw 2788: @emph{Syntax}
2789: @example
2790: NEW@emph{:postcondition} @emph{name}=$%@emph{^CLASS}(@emph{initializer-list})
2791: @end example
2792:
2793: In its object-oriented form, @code{NEW} creates an instance of class @emph{^CLASS} in local variable @emph{name} and calls the constructor of @emph{^CLASS}, passing @emph{initializer-list} as its argument(s).
2794:
1.1 snw 2795: @node OPEN
2796: @section OPEN
2797: @cindex OPEN
2798: @cindex commands, OPEN
2799:
2800: Opens sequential or socket I/O devices and files and associates them with a numeric FreeM input/output channel.
2801:
2802: @emph{Syntax (Sequential Files)}
2803:
2804: @example
2805: @code{OPEN@emph{:postcondition} @emph{channel}:"@emph{filename}/@emph{access-mode}"}
2806: @end example
2807:
2808: Opens @emph{filename} for reading and/or writing, and associates the file with FreeM I/O channel @emph{channel}, provided that the optional @emph{postcondition} is @emph{true} or omitted.
2809: The below table lists the valid options for @emph{access-mode}:
2810:
2811: @table @code
2812: @item r
2813: Read-only access
2814: @item w
2815: Create a new file for write access
2816: @item a
2817: Write access; append to existing file
2818: @item r+
2819: Read/write access
2820: @end table
2821:
2822: @cartouche
2823: @quotation
2824: @emph{I/O Path}
2825:
2826: You cannot specify a fully-qualified filesystem path in the FreeM @code{OPEN} command. By default, FreeM will assume that @emph{filename} exists in the directory indicated in @code{^$JOB($JOB,"CWD")}. If you wish to
2827: access files in other directories, you must first set the @emph{I/O Path} in @code{^$JOB($JOB,"IOPATH")}.
2828:
2829: The following example will set the I/O path to @code{/etc}:
2830:
2831: @example
2832: @code{SET ^$JOB($JOB,"IOPATH")="/etc"}
2833: @end example
2834:
2835: @end quotation
2836: @end cartouche
2837:
2838: If @emph{channel} was already @code{OPEN}ed in the current process, calling @code{OPEN} on the same channel again implicitly closes the file or device currently associated with @emph{channel}.
2839:
2840: @emph{Syntax (Network Sockets)}
2841:
2842: Network sockets use a dedicated range of FreeM I/O channels ranging from 100-255. @code{OPEN}ing a socket I/O channel does @emph{not} implicitly connect the socket. Connecting the socket to the specified remote host is accomplished by the @code{/CONNECT} control mnemonic supplied to the @code{USE} command.
2843:
2844: @example
2845: OPEN@emph{:postcondition} @emph{socket-channel}:"@emph{hostname-or-address}:@emph{port}:@emph{address-family}:@emph{connection-type}"
2846: @end example
2847:
2848: @emph{Socket Parameters}
2849:
2850: @table @emph
2851:
2852: @item socket-channel
2853: The socket I/O channel to use. This must be in the range of 100-255.
2854:
2855: @item hostname-or-address
2856: The hostname or IP address to connect to. If a hostname is supplied, @code{OPEN} will implictly do a name lookup, the mechanism of which is typically determined by the configuration of @code{/etc/nsswitch.conf} on most UNIX and UNIX-like platforms.
2857:
2858: @item port
2859: The TCP or UDP port to which the socket will connect on the remote host.
2860:
2861: @item address-family
2862: The address family to use. Either @emph{IPV4} or @emph{IPV6}.
2863:
2864: @item connection-type
2865: Which connection type to use. Either @emph{TCP} or @emph{UDP}.
2866:
2867: @end table
2868:
2869: If you do not specify the address family and connection type, they will default to @emph{IPV4} and @emph{TCP}, respectively.
2870:
2871: @node QUIT
2872: @section QUIT
2873: @cindex QUIT
2874: @cindex commands, QUIT
2875:
2876: @code{QUIT} will end execution of the current process level, optionally returning @emph{expr}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2877:
2878: @code{QUIT} with @emph{expr} when an argument is not expected will raise error @code{M16}; @code{QUIT} without @emph{expr} when an argument is expected will raise error @code{M17}.
2879:
2880: Argumentless @code{QUIT} may also be used to exit a @code{FOR} loop occurring on the same line.
2881:
2882: @emph{Syntax}
2883: @example
2884: QUIT[@emph{:postcondition}] [@emph{expr}]
2885: @end example
2886:
2887: @node READ
2888: @section READ
2889: @cindex READ
2890: @cindex commands, READ
2891:
2892: The @code{READ} command takes input from I/O channel @code{$IO} and stores it into specified variables, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2893:
2894: @emph{Syntax}
2895: @example
2896: READ[@emph{:postcondition}] @emph{read-argument}[,...@emph{read-argument}]
2897: @end example
2898:
2899: Each @emph{read-argument} may be one of the following:
2900:
2901: @table @asis
2902:
2903: @item String Literal
2904: String literal @emph{read-argument}s will be output to @code{$IO} unmodified.
2905:
2906: @item Format Specifier
2907: One or more of the following:
2908:
2909: @table @asis
2910: @item @code{!} (newline)
2911: Advances the cursor down by one line and returns it to the first column.
2912:
2913: @item @code{#} (form-feed)
2914: Advances the screen down by @code{$ZROWS} and moves the cursor to the upper-left corner of the screen.
2915:
2916: @item @code{?@emph{n}} (position)
2917: Advances the cursor and @code{$X} forward to position @emph{n}.
2918:
2919: @end table
2920:
2921: @item Single-Character Read (@code{*@emph{variable-name}[@emph{:timeout}]})
2922: Reads one character into variable @emph{variable-name}. If the optional @emph{timeout} is specified, will wait @emph{timeout} seconds to retrieve one character. If a character is read within @emph{timeout} seconds, @code{$TEST} will be set to @emph{1}. If no character is read within @emph{timeout} seconds, @code{$TEST} will be set to @emph{0}.
2923:
2924: @item Variable-Length Character Read (@code{@emph{variable-name}[@emph{:timeout}]})
2925: Reads characters into @emph{variable-name} until the character or character pair in @code{^$DEVICE(@emph{io-channel},"OPTIONS","TERMINATOR")} is encountered. If the optional @emph{timeout} is specified, will wait @emph{timeout} seconds to retrieve characters. If characters are read within @emph{timeout} seconds, @code{$TEST} will be set to @emph{1}. If no character is read within @emph{timeout} seconds, @code{$TEST} will be set to @emph{0}.
2926:
2927: @item Fixed-Length Character Read (@code{@emph{variable-name}#@emph{count}[@emph{:timeout}]})
2928: Reads @emph{count} characters into @emph{variable-name}. If the optional @emph{timeout} is specified, will wait @emph{timeout} seconds to retrieve characters. If characters are read within @emph{timeout} seconds, @code{$TEST} will be set to @emph{1}. If no character is read within @emph{timeout} seconds, @code{$TEST} will be set to @emph{0}.
2929:
2930: @item Control Mnemonic (@code{/@emph{control-mnemonic}[@emph{(arg1[,...argN])}]})
2931: Outputs X3.64 control mnemonic @emph{control-mnemonic} to @code{$IO}. Please see the appendix on X3.64 Control Mnemonics for more information.
2932:
2933: @end table
2934:
2935: @node SET
2936: @section SET
2937: @cindex SET
2938: @cindex commands, SET
2939:
2940: The @code{SET} command places values into one or more variables, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2941:
2942: @emph{Syntax}
2943: @example
2944: SET[@emph{:postcondition}] @emph{set-argument}[=@emph{expression} | @emph{postfix-operator}][@emph{,...set-argument}[=@emph{expression} | @emph{postfix-operator}]]
2945: @end example
2946:
2947: Each @emph{set-argument} can be:
2948:
2949: @table @asis
2950: @item @emph{variable-name}
2951: A local variable, global variable, writable intrinsic special variable, or writable structured system variable.
2952:
2953: @item @emph{lhs-function}
2954: @code{$EXTRACT} or @code{$PIECE}.
2955: @end table
2956:
2957: If any grouping of @emph{set-argument}s is surrounded by parentheses, all @emph{set-argument}s in the parenthesized group will be set to the result of @emph{expression}.
2958:
2959: If @emph{postfix-operator} is used instead of @code{=@emph{expression}}, the results of applying @emph{postfix-operator} to the @emph{set-argument} will be stored in @emph{set-argument}. @emph{postfix-operator} may not be used following a parenthesized group of @emph{set-argument}s.
2960:
2961: @emph{Example (postfix-operator)}
2962:
2963: @example
2964: SET A++,B-- ; increments A, decrements B
2965: @end example
2966:
2967: @node TCOMMIT
2968: @section TCOMMIT
2969: @cindex TCOMMIT
2970: @cindex commands, TCOMMIT
2971:
2972: Commits all pending transactions to the data files, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2973:
2974: @emph{Syntax}
2975: @example
2976: TCOMMIT[@emph{:postcondition}]
2977: @end example
2978:
2979: @node THEN
2980: @section THEN
2981: @cindex THEN
2982: @cindex commands, THEN
2983:
2984: Saves the value of @code{$TEST} until the end of the current line, restoring it at the end of the current line or when a @code{QUIT} is encountered. @code{THEN} should be used in all new code in conjunction with @code{IF}.
2985:
2986: @emph{Example}
2987: @example
2988: IF 1 THEN WRITE "HELLO!",!
2989: @end example
2990:
2991: @node TROLLBACK
2992: @section TROLLBACK
2993: @cindex TROLLBACK
2994: @cindex commands, TROLLBACK
2995:
2996: Rolls back all pending transactions for the current process, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2997:
2998: @emph{Syntax}
2999:
3000: @example
3001: TROLLBACK[@emph{:postcondition}]
3002: @end example
3003:
3004: @node TSTART
3005: @section TSTART
3006: @cindex TSTART
3007: @cindex commands, TSTART
3008:
3009: Introduces a new transaction level, incrementing @code{$TLEVEL}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted. Any global data file operations encountered when @code{$TLEVEL} is greater than zero will not be committed to the global data files until @code{TCOMMIT} is encountered.
3010:
3011: If a transaction is restartable, variables in the @emph{variables-list} will be restored to their original values on a restart of the transaction.
3012:
3013: @emph{Syntax}
3014:
3015: @example
3016: TSTART[@emph{:postcondition}] @emph{<variables-list>}:@emph{<transaction-parameters>}
3017: @end example
3018:
3019: @emph{<variables-list>} can be:
3020:
3021: @table @asis
3022:
3023: @item @code{()}
3024: Do not save off any local variables. Makes the transaction non-restartable.
3025:
3026: @item @code{*}
3027: Save off all local variables. Makes the transaction restartable.
3028:
3029: @item @code{@emph{variableName}}
3030: Saves off only one local variable, @emph{variableName}. Makes the transaction restartable.
3031:
3032: @item @code{(@emph{variableName1},...,@emph{variableNameN})}
3033: Saves off all local variables listed. Makes the transaction restartable.
3034:
3035: @end table
3036:
3037: @emph{<transaction-parameters>} can be:
3038:
3039: @table @asis
3040:
3041: @item @code{S[ERIAL]}
3042: Forces ACID properties on the transaction. When @code{SERIAL} is not selected, transactions occur in batch mode, and no attempt is made to guarantee ACID properties.
3043:
3044: @item @code{T[RANSACTIONID]=@emph{transaction-id}}
3045: Sets the ID of the transaction to @emph{transaction-id}
3046:
3047: @end table
3048:
3049: If you are using more than one transaction parameter, surround all of them in parentheses and separate them with commas, e.g.:
3050:
3051: @example
3052: TSTART (FOO,BAR):(SERIAL,TRANSACTIONID="FOO")
3053: @end example
3054:
3055:
3056: @node USE
3057: @section USE
3058: @cindex USE
3059: @cindex commands, USE
3060:
3061: Sets @code{$IO} to a particular FreeM I/O channel, allowing @code{READ}s from and @code{WRITE}s to the associated terminal, sequential file, or network socket. Also sets various device parameters.
3062:
3063: @emph{Syntax (Terminal)}
3064:
3065: @example
3066: USE@emph{:postcondition} @emph{io-channel}[:(@emph{right-margin}:@emph{input-field-length}:@emph{device-status-word}:@emph{position}:@emph{line-terminator}:@emph{break-key})]
3067: @end example
3068:
3069: For terminals, @emph{io-channel} must be 0.
3070:
3071: Semantic and functional description of each device parameter TBA.
3072:
3073: @emph{Syntax (Sequential Files)}
3074:
3075: @example
3076: USE@emph{:postcondition} @emph{io-channel}[:@emph{seek-position}:@emph{terminator}:@emph{nodelay})]
3077: @end example
3078:
3079: For sequential files, @emph{io-channel} must be in the range 1-99.
3080:
3081: Semantic and functional description of each device parameter TBA.
3082:
3083: @emph{Syntax (Network Sockets)}
3084:
3085: @example
3086: USE@emph{:postcondition} @emph{io-channel}
3087: @end example
3088:
3089: The above syntax will set @code{$IO} to @emph{io-channel}, directing successive @code{READ}s and @code{WRITE}s to @emph{io-channel}, provided the optional @emph{postcondition} is @emph{true} or omitted.
3090:
3091: @example
3092: USE@emph{:postcondition} @emph{io-channel}:/CONNECT
3093: @end example
3094:
3095: The above syntax will set @code{$IO} to @emph{io-channel}, as in the prior example, but will also attempt to connect to the host and port specified for @emph{io-channel} when it was @code{OPEN}ed. The @code{/CONNECT} control mnemonic is only valid for socket channels whose connection type is @code{TCP}. Using @code{/CONNECT} on a @code{UDP} socket channel will throw @code{SCKAERR} (error code 55).
3096:
3097: For network sockets, @emph{io-channel} must be in the range 100-255.
3098:
3099: @node VIEW
3100: @section VIEW
3101: @cindex VIEW
3102: @cindex commands, VIEW
3103:
3104: Provides write access to various FreeM internal parameters, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
3105:
3106: @emph{Syntax}
3107: @example
3108: VIEW[@emph{:postcondition}] @emph{view-number}[:@emph{view-argument}[:@emph{view-argument}...]]
3109: @end example
3110:
3111: The @emph{view-number} argument can be one of the following:
3112:
3113: @table @asis
3114:
3115: @item @code{21} - Close All Globals
3116: Closes all global data files open in the current process. Takes no arguments.
3117:
3118: @emph{Syntax}
3119: @example
3120: VIEW 21
3121: @end example
3122:
3123: @item @code{52} - Set G0 Input Translation Table for @code{$IO}
3124:
3125: @emph{Syntax}
3126: @example
3127: VIEW 52:@emph{expr V trantab}
3128: @end example
3129:
3130: @item @code{53} - Set G0 Output Translation Table for @code{$IO}
3131:
3132: @emph{Syntax}
3133: @example
3134: VIEW 53:@emph{expr V trantab}
3135: @end example
3136:
3137: @item @code{54} - Set G1 Input Translation Table for @code{$IO}
3138:
3139: @emph{Syntax}
3140: @example
3141: VIEW 54:@emph{expr V trantab}
3142: @end example
3143:
3144: @item @code{55} - Set G1 Output Translation Table for @code{$IO}
3145:
3146: @emph{Syntax}
3147: @example
3148: VIEW 55:@emph{expr V trantab}
3149: @end example
3150:
3151: @item @code{62} - Set @code{$RANDOM} Seed Number
3152: Sets the seed number used by @code{$RANDOM} to @emph{numexpr}.
3153:
3154: @emph{Syntax}
3155: @example
3156: VIEW 62:@emph{numexpr}
3157: @end example
3158:
3159: @item @code{63} - Set @code{$RANDOM} Parameter A
3160: Sets the number used for @code{$RANDOM} Parameter A to @emph{numexpr}.
3161:
3162: @emph{Syntax}
3163: @example
3164: VIEW 63:@emph{numexpr}
3165: @end example
3166:
3167: @item @code{64} - Set @code{$RANDOM} Parameter B
3168: Sets the number used for @code{$RANDOM} Parameter B to @emph{numexpr}.
3169:
3170: @emph{Syntax}
3171: @example
3172: VIEW 64:@emph{numexpr}
3173: @end example
3174:
3175: @item @code{65} - Set @code{$RANDOM} Parameter C
3176: Sets the number used for @code{$RANDOM} Parameter C to @emph{numexpr}.
3177:
3178: @emph{Syntax}
3179: @example
3180: VIEW 65:@emph{numexpr}
3181: @end example
3182:
3183: @item @code{66} - Set or Clear @code{SIGTERM} Handling Flag
3184: Enables or disables handling of @code{SIGTERM} UNIX signals. If @emph{tvexpr} evaluates to 1 (@emph{true}), @code{SIGTERM} handling will be enabled. Otherwise, @code{SIGTERM} handling will be disabled.
3185:
3186: @emph{Syntax}
3187: @example
3188: VIEW 66:@emph{tvexpr}
3189: @end example
3190:
3191: @item @code{67} - Set or Clear @code{SIGHUP} Handling Flag
3192: Enables or disables handling of @code{SIGHUP} UNIX signals. If @emph{tvexpr} evaluates to 1 (@emph{true}), @code{SIGHUP} handling will be enabled. Otherwise, @code{SIGHUP} handling will be disabled.
3193:
3194: @emph{Syntax}
3195: @example
3196: VIEW 67:@emph{tvexpr}
3197: @end example
3198:
3199: @item @code{70} - Set @code{$ZSORT}/@code{$ZSYNTAX} Flag
3200: Selects whether @code{$ZS} resolves to @code{$ZSORT} or @code{$ZSYNTAX}.
3201:
3202: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZSYNTAX}. Otherwise, selects @code{$ZSORT}.
3203:
3204: @emph{Syntax}
3205: @example
3206: VIEW 70:@emph{tvexpr}
3207: @end example
3208:
3209: @item @code{71} - Set @code{$ZNEXT}/@code{$ZNAME} Flag
3210: Selects whether @code{$ZN} resolves to @code{$ZNEXT} or @code{$ZNAME}.
3211:
3212: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZNAME}. Otherwise, selects @code{$ZNEXT}.
3213:
3214: @emph{Syntax}
3215: @example
3216: VIEW 71:@emph{tvexpr}
3217: @end example
3218:
3219: @item @code{72} - Set @code{$ZPREVIOUS}/@code{$ZPIECE} Flag
3220: Selects whether @code{$ZP} resolves to @code{$ZPREVIOUS} or @code{$ZPIECE}.
3221:
3222: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZPIECE}. Otherwise, selects @code{$ZPREVIOUS}.
3223:
3224: @emph{Syntax}
3225: @example
3226: VIEW 72:@emph{tvexpr}
3227: @end example
3228:
3229: @item @code{73} - Set @code{$ZDATA}/@code{$ZDATE} Flag
3230: Selects whether @code{$ZD} resolves to @code{$ZDATA} or @code{$ZDATE}.
3231:
3232: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZDATE}. Otherwise, selects @code{$ZDATA}.
3233:
3234: @emph{Syntax}
3235: @example
3236: VIEW 73:@emph{tvexpr}
3237: @end example
3238:
3239: @item @code{79} - Set Old @code{ZJOB} vs. New @code{ZJOB} Flag
3240: If @emph{tvexpr} evaluates to @emph{true}, sets the @code{ZJOB} mode to new, otherwise, sets it to old.
3241:
3242: @emph{Syntax}
3243: @example
3244: VIEW 79:@emph{tvexpr}
3245: @end example
3246:
3247: @item @code{80} - Set or Clear 8-Bit Flag
3248: If @emph{tvexpr} evaluates to @emph{true}, sets FreeM to 8-bit mode. Otherwise, sets FreeM to 7-bit mode.
3249:
3250: @emph{Syntax}
3251: @example
3252: VIEW 80:@emph{tvexpr}
3253: @end example
3254:
3255: @item @code{81} - Set or Clear PF1 Flag
3256: If @emph{tvexpr} evaluates to @emph{true}, sets the @code{PF1} flag. We do not yet know what this does.
3257:
3258: @emph{Syntax}
3259: @example
3260: VIEW 81:@emph{tvexpr}
3261: @end example
3262:
3263: @item @code{83} - Set or Clear Text in @code{$ZERROR} Flag
3264: If @emph{tvexpr} evaluates to @emph{true}, descriptive error messages will be included in @code{$ZERROR}. Otherwise, only the short error code (i.e. @emph{ZILLFUN}) will be included in @code{$ZERROR}.
3265:
3266: @emph{Syntax}
3267: @example
3268: VIEW 83:@emph{tvexpr}
3269: @end example
3270:
3271: @item @code{92} - Set Type Mismatch Error Flag on @code{EUR2DEM}
3272: If @emph{tvexpr} evaluates to @emph{true}, a type mismatch error will be thrown in @code{EUR2DEM} currency conversions in certain situations that we do not yet understand.
3273:
3274: @emph{Syntax}
3275: @example
3276: VIEW 92:@emph{tvexpr}
3277: @end example
3278:
3279: @item @code{93} - Define @code{ZKEY} Production Rule
3280: We do not know what this does.
3281:
3282: @item @code{96} - Set Global Prefix
3283: Forces global data filenames to be prefixed with the result of @emph{expr}.
3284:
3285: @emph{Syntax}
3286: @example
3287: VIEW 96:@emph{expr V string}
3288: @end example
3289:
3290: @item @code{97} - Set Global Postfix
3291: Forces global data filenames to be postfixed with the result of @emph{expr}.
3292:
3293: @emph{Syntax}
3294: @example
3295: VIEW 97:@emph{expr V string}
3296: @end example
3297:
3298: @item @code{98} - Set Routine Extension
3299: Sets the default extension for M routine filenames to the result of @emph{expr}.
3300:
3301: @emph{Syntax}
3302: @example
3303: VIEW 98:@emph{expr V string}
3304: @end example
3305:
3306: @item @code{101} - Set @code{ierr}
3307: Sets the FreeM internal @code{ierr} value to @emph{intexpr}. Used by some FreeM polyfills (commands or functions implemented in M code).
3308:
3309: @emph{Syntax}
3310: @example
3311: VIEW 101:@emph{intexpr}
3312: @end example
3313:
3314: @item @code{102} - Set @code{ierr} (Deferred)
3315: Sets the FreeM internal @code{ierr} value to @emph{intexpr}, but only after the current process stack level is exited. Used by FreeM polyfills to throw an error that will appear to come from the user's own code rather than the polyfill implementation M code.
3316:
3317: @emph{Syntax}
3318: @example
3319: VIEW 102:@emph{intexpr}
3320: @end example
3321:
3322: @item @code{103} - Signal @code{MERGE} to @code{^$WINDOW} Complete
3323: Signals FreeM's MWAPI implementation that a @code{MERGE} to @code{^$WINDOW} or descendant subscripts thereof has completed.
3324:
3325: @emph{Syntax}
3326: @example
3327: VIEW 103[@emph{:subscript}]
3328: @end example
3329:
3330: @item @code{110} - Set Local @code{$ORDER}/@code{$QUERY} Data Value
3331: Sets the local variable @code{$ORDER}/@code{$QUERY} data value to the result of @emph{expr}. We're not entirely sure what this is.
3332:
3333: @emph{Syntax}
3334: @example
3335: VIEW 110:@emph{expr}
3336: @end example
3337:
3338: @item @code{111} - Set Global @code{$ORDER}/@code{$QUERY} Data Value
3339: Sets the global variable @code{$ORDER}/@code{$QUERY} data value to the result of @emph{expr}. We're not entirely sure what this is.
3340:
3341: @emph{Syntax}
3342: @example
3343: VIEW 111:@emph{expr}
3344: @end example
3345:
3346: @item @code{113} - Set @code{termio} Information
3347: We don't know what this does.
3348:
3349: @item @code{133} - Remember @code{ZLOAD} Directory on @code{ZSAVE}
3350: We don't know what this does, but it takes a @emph{tvexpr}.
3351:
3352: @emph{Syntax}
3353: @example
3354: VIEW 133:@emph{tvexpr}
3355: @end example
3356:
3357: @end table
3358:
3359:
3360:
3361: @node WRITE
3362: @section WRITE
3363: @cindex WRITE
3364: @cindex commands, WRITE
3365:
3366: @node XECUTE
3367: @section XECUTE
3368: @cindex XECUTE
3369: @cindex commands, XECUTE
3370:
1.46 snw 3371: @node ZASSERT
3372: @section ZASSERT
3373: @cindex ZASSERT
3374: @cindex commands, ZASSERT
3375: @cindex commands, debugging
3376: @cindex commands, implementation-specific
3377: @cindex commands, non-standard
3378: @emph{FreeM Extension}
3379:
3380: Triggers error @code{ZASSERT} if the supplied truth-valued expression @emph{tvexpr} is @emph{false} (@emph{1} is @emph{true}, and @emph{0} is @emph{false}), and that the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
3381:
3382: The @code{ZASSERT} error is catchable whether using standard-style, FreeM-style, or DSM 2.0-style error processing.
3383:
3384: @emph{Syntax}
3385:
3386: @example
3387: ZASSERT@emph{:postcondition} @emph{<tvexpr>}
3388: @end example
3389:
3390: @emph{Example}
3391:
3392: @example
3393: DEFAULT.USER> SET DEBUG=1
3394:
3395:
3396: DEFAULT.USER> ZASSERT:DEBUG 1=1
3397:
3398:
3399: DEFAULT.USER> ZASSERT:DEBUG 1=0
3400:
3401:
3402: >> Error ZASSERT: programmer assertion failed in SYSTEM::^%SYSINIT [$STACK = 0]
3403: >> ZASSERT:DEBUG 1=0
3404: ^
3405: @end example
3406:
1.1 snw 3407: @node ZBREAK
3408: @section ZBREAK
3409: @cindex ZBREAK
3410: @cindex commands, ZBREAK
3411: @cindex commands, debugging
3412: @cindex commands, implementation-specific
3413: @cindex commands, non-standard
3414: @emph{FreeM Extension}
3415:
1.48 snw 3416: Sets or clears the @code{ZBREAK} flag@footnote{NOTE: FreeM team needs to investigate how @code{zbreakon} and @code{zbflag} affect program execution.}, based on the result of evaluating @emph{tvexpr}.
3417:
3418: @emph{Syntax}
3419:
3420: @example
3421: ZBREAK @emph{tvexpr}
3422: @end example
3423:
1.42 snw 3424: @node ZCONST
3425: @section ZCONST
3426: @cindex ZCONST
3427: @cindex commands, ZCONST
3428: @cindex commands, non-standard
3429: @emph{FreeM Extension}
3430:
3431: Defines a local @emph{constant}, or variable that cannot be altered after its initial definition, provided the optional @emph{postcondition} is @emph{true} or omitted.
3432:
3433: Constants must only be locals, and globals are not supported.
3434:
3435: @emph{Syntax}
3436:
3437: @example
3438: @code{ZCONST@emph{:postcondition} @emph{mref1}=@emph{initial-value1},...,@emph{mrefN}=@emph{initial-valueN}}
3439: @end example
3440:
1.48 snw 3441: @node ZGOTO
3442: @section ZGOTO
3443: @cindex ZGOTO
3444: @cindex commands, ZGOTO
1.1 snw 3445: @cindex commands, implementation-specific
3446: @cindex commands, non-standard
3447: @emph{FreeM Extension}
3448:
1.48 snw 3449: In its argumented form, enables @code{BREAK} mode and branches unconditionally to @emph{entryref}.
3450:
3451: @emph{Syntax}
3452:
3453: @example
3454: ZGOTO @emph{entryref}
3455: @end example
3456:
3457: In its argumented form, resumes execution after a @code{BREAK}.
3458:
3459: @emph{Syntax}
3460:
3461: @example
3462: ZGOTO
3463: @end example
3464:
1.1 snw 3465: @node ZHALT
3466: @section ZHALT
3467: @cindex ZHALT
3468: @cindex commands, ZHALT
3469: @cindex commands, implementation-specific
3470: @cindex commands, non-standard
3471: @emph{FreeM Extension}
3472:
1.48 snw 3473: In its single-argumented form, @code{ZHALT} command is used to exit the FreeM process with a specific return value @emph{intexpr}.
3474:
3475: @emph{Syntax}
3476:
3477: @example
3478: ZHALT @emph{intexpr}
3479: @end example
3480:
3481: In its argumentless form, @code{ZHALT} is synonymous with @code{HALT}.
3482:
3483: @emph{Syntax}
3484:
3485: @example
3486: ZHALT
3487: @end example
3488:
1.1 snw 3489: @node ZINSERT
3490: @section ZINSERT
3491: @cindex ZINSERT
3492: @cindex commands, ZINSERT
3493: @cindex commands, implementation-specific
3494: @cindex commands, non-standard
3495: @emph{FreeM Extension}
3496:
3497: @node ZJOB
3498: @section ZJOB
3499: @cindex ZJOB
3500: @cindex commands, ZJOB
3501: @cindex commands, implementation-specific
3502: @cindex commands, non-standard
3503: @emph{FreeM Extension}
3504:
3505: When @code{ZJOB} is used, the semantics are identical to @code{JOB}, with the exception that the @emph{timeout} is forced to be @code{0}, regardless of what the user specifies.
3506:
3507: For more information, see @code{JOB}.
3508:
3509: @node ZLOAD
3510: @section ZLOAD
3511: @cindex ZLOAD
3512: @cindex commands, ZLOAD
3513: @cindex commands, implementation-specific
3514: @cindex commands, non-standard
3515: @emph{FreeM Extension}
3516:
3517: Loads routine @emph{<routine-name>} into FreeM's routine buffer, provided the optional @emph{postcondition} is @emph{true} or omitted.
3518:
3519: @emph{Syntax}
3520:
3521: @example
3522: ZLOAD@emph{:postcondition} @emph{<routine-name>}
3523: @end example
3524:
1.42 snw 3525:
3526: @node ZMAP
3527: @section ZMAP
3528: @cindex ZMAP
3529: @cindex commands, ZMAP
3530: @cindex commands, implementation-specific
3531: @cindex commands, non-standard
3532:
3533: Maps global name @code{gvn} to be mapped to the non-default namespace @emph{expr V namespace}, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
3534:
3535: @emph{Syntax}
3536:
3537: @example
3538: ZMAP[@emph{:postcondition}] GLOBAL @emph{gvn}=@emph{expr V namespace}
3539: @end example
3540:
1.1 snw 3541: @node ZNEW
3542: @section ZNEW
3543: @cindex ZNEW
3544: @cindex commands, ZNEW
3545: @cindex commands, implementation-specific
3546: @cindex commands, non-standard
3547: @emph{FreeM Extension}
3548:
3549: @node ZPRINT
3550: @section ZPRINT
3551: @cindex ZPRINT
3552: @cindex commands, ZPRINT
3553: @cindex commands, implementation-specific
3554: @cindex commands, non-standard
3555: @emph{FreeM Extension}
3556:
3557: Prints the contents of the current routine buffer, provided the optional @emph{postcondition} is @emph{true} or omitted.
3558:
3559: @emph{Syntax}
3560:
3561: @example
3562: ZPRINT@emph{:postcondition}
3563: @end example
3564:
3565: @node ZQUIT
3566: @section ZQUIT
3567: @cindex ZQUIT
3568: @cindex commands, ZQUIT
3569: @cindex commands, implementation-specific
3570: @cindex commands, non-standard
3571: @emph{FreeM Extension}
3572:
3573: In its single-argument form, quits from @emph{levels} levels of the stack, provided the optional @emph{postcondition} is @emph{true} or omitted.
3574:
3575: In its argumentless form, quits from @code{$STACK} levels of the stack, provided the optional @emph{postcondition} is @emph{true} or omitted.
3576:
3577: @emph{Syntax}
3578:
3579: @example
3580: @code{ZQUIT@emph{:postcondition} [@emph{levels}]}
3581: @end example
3582:
3583: @node ZREMOVE
3584: @section ZREMOVE
3585: @cindex ZREMOVE
3586: @cindex commands, ZREMOVE
3587: @cindex commands, implementation-specific
3588: @cindex commands, non-standard
3589: @emph{FreeM Extension}
3590:
3591: @node ZSAVE
3592: @section ZSAVE
3593: @cindex ZSAVE
3594: @cindex commands, ZSAVE
3595: @cindex commands, implementation-specific
3596: @cindex commands, non-standard
3597: @emph{FreeM Extension}
3598:
1.42 snw 3599:
3600: @node ZTHROW
3601: @section ZTHROW
3602: @cindex ZTHROW
3603: @cindex commands, ZTHROW
3604: @cindex commands, non-standard
3605: @emph{FreeM Extension}
3606:
3607: Raises an error condition as long as the optional @emph{postcondition} is @emph{true} or omitted.
3608:
3609: @emph{Syntax}
3610:
3611: @example
3612: @code{ZTHROW@emph{:postcondition} @emph{expr V error-code}}
3613: @end example
3614:
3615: @emph{Example}
3616:
3617: @example
3618: @code{ZTHROW "M102"}
3619: @end example
3620:
1.1 snw 3621: @node ZTRAP
3622: @section ZTRAP
3623: @cindex ZTRAP
3624: @cindex commands, ZTRAP
3625: @cindex commands, debugging
3626: @cindex commands, implementation-specific
3627: @cindex commands, non-standard
3628: @emph{FreeM Extension}
3629:
1.50 snw 3630: Synonymous with @ref{ZTHROW}.
3631:
1.42 snw 3632: @node ZUNMAP
3633: @section ZUNMAP
3634: @cindex ZUNMAP
3635: @cindex commands, ZUNMAP
3636: @cindex commands, implementation-specific
3637: @cindex commands, non-standard
3638:
3639: Removes any mapping connecting @emph{gvn} to a non-default namespace, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
3640:
3641: @emph{Syntax}
3642:
3643: @example
3644: ZUNMAP GLOBAL @emph{gvn}
3645: @end example
3646:
3647: @node ZWATCH
3648: @section ZWATCH
3649: @cindex ZWATCH
3650: @cindex commands, ZWATCH
3651: @cindex commands, debugging
3652: @cindex commands, implementation-specific
3653: @cindex commands, non-standard
3654: @emph{FreeM Extension}
3655:
3656: Sets a watchpoint on a global, local, or SSVN node.
3657:
3658: @emph{Syntax}
3659:
3660:
3661: In its @emph{argumentless} form, @code{ZWATCH} toggles watchpoints on and off, provided the optional @emph{postcondition} is @emph{true} or omitted.
3662:
3663: @example
3664: ZWATCH[@emph{:postcondition}]
3665: @end example
3666:
3667: In its @emph{inclusive} form, @code{ZWATCH} adds, removes, or examines watchpoints, provided the optional @emph{postcondition} is @emph{true} or omitted.
3668:
3669: A @code{+} adds a new watchpoint to the following variable.
3670:
3671: A @code{-} removes an existing watchpoint for the following variable.
3672:
3673: A @code{?} examines the status of a watchpoint for the following variable.
3674:
3675: @example
3676: ZWATCH[@emph{:postcondition}] [+|-|?]@emph{var1}...,[+|-|?]@emph{varN}
3677: @end example
3678:
3679:
3680: The following example demonstrates turning watchpoint processing on and adding a watchpoint for global variable @code{^snw(1)}. It then changes the value of @code{^snw(1)}.
3681:
3682: @example
3683: DEFAULT.USER> ZWATCH
3684:
3685: Watchpoints enabled.
3686:
3687: DEFAULT.USER> ZWATCH +^SNW(1)
3688:
3689: Added '^SNW("1")' to the watchlist.
3690:
3691: DEFAULT.USER> SET ^SNW(1)="new value"
3692:
3693: >> WATCHPOINT: ^SNW("1") => 'new value' (changed 1 times)
3694:
3695: @end example
3696:
3697: The following example will remove that watchpoint:
3698:
3699: @example
3700: DEFAULT.USER> ZWATCH -^SNW(1)
3701:
3702: Removed '^SNW("1")' from the watchlist.
3703:
3704: DEFAULT.USER> ZWATCH ?^SNW(1)
3705:
3706: '^SNW("1")' is not being watched.
3707: @end example
3708:
3709: @node ZWITH
3710: @section ZWITH
3711: @cindex ZWITH
3712: @cindex commands, ZWITH
3713: @cindex commands, non-standard
3714: @emph{FreeM Extension}
3715:
3716: NOTE: This command may be deprecated and removed in future FreeM releases.
3717:
3718: Sets a prefix to be applied to all subsequent local variable or constant references.
3719:
3720: @emph{Syntax}
3721:
3722: @example
3723: @code{ZWITH@emph{:postcondition} @emph{var-prefix}}
3724: @end example
3725:
3726: In the above single-argument form, sets the @code{$WITH} prefix to @emph{var-prefix}, provided that the optional @emph{postcondition} is either @emph{true} or omitted.
3727:
3728: The @emph{var-prefix} argument may be a string literal or any valid FreeM expression.
3729:
3730: @example
3731: @code{ZWITH@emph{:postcondition}}
3732: @end example
3733:
3734: In the above argumentless form, clears the @code{$WITH} prefix, provided the optional @emph{postcondition} is either @emph{true} or omitted. Equivalent to @code{ZWITH ""}.
3735:
3736:
3737:
3738:
3739:
3740:
3741:
3742:
1.1 snw 3743: @node ZWRITE
3744: @section ZWRITE
3745: @cindex ZWRITE
3746: @cindex commands, ZWRITE
3747: @cindex commands, implementation-specific
3748: @cindex commands, non-standard
3749: @emph{FreeM Extension}
3750:
3751: Writes the names and values of M variables to @code{$IO}.
3752:
3753: @emph{Syntax}
3754:
3755: @example
3756: ZWRITE@emph{:postcondition}
3757: @end example
3758:
3759: In the argumentless form, writes the names and values of all local variables to @code{$IO} if the optional @emph{postcondition} is @emph{true} or omitted.
3760:
3761: @example
3762: ZWRITE@emph{:postcondition} @emph{ArrayName},@dots{}
3763: @end example
3764:
3765: In the inclusive form, writes the names and values of all local, global, or structured system variables specified in the list of @emph{ArrayName}s to @code{$IO} if the optional @emph{postcondition} is @emph{true} or omitted.
3766:
3767: @example
3768: ZWRITE@emph{:postcondition} (@emph{ArrayName},@dots{})
3769: @end example
3770:
3771: In the exclusive form, writes all local variables @emph{except} those specified in the list of @emph{ArrayName}s to @code{$IO} if the optional @emph{postcondition} is @emph{true} or omitted.
3772:
3773:
3774: @node Structured System Variables
3775: @chapter Structured System Variables
3776: @cindex variables, structured system
3777: @cindex structured system variables
3778: @cindex SSVNs
3779:
3780: @menu
3781: * ^$CHARACTER:: Character set information.
3782: * ^$DEVICE:: Device information.
3783: * ^$DISPLAY:: Information about graphic display.
3784: * ^$EVENT:: Information supplied about a synchronous or asynchronous event.
3785: * ^$GLOBAL:: Information about M globals.
3786: * ^$JOB:: Information about and control of FreeM jobs.
3787: * ^$LOCK:: Information about the FreeM lock table.
3788: * ^$OBJECT:: Information about FreeM objects.
3789: * ^$ROUTINE:: Information about FreeM routines.
3790: * ^$SYSTEM:: Information about the running system.
3791: * ^$WINDOW:: Configuration of MWAPI windows.
3792: * ^$ZPROCESS:: Information about and control of system processes.
3793: * ^$ZRPI:: Information about and control of Raspberry Pi GPIO pins.
3794: @end menu
3795:
3796: SSVN subscripts are each described in the following format:
3797:
3798: @table @asis
3799: @item @code{@emph{<ssvn-subscript-name>}} +/-R +/-U +/-D
3800: @end table
3801:
3802: The R, U, and D flags represent Read, Update, and Delete. A minus sign indicates that the given operation is @emph{not} allowed, and a plus sign indicates that the given operation @emph{is} allowed.
3803:
3804: @node ^$CHARACTER
3805: @section ^$CHARACTER
3806: @cindex ^$CHARACTER
3807: @cindex structured system variables, ^$CHARACTER
3808:
3809: Exposes character set information. As FreeM currently only supports the @code{M} character set, the first subscript of @code{^$CHARACTER} must always be @code{"M"}.
3810:
3811: The following values for the second subscript are supported:
3812:
3813: @table @asis
3814:
3815: @item @code{IDENT} +R -U -D
3816: Returns the empty string.
3817:
3818: @item @code{COLLATE} +R -U -D
3819: Returns the empty string.
3820:
3821: @item @code{INPUT} +R -U -D
3822: Returns the empty string if the third subscript is @code{M}, otherwise, raises error @code{M38}.
3823:
3824: @item @code{OUTPUT} +R -U -D
3825: Returns the empty string if the third subscript is @code{M}, otherwise, raises error @code{M38}.
3826:
3827: @end table
3828:
3829: @node ^$DEVICE
3830: @section ^$DEVICE
3831: @cindex ^$DEVICE
3832: @cindex structured system variables, ^$DEVICE
3833:
3834: FreeM implements several important pieces of functionality in the @code{^$DEVICE} SSVN.
3835:
3836: The first subscript of @code{^$DEVICE} represents the I/O channel of an @code{OPEN}ed device.
3837:
3838: The following values for the second subscript are supported:
3839:
3840: @table @asis
3841:
3842: @item @code{$DEVICE}
3843: Returns the value of @code{$DEVICE} for the specified I/O channel.
3844:
3845: @item @code{$X} +R -U -D
3846: Returns the horizontal cursor position of a terminal device. Only valid if the I/O channel is @code{0}.
3847:
3848: @item @code{$Y} +R -U -D
3849: Returns the vertical cursor position of a terminal device. Only valid if the I/O channel is @code{0}.
3850:
3851: @item @code{ROWS} +R -U -D
3852: Returns the number of character rows on the terminal device. Only valid if the I/O channel is @code{0}.
3853:
3854: @item @code{COLUMNS} +R -U -D
3855: Returns the number of character columns on the terminal device. Only valid if the I/O channel is @code{0}.
3856:
3857: @item @code{CHARACTER} +R -U -D
3858: Returns the character set of the specified I/O channel; always @code{M} in the current implementation.
3859:
3860: @item @code{INPUT_BUFFER} +R +U -D
3861: Returns or sets the contents of the input buffer for the specified I/O channel. Data populated in this node will remain in the buffer until subsequent @code{READ} command(s) remove it. This can be used to perform input buffer stuffing, i.e., to fill out an interactive form programmatically.
3862:
3863: @item @code{NAME} +R -U -D
3864: Returns the operating system's name for the file, device, or socket attached to the specified I/O channel.
3865:
3866: @item @code{FD} +R -U -D
3867: Returns the UNIX file descriptor of the specified I/O channel.
3868:
3869: @item @code{MODE} +R -U -D
3870: Returns one of @code{READ}, @code{WRITE}, @code{READWRITE}, or @code{APPEND}, depending on the mode in which the specified I/O channel was opened.
3871:
3872: @item @code{EOF} +R -U -D
3873: Returns @code{1} if the I/O channel has encountered an end-of-file condition; @code{0} otherwise. Only valid if the I/O channel is connected to a sequential file.
3874:
3875: @item @code{LENGTH} +R -U -D
3876: Returns the length of the file connected to the I/O channel. Only valid if the I/O channel is connected to a sequential file.
3877:
3878: @item @code{NAMESPACE} +R -U -D
3879: Returns the current @emph{mnemonic-space} in use for the referenced I/O channel. Always @code{X364} for terminals and blank for sequential files.
3880:
3881: @item @code{TYPE} +R -U -D
3882: Returns either @code{1,FILE}, @code{2,SOCKET}, or @code{4,TERMINAL}, depending on the device type associated with the specified I/O channel.
3883:
3884: @item @code{OPTIONS} -R -U -D
3885: The following subscripts reside beneath @code{^$DEVICE(<io-channel>,"OPTIONS")}, and this subscript may not be accessed without one of the following third-level subscripts being specified:
3886:
3887: @table @asis
3888:
3889: @item @code{DSW} +R +U -D
3890: Sets or returns the current @emph{Device Status Word} controlling terminal characteristics. Only valid for I/O channel 0.
3891:
3892: @item @code{TERMINATOR} +R +U -D
3893: Sets or returns the @code{READ} terminator for the specified I/O channel. Must be either @code{$C(13,10)} or @code{$C(10)}. Currently only supported for socket devices (those having an I/O channel of 100-255).
3894:
3895: @item @code{TERMID} +R -U -D
3896: Returns the type of terminal connected to channel 0. Only valid for I/O channel 0.
3897:
3898: @item @code{ECHO} +R +U -D
3899: Enables or disables local echo of characters typed in a @code{READ} command. Only valid for I/O channel 0. Corresponds to bit 0 of the Device Status Word.
3900:
3901: @item @code{DELMODE} +R +U -D
3902: Enables or disables visual backspace during a @code{READ} command. Only valid for I/O channel 0. Corresponds to bit 2 of the Device Status Word.
3903:
3904: @item @code{ESCAPE} +R +U -D
3905: Enables or disables escape sequence processing during a @code{READ} command. Only valid for I/O channel 0. Corresponds to bit 6 of the Device Status Word.
3906:
3907: @item @code{CONVUPPER} +R +U -D
3908: Enables or disables automatic conversion to uppercase of alphabetical characters during a @code{READ} command. Only valid for I/O channel 0. Corresponds to bit 14 of the Device Status Word.
3909:
3910: @item @code{DELEMPTY} +R +U -D
3911: Enables or disables the automatic deletion of empty strings supplied to a @code{READ} command. Only valid for I/O channel 0. Corresponds to bit 19 of the Device Status Word.
3912:
3913: @item @code{NOCTRLS} +R +U -D
3914: TBD. Only valid for I/O channel 0. Corresponds to bit 20 of the Device Status Word.
3915:
3916: @item @code{CTRLOPROC} +R +U -D
3917: Enables or disables @emph{Ctrl-O} processing during @code{READ} commands. Only valid for I/O channel 0. Corresponds to bit 21 of the Device Status Word.
3918:
3919: @item @code{NOTYPEAHEAD} +R +U -D
3920: Enables or disables typeahead buffering during @code{READ} commands. Only valid for I/O channel 0. Corresponds to bit 25 of the Device Status Word.
3921: @end table
3922: @end table
3923:
3924: @emph{Example}
3925:
3926: The following example M code opens @code{/etc/freem.conf} and reads its contents line-by-line until the end of the file is reached.
3927:
3928: @example
3929: SET ^$JOB($JOB,"IOPATH")="/etc" ; set I/O path to /etc
3930: OPEN 1:"freem.conf/r" ; open freem.conf for reading
3931: ;
3932: ; read until we run out of lines
3933: ;
3934: FOR USE 1 READ LINE USE 0 QUIT:^$DEVICE(1,"EOF") D
3935: . WRITE LINE,!
3936: ;
3937: CLOSE 1
3938: QUIT
3939: @end example
3940:
3941: @node ^$DISPLAY
3942: @section ^$DISPLAY
3943: @cindex ^$DISPLAY
3944: @cindex structured system variables, ^$DISPLAY
3945:
3946: Provides information about the specified graphical display. The first subscript corresponds to a display number, which is an integer value, often corresponding to the current value of the @code{$PDISPLAY} ISV.
3947:
3948: The following second-level subscripts and specified descendant subscripts are supported:
3949:
3950: @table @asis
3951:
3952: @item @code{CLIPBOARD} +R +U +D
3953: Retrieves, sets, or erases the contents of the system clipboard.
3954:
3955: @item @code{PLATFORM} +R -U -D
3956: Retrieves the name and version of the underlying window system platform.
3957:
3958: @item @code{SIZE} +R -U -D
3959: Retrieves the display resolution of the specified graphical display. For instance, a 1080p display would have a @code{SIZE} value of @code{1920,1080}.
3960:
3961: @item @code{SPECTRUM} +R -U -D
3962: Retrieves the color depth (number of colors supported) of the specified graphical display.
3963:
3964: @item @code{COLORTYPE} +R -U -D
3965: Always returns @code{COLOR}, as monochrome and grayscale displays are not yet supported in FreeM.
3966:
3967: @item @code{UNITS} +R -U -D
3968: Returns the measurement unit of the specified display, i.e., @code{PIXEL}.
3969:
3970: @item @code{TYPEFACE} +R -U -D
3971: The third-level subscripts beneath this subscript represent a list of font families available on this display. The fourth level subscript is a list of sizes supported for the specified typeface, or @code{0} for vector typefaces, such as TrueType, OpenType, and Adobe Type 1 fonts.
3972:
3973: @end table
3974:
3975: @node ^$EVENT
3976: @section ^$EVENT
3977: @cindex ^$EVENT
3978: @cindex structured system variables, ^$EVENT
3979:
3980: The @code{^$EVENT} SSVN is not yet implemented.
3981:
3982: @node ^$GLOBAL
3983: @section ^$GLOBAL
3984: @cindex ^$GLOBAL
3985: @cindex structured system variables, ^$GLOBAL
3986:
3987: The @code{^$GLOBAL} structured system variable provides information about M globals. The first-level subscript is a global name, sans the leading caret symbol.
3988:
3989: The following second-level subscripts are supported:
3990:
3991: @table @asis
3992:
3993: @item @code{BYTES} +R -U -D
3994: Returns the number of bytes this global occupies in fixed storage.
3995:
3996: @item @code{BLOCKS} +R -U -D
3997: Returns the number of blocks contained in this global.
3998:
3999: @item @code{BLOCKSIZE} +R -U -D
4000: Returns the size of data blocks for this global. Currently, FreeM only supports 1024-byte blocks.
4001:
4002: @item @code{FILE} +R -U -D
4003: Returns the full filesystem path to the data file where this global resides in fixed storage.
4004:
4005: @item @code{NAMESPACE} +R +U +D
4006: Returns or sets the name of the FreeM namespace to which this global belongs. @code{SET}ting this node creates a mapping for the specified global name to a non-default namespace. @code{KILL}ing this node restores the mapping configuration for the specified global to the default.
4007:
4008: @end table
4009:
4010: @node ^$JOB
4011: @section ^$JOB
4012: @cindex ^$JOB
4013: @cindex structured system variables, ^$JOB
4014:
4015: FreeM fully implements @code{^$JOB} per ANSI X11.1-1995, as well as several extensions proposed in the M Millennium Draft Standard.
4016:
4017: The first subscript of @code{^$JOB} represents the @code{$JOB} of the process.
4018:
4019: If you @code{KILL} a first-level subscript of @code{^$JOB}, the @code{SIGTERM} signal will be sent to the corresponding UNIX process, causing pending transactions to be rolled back and the process to be terminated. If the targeted process is in direct mode, the user will be prompted with options of either rolling back or committing any pending transactions.
4020:
4021: The following subscripts are supported:
4022:
4023: @table @asis
4024:
4025: @item @code{GVNDEFAULT} +R +U +D
4026: Contains a default expression to be evaluated if a global variable access attempt results in an @code{M7} error.
4027:
4028: Equivalent to wrapping all global accesses in @code{$GET(@emph{global-name},@emph{string-expr})}.
4029:
4030: @item @code{LVNDEFAULT} +R +U +D
4031: Contains a default expression to be evaluated if a local variable access attempt results in an @code{M6} error.
4032:
4033: Equivalent to wrapping all local accesses in @code{$GET(@emph{global-name},@emph{string-expr})}.
4034:
4035: @item @code{LVNQOVAL} +R +U +D
4036: Contains the data value (if any) at the subscripted local variable reference from the most recent @code{$ORDER} or @code{$QUERY} operation.
4037:
4038: This node is useful for code that uses @code{$ORDER} or @code{$QUERY} heavily in loops that retrieve successive data values, as it will prevent an additional symbol table scan that would result from retrieving the data value in the usual way, thus improving application performance. However, this optimization comes at the cost of compatibility with other M implementations.
4039:
4040: @item @code{GVNQOVAL} +R +U +D
4041: Contains the data value (if any) at the subscripted global variable reference from the most recent @code{$ORDER} or @code{$QUERY} operation.
4042:
4043: This node is useful for code that uses @code{$ORDER} or @code{$QUERY} heavily in loops that retrieve successive data values, as it will prevent an additional data file scan that would result from retrieving the data value in the usual way, thus improving application performance. However, this optimization comes at the cost of compatibility with other M implementations.
4044:
4045: @item @code{ZCOMMANDS} +R +U -D
4046: Contains a space-delimited list of @code{Z}-commands to be treated as intrinsic. Any @code{Z}-command not appearing in this list will be treated as a user-defined command.
4047:
4048: For instance, if command @code{ZFOO} does @emph{not} appear in this list, FreeM will attempt to run @code{^%ZFOO} as a subroutine when the @code{ZFOO} command is encountered in program code.
4049:
4050: If you remove a command from this list, you may provide your own private M implementation of the command in the manner described above.
4051:
4052: If an argument is passed to a @code{Z}-command you implement in M, it is made available to your M code in a variable whose name is specified in @code{^$JOB($JOB,"ZCOMMAND_ARGUMENT_NAME")}, which defaults to @code{%}.
4053:
4054: @item @code{PIPE_GLVN} +R +U -D
4055: Contains an M local or global variable to be used as standard input or standard output for the external shell commands run by @code{!<} and @code{!>}.
4056:
4057: @item @code{ZCOMMAND_ARGUMENT_NAME} +R +U -D
4058: Returns or sets the variable name in which arguments to user-defined @code{Z}-commands are passed. Defaults to @code{%}.
4059:
4060: @item @code{ZFUNCTIONS} +R +U -D
4061: Contains a space-delimited list of @code{Z} functions to be treated as intrinsic. Any @code{Z} function not appearing in this list will be treated as a user-defined extrinsic function.
4062:
4063: For instance, if function @code{$ZFOO} does @emph{not} appear in this list, FreeM will attempt to return the value of @code{$$^%ZFOO} called as an extrinsic function.
4064:
4065: If you remove a function from this list, you may provide your own private M implementation of the function in the manner described above.
4066:
4067: @item @code{ZSVS} +R +U -D
4068: Contains a space-delimited list of @code{Z} special variables to be treated as intrinsic. Any @code{Z} special variable not appearing in this list will be treated as a user-defined extrinsic function taking no arguments.
4069:
4070: For instance, if the special variable @code{$ZFOO} does @emph{not} appear in this list, FreeM will attempt to return the value of @code{$$^%ZFOO} called as an extrinsic function.
4071:
4072: If you remove a built-in special variable from this list, you may provide your own private M implementation of the special variable in the manner described above.
4073:
4074: @item @code{BREAK_HANDLER} +R +U -D
4075: Contains M code to be executed when the @code{BREAK} command is run.
4076:
4077: @item @code{ROUTINE_BUFFER_SIZE} +R +U -D
4078: Returns or sets the number of bytes allocated to each routine buffer. If @code{ROUTINE_BUFFER_AUTO_ADJUST} is set to @code{0}, this determines the maximum size of routines that FreeM will execute.
4079:
4080: @item @code{ROUTINE_BUFFER_COUNT} +R +U -D
4081: Returns or sets the number of routine buffers that FreeM will store in memory concurrently. Raising this value will increase memory usage, but will also increase performance if your applications call many different routines repeatedly.
4082:
4083: @item @code{ROUTINE_BUFFER_AUTO_ADJUST} +R +U -D
4084: Determines whether or not the size of routine buffers will be automatically adjusted at runtime. If set to @code{0}, routine buffers will be fixed to the byte size specified in @code{ROUTINE_BUFFER_SIZE} and may be manually resized using @code{ROUTINE_BUFFER_SIZE}. If set to @code{1}, routine buffers will grow automatically as necessary.
4085:
4086: @item @code{SYMBOL_TABLE_SIZE} +R +U -D
4087: Returns or sets the number of bytes allocated to each of the two FreeM symbol tables. If @code{SYMBOL_TABLE_AUTO_ADJUST} is @code{1}, this value is treated as a default, initial size. If @code{SYMBOL_TABLE_AUTO_ADJUST} is @code{0}, this value controls the fixed size of the two symbol tables.
4088:
4089: @item @code{SYMBOL_TABLE_AUTO_ADJUST} +R +U -D
4090: Determines whether or not the size of the two FreeM symbol tables will be automatically adjusted at runtime. If set to @code{0}, the symbol table will be fixed to the byte size specified in @code{SYMBOL_TABLE_SIZE} and may be manually resized by modifying @code{SYMBOL_TABLE_SIZE}. If set to @code{1}, the two symbol tables will grow automatically as necessary.
4091:
4092:
4093: @item @code{USER_DEFINED_ISV_TABLE_SIZE} +R +U -D
4094: Returns or sets the number of bytes allocated to the FreeM user-defined intrinsic special variable table. If @code{USER_DEFINED_ISV_TABLE_AUTO_ADJUST} is @code{1}, this value is treated as a default, initial size. If @code{USER_DEFINED_ISV_TABLE_AUTO_ADJUST} is @code{0}, this value controls the fixed byte size of the user-defined intrinsic special variable table.
4095:
4096: @item @code{USER_DEFINED_ISV_TABLE_AUTO_ADJUST} +R +U -D
4097: Determines whether or not the size of the FreeM user-defined intrinsic special variable table will be automatically adjusted at runtime. If set to @code{0}, the user-defined ISV table will be fixed to the byte size specified in @code{USER_DEFINED_ISV_TABLE_SIZE} and may be manually resized by modifying @code{USER_DEFINED_ISV_TABLE_SIZE}. If set to @code{1}, the user-defined ISV table will grow automatically as necessary.
4098:
4099: @item @code{GVN_UNIQUE_CHARS} +R +U -D
4100: Returns or sets the number of characters of a global name that make it unique, from 1 to 255.
4101:
4102: @item @code{GVN_CASE_SENSITIVE} +R +U -D
4103: Returns or sets the case sensitivity of global names. If set to @code{0}, global names are case-insensitive. If set to @code{1}, global names are case-sensitive.
4104:
4105: @item @code{GVN_NAME_SUB_LENGTH} +R +U -D
4106: Returns or sets the maximum number of characters of a global name plus all of its subscripts, from 1-255.
4107:
4108: @item @code{GVN_SUB_LENGTH} +R +U -D
4109: Returns or sets the maximum number of characters of a single global subscript, from 1-255.
4110:
4111: @item @code{SINGLE_USER} +R +U -D
1.27 snw 4112: If set to @code{1}, FreeM will skip all file locking operations on globals. If set to @code{0}, FreeM will enforce file locking on both.
1.1 snw 4113:
1.27 snw 4114: Setting @code{SINGLE_USER} to @code{1} will improve FreeM performance, but you must @emph{ONLY} use this on systems where you are absolutely sure that only one FreeM process will run at any given time, as running multiple instances of FreeM concurrently when any of them are set to @code{SINGLE_USER} mode @emph{will} cause global data corruption.
1.1 snw 4115:
4116: @item @code{CHARACTER} +R -U -D
4117: Returns the character set of the job.
4118:
4119: @item @code{CWD} +R +U -D
4120: Returns or sets the current working directory of the job.
4121:
4122: @item @code{OPEN} +R -U -D
4123: The @code{^$JOB($JOB,"OPEN",<channel>} subscripts list the open I/O channels in the specified job.
4124:
4125: @item @code{BERKELEYDB,FLUSH_THRESHOLD} +R +U -D
4126: Returns or sets the number of write operations that will be cached in the BerkeleyDB global handler prior to flushing BerkeleyDB's cache to disk.
4127:
4128: @item @code{EVENT} +R +U +D
4129: The subtree contained under @code{^$JOB($J,"EVENT")} defines asynchronous event handlers for the current job. Please see @emph{Asynchronous Event Handling} for more information.
4130:
4131: @item @code{GLOBAL} +R -U -D
4132: Returns the global environment of the job.
4133:
4134: @item @code{IOPATH} +R +U -D
4135: Returns or sets the @emph{I/O path} to be used by the @code{OPEN} command.
4136:
4137: @item @code{PRIORITY} +R +U -D
4138: Returns or sets the @emph{nice} value of the FreeM job.
4139:
4140: @item @code{REVSTR} +R +U -D
4141: When set to 1, allows @code{$EXTRACT} to accept negative values.
4142:
4143: @item @code{ROUTINE} +R -U -D
4144: Returns the name of the routine currently being executed by the job.
4145:
4146: @item @code{SYMTAB} +R +U -D
4147: Returns or sets the current local variable symbol table in use.
4148:
4149: FreeM supports two unique and independent symbol tables, allowing FreeM programs to maintain two independent sets of identically- or differently-named local variables per process.
4150:
4151: The default symbol table is @code{0}, and the alternate symbol table is @code{1}, corresponding to the valid values for @code{^$JOB($JOB,"SYMTAB")}.
4152:
4153: Setting this subscript to values other than @code{0} or @code{1} will result in a @code{ZINVEXPR} error.
4154:
4155: @item @code{$PDISPLAY} +R -U -D
4156: Returns the value of @code{$PDISPLAY} for the job.
4157:
4158: @item @code{$PRINCIPAL} +R -U -D
4159: Returns the value of @code{$PRINCIPAL} for the job.
4160:
4161: @item @code{$TLEVEL} +R -U -D
4162: Returns the current transaction level (value of @code{$TLEVEL} for the job.
4163:
4164: @item @code{$IO} +R -U -D
4165: Returns the current value of @code{$IO} for the job.
4166:
4167: @item @code{USER} +R -U -D
4168: Returns the UID of the user owning the job.
4169:
4170: @item @code{GROUP} +R -U -D
4171: Returns the GID of the group owning the job.
4172:
4173: @item @code{NAMESPACE} +R +U -D
4174: Returns or sets the name of the job's currently-active namespace.
4175:
4176: @item @code{MATH} +R +U -D
4177: Returns or sets the mode in which decimal comparisons and arithmetic calculations are conducted. Valid values are @code{FIXED}, for fixed-point decimals having up to 20,000 digits of precision, as determined by the @code{$ZPRECISION} intrinsic special variable, and @code{IEEE754}, to use IEEE 754 floating-point decimals. When in @code{IEEE754} mode, floating-point numbers support up to 16 digits of numeric precision.
4178:
4179: @code{IEEE754} mode will make mathematical calculations significantly faster, especially when accelerated by a floating-point processor, at the expense of precision and accuracy.
4180:
4181: @code{FIXED} mode is recommended for financial calculations, or where precision and accuracy are valued over performance. @code{FIXED} is the default mode of FreeM operation.
4182:
4183: Attempting to @code{SET} this node to values other than @code{FIXED} or @code{IEEE754} will set @code{$ECODE} to @code{M29}.
4184:
4185: @end table
4186:
4187: @node ^$LOCK
4188: @section ^$LOCK
4189: @cindex ^$LOCK
4190: @cindex structured system variables, ^$LOCK
4191:
4192: The first-level subscript of @code{^$LOCK} is a lock name. The value at each node is the PID which owns the lock, a comma, and the lock counter for the locked resource.
4193:
4194: Attempting to @code{SET} or @code{KILL} any node in @code{^$LOCK} will raise error @code{M29}.
4195:
4196: @node ^$OBJECT
4197: @section ^$OBJECT
4198: @cindex ^$OBJECT
4199: @cindex structured system variables, ^$OBJECT
4200:
4201: @node ^$ROUTINE
4202: @section ^$ROUTINE
4203: @cindex ^$ROUTINE
4204: @cindex structured system variables, ^$ROUTINE
4205:
4206: The @code{^$ROUTINE} SSVN exposes a list of routines available in the current FreeM namespace, as well as additional attributes further describing each routine.
4207:
4208: The first-level subscript is the name of a FreeM routine minus the leading caret symbol.
4209:
4210: The following second-level subscripts are supported:
4211:
4212: @table @asis
4213:
4214: @item @code{CHARACTER} +R -U -D
4215: Returns the character set of the routine.
4216:
4217: @item @code{NAMESPACE} +R -U -D
4218: Returns the name of the FreeM namespace in which the routine resides.
4219:
4220: @item @code{PATH} +R -U -D
4221: Returns the full filesystem path to the routine in fixed storage.
4222:
4223: @end table
4224:
4225: @node ^$SYSTEM
4226: @section ^$SYSTEM
4227: @cindex ^$SYSTEM
4228: @cindex structured system variables, ^$SYSTEM
4229:
4230: The @code{^$SYSTEM} SSVN exposes system-level implementation details.
4231:
4232: The following first-level subscripts are supported:
4233:
4234: @table @asis
4235:
4236: @item @code{DEFPSIZE} +R -U -D
4237: Returns the default size in bytes of the symbol table and routine buffer memory partition.
4238:
4239: @item @code{DEFUDFSVSIZ} +R -U -D
4240: Returns the default size in bytes of the user-defined intrinsic special variable table.
4241:
4242: @item @code{DEFNSIZE} +R -U -D
4243: Returns the default size of the @code{NEW} stack, in number of entries.
4244:
4245: @item @code{MAXNO_OF_RBUF} +R -U -D
4246: Returns the maximum number of routine buffers.
4247:
4248: @item @code{DEFNO_OF_RBUF} +R -U -D
4249: Returns the default number of routine buffers.
4250:
4251: @item @code{DEFPSIZE0} +R -U -D
4252: Returns the default size in bytes of each routine buffer.
4253:
4254: @item @code{NO_GLOBLS} +R -U -D
4255: Returns the maximum number of globals that can be concurrently opened.
4256:
4257: @item @code{NO_OF_GBUF} +R -U -D
4258: Returns the number of global buffers.
4259:
4260: @item @code{NESTLEVLS} +R -U -D
4261: Returns the depth of the @code{DO}, @code{FOR}, @code{XECUTE} stack.
4262:
4263: @item @code{PARDEPTH} +R -U -D
4264: Returns the maximum depth of the parser's parameter stack.
4265:
4266: @item @code{PATDEPTH} +R -U -D
4267: Returns the maximum number of @emph{patatom}s in each pattern.
4268:
4269: @item @code{TRLIM} +R -U -D
4270: Returns the trace limit of the @code{BUILTIN} global handler.
4271:
4272: @item @code{ARGS_IN_ESC} +R -U -D
4273: Returns the maximum number of arguments in a terminal escape sequence.
4274:
4275: @item @code{ZTLEN} +R -U -D
4276: Returns the maximum length of @code{$ZTRAP}.
4277:
4278: @item @code{FUNLEN} +R -U -D
4279: Returns the maximum length of the @code{$ZF} (function key) variable.
4280:
4281: @item @code{NAME_LENGTH} +R -U -D
4282: Returns the maximum length of variable names in the current FreeM build. Compatible with the same SSVN node in @emph{Reference Standard M}
4283:
4284: @item @code{STRING_MAX} +R -U -D
4285: Returns the maximum length of character strings in the current FreeM build. Compatible with the same SSVN node in @emph{Reference Standard M}
4286:
4287: @item @code{$NEXTOK} +R -U -D
4288: Returns a value indicating whether or not the @code{$NEXT} intrinsic function is allowed. In FreeM, @code{$NEXT} is always enabled, and this SSVN is provided solely for compatibility with @emph{Reference Standard M}. Thus, this SSVN node always returns @code{1}.
4289:
4290: @item @code{EOK} +R -U -D
4291: Returns a value indicating whether or not @code{E} notation for exponents is allowed. In FreeM, this feature is always enabled, and this SSVN is provided solely for compatibility with @emph{Reference Standard M}. Thus, this SSVN node always returns @code{1}.
4292:
4293: @item @code{OFFOK} +R -U -D
4294: Returns a value indicating whether or not offsets are allowed in @code{DO} and @code{GOTO}. In FreeM, this feature is always enabled, and this SSVN is provided solely for compatibility with @emph{Reference Standard M}. Thus, this SSVN node always returns @code{1}.
4295:
4296: @item @code{BIG_ENDIAN} +R -U -D
4297: Returns a 1 if FreeM is running on a big-endian platform, or a 0 otherwise. Compatible with the same SSVN node in @emph{Reference Standard M}.
4298:
4299: @item @code{NAMESPACE} +R -U -D
4300: The descendant subscripts of this node list each namespace in the current FreeM environment.
4301:
4302: @item @code{MAPPINGS,GLOBAL} +R -U -D
4303: Descendant subscripts of this node represent global name mappings set in @code{^$GLOBAL(@emph{gvn},"NAMESPACE")}
4304:
4305: @end table
4306:
4307: @node ^$WINDOW
4308: @section ^$WINDOW
4309: @cindex ^$WINDOW
4310: @cindex structured system variables, ^$WINDOW
4311:
4312: The @code{^$WINDOW} SSVN has no nodes yet defined. However, completing a @code{MERGE} to this SSVN will cause MWAPI-ish things to happen, and further work is proceeding on MWAPI implementation.
4313:
4314: @node ^$ZPROCESS
4315: @section ^$ZPROCESS
4316: @cindex ^$ZPROCESS
4317: @cindex structured system variables, ^$ZPROCESS
4318:
4319: Provides access to @code{procfs}, which is a filesystem-like abstraction for UNIX process metadata contained in @code{/proc}, as well as features for examining and controlling the state of processes external to the FreeM interpreter.
4320:
4321: The first subscript always represents the @emph{process ID} of the external process being acted upon.
4322:
4323: The following values for the second subscript are supported:
4324:
4325:
4326: @table @asis
4327:
4328: @item @code{EXISTS} +R -U -D
4329: Returns 1 if the referenced process exists; 0 otherwise.
4330:
4331: @item @code{ATTRIBUTE} +R -U -D
4332: Exposes the @code{/proc} files as descendant subscripts, i.e., @code{WRITE ^$ZPROCESS(2900,"ATTRIBUTE","cmdline"),!} would print the initial command line used to invoke process ID 2900. Note that the third subscript (the immediate descendant of the @code{ATTRIBUTE} subscript) is case sensitive.
4333:
4334: @item @code{SIGNAL} -R +U -D
4335: Allows signals to be sent to the referenced process. The following subscript is an integer value corresponding to the desired signal number. You may obtain a list of signal numbers on most UNIX systems with the command @code{kill -l}.
4336:
4337: The constants @code{%SYS.SIGNAL.HUP}, @code{%SYS.SIGNAL.INT}, @code{%SYS.SIGNAL.KILL}, and @code{%SYS.SIGNAL.TERM} are provided for convenient use of this SSVN subscript.
4338:
4339: @end table
4340:
4341: @node ^$ZRPI
4342: @section ^$ZRPI
4343: @cindex ^$ZRPI
4344: @cindex structured system variables, ^$ZRPI
4345:
4346: The @code{^$ZRPI} structured system variable provides easy access to general-purpose input/output (GPIO) pins on Raspberry Pi single-board computers.
4347:
4348: To initialize the GPIO subsystem, @code{SET ^$ZRPI("INITIALIZE")=1}.
4349:
4350: Individual pins are accessed through @code{^$ZRPI("GPIO",<pin>,...)}, where @code{<pin>} represents the desired pin number. Descendant subscripts of @code{^$ZRPI("GPIO",<pin>)} are as follows:
4351:
4352: @table @asis
4353:
4354: @item @code{MODE} +R +U -D
4355: Represents the operating mode of the selected pin. One of @code{INPUT}, @code{OUTPUT}, @code{PWM_OUTPUT}, or @code{GPIO_CLOCK}.
4356:
4357: @item @code{DIGITAL} +R +U -D
4358: Reads or writes the selected pin digitally. The value is limited to @code{1} or @code{0}.
4359:
4360: @item @code{ANALOG} +R +U -D
4361: Reads or writes the selected pin in an analog fashion. The value represents analog voltage.
4362:
4363: @end table
4364:
4365: @node Operators
4366: @chapter Operators
4367:
4368: @menu
4369: * Unary +:: Force a value to positive.
4370: * Unary -:: Force a value to negative.
4371: * +:: Add.
4372: * +=:: Add and assign.
4373: * ++:: Postfix increment.
4374: * -:: Subtract.
4375: * -=:: Subtract and assign.
4376: * --:: Postfix decrement.
4377: * *:: Multiply.
4378: * *=:: Multiply and assign.
4379: * /:: Divide.
4380: * /=:: Divide and assign.
4381: * \:: Integer divide.
4382: * \=:: Integer divide and assign.
4383: * #:: Modulo.
4384: * #=:: Modulo and assign.
4385: * **:: Exponentiate.
4386: * **=:: Exponentiate and assign.
4387: * <:: Less than.
4388: * <=:: Less than or equal to.
4389: * >:: Greater than.
4390: * >=:: Greater than or equal to.
4391: * _:: Concatenate.
4392: * _=:: Concatenate and assign.
4393: * =:: Equals.
4394: * [:: Contains.
4395: * ]:: Follows.
4396: * ]]:: Sorts after.
4397: * ?:: Pattern match.
4398: * &:: Logical AND.
4399: * ! (Operator):: Logical OR.
4400: * ':: Logical NOT.
4401: * @@ (Operator):: Indirect
4402: @end menu
4403:
4404: @node Unary +
4405: @section Unary +
4406: @cindex operators, unary +
4407:
4408: Forces a number to positive, whether positive or negative. Also forces numeric coercion of strings.
4409:
4410: @node Unary -
4411: @section Unary -
4412: @cindex operators, unary -
4413:
1.28 snw 4414: Forces a number to negative, whether positive or negative. Also forces numeric coercion of strings.
4415:
1.1 snw 4416: @node +
4417: @section + (Add)
4418: @cindex operators, +
4419:
1.28 snw 4420: @emph{Syntax}
4421:
4422: @example
4423: S X=1+2 ; => 3
4424: @end example
4425:
4426: Adds numbers together.
4427:
1.1 snw 4428: @node +=
4429: @section += (Add/Assign)
4430: @cindex operators, +=
4431:
1.28 snw 4432: @emph{Syntax}
4433:
4434: @example
4435: S X=5
4436: S X+=3 ; => 8
4437: @end example
4438:
4439: Increments the variable on the LHS by the value on the RHS.
4440:
1.1 snw 4441: @node ++
4442: @section ++ (Postfix Increment)
4443: @cindex operators, ++
4444:
1.28 snw 4445: Increments a variable by 1.
4446:
1.1 snw 4447: @node -
4448: @section - (Subtract)
4449: @cindex operators, -
4450:
1.28 snw 4451: Subtracts one number from another.
4452:
1.1 snw 4453: @node -=
4454: @section -= (Subtract/Assign)
4455: @cindex operators, -=
4456:
1.28 snw 4457: @emph{Syntax}
4458:
4459: @example
4460: S X=5
4461: S X-=3 ; => 2
4462: @end example
4463:
4464: Decrements the variable on the LHS by the value on the RHS.
4465:
1.1 snw 4466: @node --
4467: @section -- (Postfix Decrement)
4468: @cindex operators, --
4469:
1.28 snw 4470: Decrements the variable by one.
4471:
1.1 snw 4472: @node *
4473: @section * (Multiply)
4474: @cindex operators, *
4475:
1.28 snw 4476: Multiplies one number by another.
4477:
1.1 snw 4478: @node *=
4479: @section *= (Multiply/Assign)
4480: @cindex operators, *=
4481:
1.28 snw 4482:
4483:
1.1 snw 4484: @node /
4485: @section / (Divide)
4486: @cindex operators, /
4487:
4488: @node /=
4489: @section /= (Divide/Assign)
4490: @cindex operators, /=
4491:
4492: @node \
4493: @section \ (Integer Divide)
4494: @cindex operators, \
4495:
4496: @node \=
4497: @section \= (Integer Divide/Assign)
4498: @cindex operators, \=
4499:
4500: @node #
4501: @section # (Modulo)
4502: @cindex operators, #
4503:
4504: @node #=
4505: @section #= (Modulo/Assign)
4506: @cindex operators, #=
4507:
4508: @node **
4509: @section ** (Exponentiate)
4510: @cindex operators, **
4511:
4512: @node **=
4513: @section **= (Exponentiate/Assign)
4514: @cindex operators, **=
4515:
4516: @node <
4517: @section < (Less Than)
4518: @cindex operators, <
4519:
4520: @node <=
4521: @section <= (Less Than or Equal To)
4522: @cindex operators, <=
4523:
4524: @node >
4525: @section > (Greater Than)
4526: @cindex operators, >
4527:
4528: @node >=
4529: @section >= (Greater Than or Equal To)
4530: @cindex operators, >=
4531:
4532: @node _
4533: @section _ (Concatenate)
4534: @cindex operators, _
4535:
4536: @node _=
4537: @section _= (Concatenate/Assign)
4538: @cindex operators, _=
4539:
4540: @node =
4541: @section = (Equals)
4542: @cindex operators, =
4543:
4544: @node [
4545: @section [ (Contains)
4546: @cindex operators, [
4547:
4548: @node ]
4549: @section ] (Follows)
4550: @cindex operators, ]
4551:
4552: @node ]]
4553: @section ]] (Sorts After)
4554: @cindex operators, ]]
4555:
4556: @node ?
4557: @section ? (Pattern Match)
4558: @cindex operators, ?
4559:
4560: @node &
4561: @section & (Logical AND)
4562: @cindex operators, &
4563:
4564: @node ! (Operator)
4565: @section ! (Logical OR)
4566: @cindex operators, !
4567:
4568: @node '
4569: @section ' (Logical NOT)
4570: @cindex operators, '
4571:
4572: @node @@ (Operator)
4573: @section @@ (Indirect)
4574: @cindex operators, @@
4575:
4576: @node Routines
4577: @chapter Routines
4578: @cindex routines
4579:
4580: A @emph{routine} is a file containing M source code to be processed by FreeM.
4581:
4582: Routines exist within a @emph{namespace} (such as @code{SYSTEM} or @code{USER}), which in turn exist within an @emph{environment} (such as @code{DEFAULT}).
4583:
4584: @menu
4585: * Routine Naming:: Requirements and conventions for routine names.
4586: @end menu
4587:
4588:
4589: @node Routine Naming
4590: @section Routine Naming
4591: The routine's filename follows the format @code{NAME.m}, where @code{NAME} is the name of the routine, and @code{.m} is the filename extension.
4592:
4593: Routine naming rules are as follows:
4594:
4595: @itemize @bullet
4596: @item Routine names must begin with an upper- or lower-case letter, or a @code{%} sign
4597: @item Within the routine name, you may have upper-case or lower-case letters or digits
4598: @item The entire routine name must not be longer than 255 characters
4599: @end itemize
4600:
4601: Routines whose names begin with @code{%} must be located in the @code{SYSTEM} namespace. Other routines may be located in any namespace.
4602:
4603: @node Types
4604: @chapter Types
4605: @cindex types
4606: @cindex data types
4607:
4608: FreeM supports all @emph{libdatatype} types defined in the former MDC's @emph{Millennium Draft Standard}, with the exception of @code{MATRIX}, and with extensions supporting object-oriented programming. A notable enhancement in FreeM is that the library data types can be used in the @emph{formallist} of any extrinsic function or subroutine; not only in @emph{libraryelement}s.
4609:
4610: @menu
4611: * BOOLEAN:: Truth values.
4612: * COMPLEX:: Numbers with real and imaginary parts.
4613: * INTEGER:: Numbers with no decimal part.
4614: * REAL:: Numbers with a decimal part.
4615: * STRING:: Arbitrary strings of characters.
4616: * Custom Types (Classes):: User-defined, object-oriented types.
4617: @end menu
4618:
4619: @node BOOLEAN
4620: @section BOOLEAN
4621: @cindex data types, BOOLEAN
4622: @cindex types, BOOLEAN
4623:
4624: The @code{BOOLEAN} type represents any M value that can be interpreted as a truth-value.
4625:
4626: @node COMPLEX
4627: @section COMPLEX
4628: @cindex data types, COMPLEX
4629: @cindex types, COMPLEX
4630:
4631: The @code{COMPLEX} type is a complex number represented as a string in the format @code{@emph{<real-part>}%@emph{<imaginary-part>}}, where @emph{real-part} and @emph{imaginary-part} are both @code{REAL} numbers. See @ref{REAL} for more information.
4632:
4633: FreeM will attempt to interpret any @code{COMPLEX} value according to the usual rules for M canonical numbers, i.e., the string @code{sabc123.345%fbd3.1} would be interpreted as a complex number with the real part being @code{123.345} and the imaginary part being @code{3.1}.
4634:
4635: @node INTEGER
4636: @section INTEGER
4637: @cindex data types, INTEGER
4638: @cindex types, INTEGER
4639:
4640: An @code{INTEGER} is an interpretation of numeric data with any fractional part removed.
4641:
4642: @node REAL
4643: @section REAL
4644: @cindex data types, REAL
4645: @cindex types, REAL
4646:
1.29 snw 4647: A @code{REAL} is a numeric interpretation of data including a fractional part.
4648:
1.1 snw 4649: @node STRING
4650: @section STRING
4651: @cindex data types, STRING
4652: @cindex types, STRING
4653:
1.36 snw 4654: The @code{STRING} is the fundamental FreeM data type. Other types are inferred from the context of their usage.
4655:
4656: @subsection String Rules
4657:
4658: The following rules apply to all FreeM strings:
4659:
4660: @itemize
4661: @item Must not exceed 255 characters
4662: @item Must not contain @code{$C(0)}, @code{$C(201)}, or @code{$C(202)}
4663: @end itemize
4664:
4665: @subsection String Quoting Rules
4666: Strings in FreeM must be surrounded in double quotes:
4667:
4668: @example
4669: SET MYSTRING="This is a string literal"
4670: @end example
4671:
4672: If you want to include double quotes inside of a string, simply double them:
4673:
4674: @example
4675: SET MYSTRING="This is a ""string literal"" with embedded double quotes"
4676: @end example
4677:
1.29 snw 4678:
1.1 snw 4679: @node Custom Types (Classes)
4680: @section Custom Types (Classes)
4681: @cindex data types, custom
4682: @cindex types, custom
4683: @cindex classes
4684:
1.44 snw 4685: See @ref{Object-Oriented Programming}.
1.1 snw 4686:
4687: @node Globals
4688: @chapter Globals
4689: @cindex globals
4690: @cindex variables, global
4691: @cindex data
4692:
1.33 snw 4693: @menu
4694: * Globals Overview:: Basics of FreeM persistent storage.
4695: * Creating Globals:: How to create globals.
4696: * Removing Globals:: How to remove globals.
4697: * Global Storage:: How globals are stored.
4698: @end menu
4699:
4700: @node Globals Overview
4701: @section Globals Overview
4702:
1.31 snw 4703: FreeM supports typical M globals, which are often described as persistent, hierachical sparse arrays. Globals make it relatively simple to include persistent data in an application without requiring the developer to use an external database management system, and offer syntax and semantics so similar to M local variables and structured system variables that moving from one to the other is seamless.
4704:
4705: Each global comprises three elements:
4706:
4707: @itemize @bullet
4708: @item
4709: An alphabetic name beginning with a caret (@code{^}) or a caret and a percent sign (@code{^%})
4710: @item
4711: Optionally, one or more comma-delimited subscripts, enclosed in parentheses
4712: @item
4713: A value of up to 255 characters in length
4714: @end itemize
4715:
1.36 snw 4716: A leading percent sign in the global name will force the named global into the @code{SYSTEM} namespace of the current FreeM environment.
1.31 snw 4717:
4718: @node Creating Globals
4719: @section Creating Globals
4720: @cindex globals, creating
4721:
4722: To create a global, you can use the @code{SET} command:
4723:
4724: @example
4725: SET ^MYGLOBAL("foo","bar")="this is the data value"
4726: @end example
4727:
4728: @node Removing Globals
4729: @section Removing Globals
4730: @cindex globals, removing
4731:
4732: To remove an entire global, you can use the @code{KILL} command with the unsubscripted name of the global:
4733:
4734: @example
4735: KILL ^MYGLOBAL
4736: @end example
4737:
4738: If you only want to remove part of a global, i.e., beginning at a certain subscript level, use the @code{KILL} command with a subscripted name:
4739:
4740: @example
4741: KILL ^MYGLOBAL("foo")
4742: @end example
4743:
4744: This will remove only the @code{"foo"} subscript and all of its children.
4745:
4746: If you only want to remove the data value at a specific subscript level, leaving the subscript itself intact, use @code{KVALUE}:
4747:
4748: @example
4749: KVALUE ^MYGLOBAL("foo")
4750: @end example
4751:
4752: @node Global Storage
4753: @section Global Storage
4754: @cindex globals, storage
4755:
4756: FreeM globals are stored in @code{$PREFIX/var/freem/@emph{<environment-name>}/@emph{<namespace-name>}/globals} in a binary format.
4757:
4758: Global files have a header of the following format:
4759:
4760: @verbatim
4761: typedef struct global_header {
4762:
4763: char magic[5]; /* FRMGL */
4764: int format_version;
4765: char host_triplet[40];
4766: char host_id[256];
4767:
4768: unsigned long block_size;
4769: unsigned long last_transaction_id;
4770:
4771: long created;
4772: long last_backup;
4773:
4774: } global_header;
4775: @end verbatim
4776:
1.1 snw 4777: @node Concurrency Control
4778: @chapter Concurrency Control
4779: @cindex concurrency control
4780: @cindex locking
4781: @cindex transaction processing
4782:
1.33 snw 4783: @menu
4784: * Concurrency Control Overview:: Basics of concurrency control.
4785: * Advisory Locks:: Coordinating access voluntarily.
4786: * Transaction Processing:: Ensuring logical consistency.
4787: @end menu
4788:
4789: @node Concurrency Control Overview
4790: @section Concurrency Control Overview
4791:
1.34 snw 4792: Multitasking, multi-user FreeM applications must concern themselves with conscientious management of concurrent access to globals in order to maintain logical consistency and prevent concurrent reads and writes from conflicting with each other.
1.31 snw 4793:
1.34 snw 4794: In FreeM, there are two mechanisms provided for managing concurrent global access: @emph{advisory locks}, and @emph{transaction processing}.
4795:
4796: Advisory locks allow applications to voluntarily coordinate concurrent access to globals with the @code{LOCK} command, and require each application to check the @code{LOCK} status prior to accessing a global.
4797:
4798: Transaction processing allows applications to delineate sets of global operations (sets, kills, etc.) as being part of a transaction, in which no operations are performed against the globals contained within the transaction until the transaction is committed. In addition, processes other than the one running the transaction will be forced to wait to access globals for either the duration of the commit phase (@emph{batch mode}), or for the entire duration of the transaction (@emph{serial mode}).
1.31 snw 4799:
1.33 snw 4800: @node Advisory Locks
4801: @section Advisory Locks
4802:
1.31 snw 4803: @node Transaction Processing
4804: @section Transaction Processing
4805: @cindex transaction processing
4806:
1.39 snw 4807: FreeM implements a significant subset of the transaction processing features from @emph{ANSI X11.1-1995}. This allows a series of global operations to be conducted all at once, either in batch mode (where concurrent operation is not interrupted until the last possible moment), or in serial mode (where writes are guaranteed to be atomic, consistent, isolated, and durable).
1.31 snw 4808:
4809: @subsection Theory of Operation
4810:
4811: FreeM uses a pessimistic concurrency control mechanism for @code{SERIAL} transactions, meaning that any @code{TSTART} command that includes the @code{SERIAL} transaction parameter will cause the process to acquire the transaction processing mutex, which prevents any process but the one holding the mutex from performing any data access (read or write) until either @code{TCOMMIT} or @code{TROLLBACK} is called, either committing or rolling back the transaction, respectively.
4812:
4813: Any transaction in between its @code{TSTART} and @code{TCOMMIT}/@code{TROLLBACK} is said to be @emph{in-flight}. During the in-flight stage, pending global operations are held only in memory and after-image journals.
4814:
4815: FreeM maintains a list of all globals affected during a transaction in-flight. When a @code{TCOMMIT} is reached, FreeM will generate a @emph{checkpoint} of each global data file to be changed by the transaction. These checkpoints allow all FreeM globals to be restored to their pre-transaction state if a @code{TCOMMIT} should fail part of the way through its operation.
4816:
4817: Checkpoints can have one of two modes:
4818:
4819: @table @asis
4820:
4821: @item @code{CP_REMOVE}
4822: Used for globals that did not exist prior to the beginning of this transaction. Simply marks the entire global data file for deletion in case of @code{TCOMMIT} failure.
4823:
4824: @item @code{CP_RESTORE}
4825: Used for globals that @emph{did} exist prior to the beginning of this transaction. In this case, the entire global data file is copied to a new file with a @code{.chk} extension. In cases of @code{TCOMMIT} failure, @code{CP_RESTORE} checkpoint files will be restored over the partially-modified live data file.
4826:
4827: @end table
4828:
4829: The below example shows a few global operations and checkpoints for a transaction in-flight using the @code{trantab} direct-mode command:
4830:
4831: @verbatim
4832: TL1:DEFAULT.USER> trantab
4833: $TLEVEL 1*
4834: Operations for Transaction ID: 6ea14aad-b8f1-47f9-9f52-4f513f892bc0 [RESTARTABLE SERIAL]
4835:
4836: OP. NO. ACTION KEY/DATA
4837: ------- ------ --------
4838: 1 SET ^FOO=3
4839: 2 KILL ^FOO
4840: 3 SET ^snw=10
4841: 4 SET ^BRANDNEW=6
4842:
4843: Global checkpoints:
4844:
4845: GLOBAL MODE FILES
4846: ------ ---- -----
4847: ^BRANDNEW CP_REMOVE IN: /usr/local/var/freem/USER/globals/^BRANDNEW
4848: ^snw CP_RESTORE IN: /usr/local/var/freem/USER/globals/^snw
4849: OUT: /usr/local/var/freem/USER/globals/^snw.23390.1.chk
4850: ^FOO CP_RESTORE IN: /usr/local/var/freem/USER/globals/^FOO
4851: OUT: /usr/local/var/freem/USER/globals/^FOO.23390.1.chk
4852: @end verbatim
4853:
4854: In the above example, @code{IN} files are the live data file that will be overwritten or removed, and @code{OUT} files are the checkpoints themselves. Note that @code{OUT} files are only used for @code{CP_RESTORE} checkpoints.
4855:
4856: @subsection Using Transaction Processing
4857:
4858: To use transactions in FreeM, you need to be familiar with three commands:
4859:
4860: @itemize @bullet
4861: @item
4862: @code{TSTART}
4863: @item
4864: @code{TCOMMIT}
4865: @item
4866: @code{TROLLBACK}
4867: @end itemize
4868:
4869: With transaction processing, global variable operations occurring between @code{TSTART} and @code{TCOMMIT} commands will be contained within the transaction.
4870:
4871: The atomicity, consistency, isolation, and durability facets of FreeM transaction hinge on the transaction mode.
4872:
4873: @subsubsection BATCH Transactions
4874: @code{BATCH} transactions offer higher performance, and allow other applications aside from the one doing the transaction to continue normal operations until the transaction is committed with @code{TCOMMIT}. In batch mode, other processes are only locked out of normal operation during the commit phase of the transaction.
4875:
4876: The effect of this is that the operations within the batch transaction will not be interleaved with global writes from other applications, but the entire lifetime of the transaction is not guaranteed to be serialized with respect to the transaction processing activities of other running applications in the environment.
4877:
4878: @subsubsection SERIAL Transactions
4879: @code{SERIAL} transactions offer full ACID compliance at the expense of multiprocessing performance. In serial mode, a @code{TSTART} blocks all activity from all other FreeM processes in the environment, and this blocking effect is not released until the transaction is committed with @code{TCOMMIT} or rolled back with @code{TROLLBACK} (or due to abnormal conditions in the environment that preclude the successful completion of the transaction).
4880:
1.1 snw 4881: @node Local Variables
4882: @chapter Local Variables
4883: @cindex variables, local
4884: @cindex local variables
4885:
1.41 snw 4886: @menu
4887: * Local Variables Overview:: The basics of locals.
4888: * Creating Local Variables:: Creating locals with SET.
4889: * Removing Local Variables:: Removing locals with KILL.
4890: @end menu
4891:
4892: @node Local Variables Overview
1.38 snw 4893: @section Local Variables Overview
4894:
4895: FreeM @emph{local variables} have the same data structure as global variables, but are scoped to a single FreeM process, and stored in memory.
4896:
4897: Each local comprises three elements:
4898:
4899: @itemize @bullet
4900: @item
4901: An alphabetic name beginning with a letter or a percent sign (@code{%})
4902: @item
4903: Optionally, one or more comma-delimited subscripts, enclosed in parentheses
4904: @item
4905: A value of up to 255 characters in length
4906: @end itemize
4907:
4908: @node Creating Local Variables
4909: @section Creating Local Variables
4910: @cindex local variables, creating
4911:
4912: To create a local variable, use the @code{SET} command:
4913:
4914: @example
4915: SET MYLOCAL("foo","bar")="this is the data value"
4916: @end example
4917:
4918: @node Removing Local Variables
4919: @section Removing Local Variables
4920: @cindex local variables, removing
4921:
4922: To remove an entire local variable, you can use the @code{KILL} command with the unsubscripted name of the variable:
4923:
4924: @example
4925: KILL MYLOCAL
4926: @end example
4927:
4928: If you only want to remove part of a local variable, i.e., beginning at a certain subscript level, use the @code{KILL} command with a subscripted name:
4929:
4930: @example
4931: KILL MYLOCAL("foo")
4932: @end example
4933:
4934: This will remove only the @code{"foo"} subscript and all of its children.
4935:
4936: If you only want to remove the data value at a specific subscript level, leaving the subscript itself intact, use @code{KVALUE}:
4937:
4938: @example
4939: KVALUE MYLOCAL("foo")
4940: @end example
4941:
1.1 snw 4942: @node Scoping
4943: @chapter Scoping
4944: @cindex scoping
4945:
1.38 snw 4946: By default, FreeM local variables and their values are scoped to the entire process, meaning that any function or subroutine can access and modify their values. This can lead to pernicious bugs.
4947:
4948: M provides the @code{NEW} command to work around these issues. When @code{NEW} is called with a local variable as its argument, FreeM will scope the variable to the process stack frame in which the @code{NEW} command occured. When exiting the stack frame (i.e. with the @code{QUIT} command), FreeM will restore the variable to its value prior to being @code{NEW}ed.
4949:
1.39 snw 4950: @emph{Example}
4951:
4952: @example
4953: MYRTN ;
4954: S J=1 ; set local variable J to 1
4955: W J,! ; this will output "1"
4956: D X ; execute subroutine X
4957: W J,! ; this will output "1", as the value of J was restored
4958: Q
4959: ;;
4960: X ;
4961: N J ; stack J
4962: S J=6 ; set its value to 6
4963: W J,! ; this will output "6"
4964: Q ; quit from the subroutine, destroying its stack frame
4965: ;;
4966: @end example
4967:
4968: @section Scoping Considerations for $TEST
4969:
4970: In M, the truth value of comparisons, logic operations, and certain forms of @code{LOCK} is stored in the @code{$TEST} intrinsic special variable, which follows the same rules as any M local variable.
4971:
4972: This is probably the most significant design flaw of the language, as the side effects of logic on @code{$TEST} lead to incredibly difficult bugs. However, M allows @code{$TEST} to be @code{NEW}ed, and FreeM provides the @code{THEN} command@footnote{From MDC Type A extension X11/1998-31} to help in the case of conditionals. @code{THEN} stacks @code{$TEST} to the end of the line.
4973:
4974: When writing new M code in FreeM, we strongly suggest using @code{THEN} as follows:
4975:
4976: @example
4977: MYRTN ;
4978: IF MYVAR=1 THEN DO SUBRT
4979: @end example
4980:
4981: This is instead of the traditional form:
4982:
4983: @example
4984: MYRTN ;
4985: IF MYVAR=1 DO SUBR
4986: @end example
4987:
4988: @cartouche
4989: @quotation
1.40 snw 4990: @emph{Style Recommendation}
1.39 snw 4991:
4992: Note that @code{THEN} is not in any currently published version of the @emph{Standard}, but is part of MDC Type A extension X11/1998-31. However, we recommend using @code{THEN} instead of favoring portability, as there is no defensible reason for this incredibly simple feature @emph{not} to be ubiquitous.
4993:
4994: If you use other M implementations, you should bug the implementers to implement @code{THEN}, as it at least partially mitigates an inexcusable flaw in the design of M.
4995: @end quotation
4996: @end cartouche
4997:
1.1 snw 4998: @node Decision Constructs
4999: @chapter Decision Constructs
5000: @cindex decision constructs
5001: @cindex IF
5002: @cindex ELSE
5003: @cindex THEN
5004: @cindex postconditionals
5005:
5006: @node Branch Constructs
5007: @chapter Branch Constructs
5008: @cindex branch constructs
5009: @cindex DO
5010: @cindex GOTO
5011: @cindex JOB
5012:
5013: @node Loop Constructs
5014: @chapter Loop Constructs
5015: @cindex loop constructs
5016: @cindex FOR
5017:
5018: @node Modular Programming
5019: @chapter Modular Programming
5020: @cindex modular programming
5021: @cindex functions, extrinsic
5022: @cindex subroutines
5023:
1.2 snw 5024: @menu
5025: * Subroutines:: Making sections of code reusable.
5026: * Extrinsic Functions:: Reusable code that returns a value.
5027: @end menu
5028:
1.1 snw 5029: @node Subroutines
5030: @section Subroutines
5031:
5032: @node Extrinsic Functions
5033: @section Extrinsic Functions
5034:
5035: @node Object-Oriented Programming
5036: @chapter Object-Oriented Programming
5037: @cindex object-oriented programming
5038: @cindex programming, object-oriented
5039:
1.45 snw 5040: @menu
5041: * Classes:: The organizing concept of object-oriented programming.
5042: * Inheritance:: Making one class derive from another.
5043: * Methods:: Attach code to classes.
5044: * Public and Private Variables:: Determining accessibility.
5045: * Instantiating Objects:: Creating instances of classes.
5046: @end menu
1.2 snw 5047:
1.45 snw 5048: @node Classes
1.1 snw 5049: @section Classes
1.33 snw 5050: @subsection Class Overview
5051:
1.29 snw 5052: A @emph{class} is the primary organizing concept of FreeM support for object-oriented programming, and in FreeM, is simply an M routine with a few special properties:
5053:
5054: @example
5055: MYCLASS(THIS,INIT):OBJECT ; Constructor for MYCLASS, inherits OBJECT
5056: ; two private variables
5057: S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
5058: S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
5059: Q
5060: ;
5061: DESTROY(THIS) ; This is the destructor
5062: Q
5063: @end example
5064:
5065: The above example demonstrates general class syntax.
5066:
5067: @subsection Constructors
5068:
5069: A @emph{constructor} is an M entry point that is called when a new instance of a class is created.
5070:
5071: A constructor must be the first entry point in a class routine, its tag must match the class/routine name, and it must take two arguments, @code{THIS} and @code{INIT}.
5072:
5073: @code{THIS} represents the instance of the object being accessed, and @code{INIT} represents an initializer that can be used to assign an initial value to the object when instantiating the class.
5074:
5075: A constructor looks like this:
5076:
5077: @example
5078: %FRACTION(THIS,INIT):OBJECT ;
5079: S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
5080: S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
5081: Q
5082: @end example
5083:
5084: @emph{Syntax}
5085: @example
5086: @emph{<class-name>}(THIS,INIT)[:@emph{<superclass>}]
5087: @end example
5088:
5089: In the above example, @emph{<superclass>} represents the name of a class from which this class should inherit. In this case, the @code{FRACTION} class inherits from the @code{OBJECT} class. Note that this is not strictly necessary in this case, as all classes in FreeM automatically inherit from @code{OBJECT}.
5090:
5091: @subsection Destructors
5092: A @code{destructor} is called when you @code{KILL} an instance variable. Its tag must be @code{DESTROY}, and it must take one argument (@code{THIS}).
5093:
5094: The destructor should be used to clean up any resources used by class methods.
5095:
5096: A destructor looks like this:
5097:
5098: @example
5099: DESTROY(THIS) ;
5100: ; free any resources that should be freed at the end of the object's lifetime
5101: Q
5102: @end example
1.2 snw 5103:
1.45 snw 5104: @node Inheritance
1.29 snw 5105: @section Inheritance
5106:
5107: Every class you create will automatically inherit the methods and functionality of the @code{OBJECT} class, supplied with FreeM.
5108:
5109: When attempting to call a method, FreeM will first search the class routine for a matching entry point, and then follow the inheritance chain upwards until a matching entry point is found. If the final class in the chain does not have a matching entry point, FreeM will try to find a matching entry point in the @code{OBJECT} class.
5110:
5111: Inheritance is achieved by specifying the name of the superclass in the constructor:
5112:
5113: @example
5114: CLASS(THIS,INIT):SUPERCLASS
5115: @end example
5116:
5117: @subsection Runtime Polymorphism
5118:
5119: You can achieve runtime polymorphism by subclassing, and defining methods in the subclass that match the names of existing methods in the superclass. Following FreeM inheritance rules, the overridden method in the subclass will be called, and the method in the superclass will not.
5120:
5121: Note that the overridden method in the subclass can take a different set or number of arguments than the @emph{formallist} of the superclass method would specify.
1.1 snw 5122:
1.45 snw 5123: @node Methods
1.29 snw 5124: @section Methods
5125: Class methods are defined as tags with @emph{formallist}s in a class routine, and per the typical FreeM object pattern, must take at least one argument, being @code{THIS} (representing a reference to the object instance being accessed).
1.1 snw 5126:
1.29 snw 5127: The following class (@code{MYCLASS}) has a constructor, a destructor, and a method called @code{MYMETHOD}:
5128:
5129: @example
5130: %MYCLASS(THIS,INIT) ;
5131: Q THIS
5132: DESTROY(THIS) ;
5133: Q
5134: MYMETHOD(THIS) ;
5135: Q "VALUE"
5136: @end example
5137:
1.31 snw 5138: The dot operator is used to invoke class methods:
5139:
5140: @example
5141: DEFAULT.USER> N MYOBJ=$#^%MYCLASS("")
5142: DEFAULT.USER> W MYOBJ.MYMETHOD()
5143: VALUE
5144: @end example
5145:
1.45 snw 5146: @node Public and Private Variables
1.29 snw 5147: @section Public and Private Variables
5148:
1.30 snw 5149: FreeM supports private fields with the @code{:PRIVATE} specifier in the @code{SET} command, enforcing classical object-oriented data encapsulation. The @code{:PUBLIC} specifier is provided for completeness, and is the default.
1.29 snw 5150:
5151: The below constructor for a @code{FRACTION} class defines two private fields:
5152:
5153: @example
5154: %FRACTION(THIS,INIT):OBJECT ;
5155: S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
5156: S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
5157: Q
5158: @end example
5159:
5160: Either of the following commands will create a public field:
5161:
5162: @example
5163: S THIS("VARNAM")="Initial Value"
5164: S THIS("VARNAM"):PUBLIC="Initial Value"
5165: @end example
1.1 snw 5166:
1.29 snw 5167: Attempting to access private fields from outside of the class will raise error condition @code{ZOBJFLDACCV}.
1.1 snw 5168:
1.45 snw 5169: @node Instantiating Objects
1.31 snw 5170: @section Instantiating Objects
5171:
5172: To instantiate an object (i.e., create an object from a certain class), you will use the @code{NEW} command as follows:
5173:
5174: @example
5175: NEW MYSTR=$#^%STRING("myString")
5176: @end example
5177:
5178: This will create a local variable called MYSTR of type STRING, and initialize it with the value myString.
5179:
1.45 snw 5180: @subsection Determining Object Class
1.31 snw 5181:
5182: To determine the class of any FreeM local variable, you will use the @code{$$TYPE()} method:
5183:
5184: @example
5185: USER> W MYSTR.$$TYPE()
5186: ^%STRING
5187: @end example
5188:
5189: The @code{$$TYPE()} method is a member of the @code{OBJECT} class.
5190:
1.1 snw 5191: @node Libraries
5192: @chapter Libraries
5193: @cindex libraries
5194:
5195: @node Sequential I/O
5196: @chapter Sequential I/O
5197:
5198: @node Network I/O
5199: @chapter Network I/O
5200: @cindex networks, input and output
5201:
5202: Network I/O in FreeM is supplied through I/O channels 100-255. The normal @code{READ} and @code{WRITE} syntax will work with network sockets, with a few exceptions.
5203:
5204: @section Opening and Connecting a Client Socket
5205: @cindex networks, opening and connecting client sockets
5206:
5207: To open a client socket and connect to it, you will need to call the @code{OPEN} command and the @code{USE} command:
5208:
5209: @example
5210: ;
5211: ; Set socket read terminator to LF
5212: ;
5213: SET ^$DEVICE(100,"OPTIONS","TERMINATOR")=$C(10)
5214: ;
5215: ; Open an IPv4 TCP socket to mail.mydomain.com on port 25 (SMTP)
5216: ; and connect to it
5217: ;
5218: OPEN 100:"mail.mydomain.com:25:IPV4:TCP"
5219: USE 100:/CONNECT
5220: ;
5221: ; Read a line of input from the remote host and write it to the terminal
5222: ;
5223: NEW LINE
5224: READ LINE
5225: USE 0
5226: WRITE LINE,!
5227: ;
5228: ; CLOSE the socket and disconnect
5229: ;
5230: CLOSE 100
5231: QUIT
5232: @end example
5233:
5234: @node Extended Global References
5235: @chapter Extended Global References
5236: @cindex global references, extended
5237: @cindex extended global references
5238:
5239: @section Standard Extended Global References
5240: @cindex extended global references, standard
5241:
5242: FreeM supports extended global references, allowing the user to access globals in namespaces other than the current default namespace and the @code{SYSTEM} namespace, without switching to the other namespace.
5243:
5244: For example, if you are in the @code{USER} namespace, the following code will print the value of @code{^VA(200,0)} in the @code{VISTA} namespace:
5245:
5246: @example
5247: WRITE ^|"VISTA"|VA(200,0),!
5248: @end example
5249:
5250: You may also use an expression that resolves to a string containing a valid namespace name:
5251:
5252: @example
5253: SET NS="VISTA"
5254: WRITE ^|NS|VA(200,0),!
5255: @end example
5256:
5257: @node Global Aliasing
5258: @chapter Global Aliasing
5259: @cindex aliasing, global
5260: @cindex globals, aliasing
5261:
5262: FreeM provides the ability to set alternative names for M global variables.
5263:
5264: To create an alias of @code{^FOO} named @code{^BAR}, use the following command:
5265:
5266: @example
5267: SET ^$JOB($JOB,"ALIASES","^BAR")="^FOO"
5268: @end example
5269:
5270: If such an alias is set, any reference to global variable @code{^BAR} will affect @code{^FOO} instead of @code{^BAR} until @code{^$JOB($JOB,"ALIASES","^BAR")} is @code{KILL}ed. If @code{^BAR} existed prior to the definition of this alias, its data will be unavailable to and unaffected by application code.
5271:
5272: @node Global Mappings
5273: @chapter Global Mappings
5274: @cindex mappings, global
5275: @cindex globals, mapping
5276:
5277: FreeM supports creating persistent mappings through which arbitrary global names may be mapped to specific namespaces. This allows non-@code{%} globals to be stored in the @code{SYSTEM} namespace, or @code{%} globals to be stored in non-@code{SYSTEM} namespaces.
5278:
5279: To map the @code{^FOO} global to the @code{SYSTEM} namespace, any of the following will work:
5280:
5281: @example
5282: MAP GLOBAL ^FOO="SYSTEM"
5283: SET ^$GLOBAL("FOO","NAMESPACE")="SYSTEM"
5284: SET ^$SYSTEM("MAPPINGS","GLOBAL","^FOO")="SYSTEM"
5285: @end example
5286:
5287: There is no functional difference in any of the three approaches; the method you choose is a matter of personal preference.
5288:
5289: To remove the above mapping, any of the following examples will also work:
5290:
5291: @example
5292: UNMAP GLOBAL ^FOO
5293: KILL ^$GLOBAL("FOO","NAMESPACE")
5294: KILL ^$SYSTEM("MAPPINGS","GLOBAL","^FOO")
5295: @end example
5296:
5297:
5298:
5299: @node Asynchronous Event Handling
5300: @chapter Asynchronous Event Handling
5301: @cindex event handling, asynchronous
5302:
5303: Asynchronous event handling in FreeM follows the specifications of the unpublished MDC @emph{Millennium Draft Standard}.
5304:
5305: @section Setting Up Async Event Handlers
5306:
5307: Asynchronous event handlers are configured through the @code{^$JOB} structured system variable for job-specific events, and the @code{^$SYSTEM} structured system variable for system-wide events. In order to become proficient in writing asynchronous event handling code, you need to be aware of several important concepts:
5308:
5309: @table @emph
5310:
5311: @item Event Classes
5312: @emph{Event classes} denote particular categories of events. These include @code{COMM}, @code{HALT}, @code{IPC}, @code{INTERRUPT}, @code{POWER}, @code{TIMER}, @code{TRIGGER}, and @code{USER} event classes. At present, only @code{INTERRUPT} and @code{TRIGGER} event classes are supported.
5313:
5314: @item Event Identifiers
5315: @emph{Event identifiers} denote the precise nature of the event that has occurred. For instance, resizing the terminal window in which a FreeM job is running will send an event of class @code{INTERRUPT} with an event identifier of @code{SIGWINCH} (short for @emph{SIGnal WINdow CHange}).
5316:
5317: @item Event Handlers
5318: @emph{Event handlers} are M routines or subroutines that can be registered to run when an event of a certain event class occurs.
5319:
5320: @item Event Registration
5321: @emph{Event registration} is the process of modifying the @code{^$JOB} or @code{^$SYSTEM} SSVN to associate a particular event class and event identifier with an event handler routine or subroutine.
5322:
5323: @item Event Blocking and Unblocking
5324: @emph{Event blocking} is the means by which asynchronous event handling can be temporarily suspended. For example, asynchronous events are temporarily and implicitly blocked for the duration of event handler execution, unless explicitly un-blocked within the event handler. Event handling can also be blocked and unblocked programatically from M code using the @code{ABLOCK} and @code{AUNBLOCK} commands.
5325:
5326: @end table
5327:
5328: The following sections of this chapter will take you step-by-step through setting up an event handler for @code{SIGWINCH} signal handling.
5329:
5330: @section Registering an Asynchronous Event Handler
5331: @cindex event handlers, registration
5332:
5333: To register a job-specific event handler that will only execute in the current FreeM process, use the following syntax:
5334:
5335: @example
5336: SET ^$JOB($JOB,"EVENT",@emph{event-class},@emph{event-identifier})=@emph{entryref}
5337: @end example
5338:
5339: To register a system-wide event handler that will execute in every FreeM process, use the following syntax:
5340:
5341: @example
5342: SET ^$SYSTEM("EVENT",@emph{event-class},@emph{event-identifier})=@emph{entryref}
5343: @end example
5344:
5345: For example, use the following to register @code{^RESIZE} as an asynchronous event handler for @code{SIGWINCH} events:
5346:
5347: @example
5348: SET ^$JOB($JOB,"EVENT","INTERRUPT","SIGWINCH")="^RESIZE"
5349: @end example
5350:
5351: This by itself will not enable asynchronous event handling, as it merely @emph{registers} an event handler, associating it with event class @code{INTERRUPT} and event identifier @code{SIGWINCH}.
5352:
5353: @section Enabling Asynchronous Event Handling
5354: @cindex event handlers, enabling
5355:
5356: In order to enable asyncronous event handling, the @code{ASTART} command is used. In the following example, we will enable asynchronous event handling for the @code{INTERRUPT} event class:
5357:
5358: @example
5359: ASTART "INTERRUPT"
5360: @end example
5361:
5362: Omitting the @code{"INTERRUPT"} argument will enable asynchronous event handling for @emph{all} event classes. See @code{ASTART} in the commands section for more details.
5363:
5364: Once this is done, any event handlers registered for the @code{INTERRUPT} event class in @code{^$JOB} will be executed asynchronously as appropriate.
5365:
5366: Please note that @code{ASTART "TRIGGER"} is run implicitly at FreeM startup, to ensure consistency in applications depending on business logic contained in system-wide global triggers. To disable this behavior, add @code{ASTOP "TRIGGER"} to the @code{LOCAL.STARTUP} routine in the @code{USER} namespace. If @code{LOCAL.STARTUP} does not yet exist in your environment, you may create it by typing @code{fmadm edit routine USER LOCAL.STARTUP} from your UNIX command-line shell.
5367:
5368: @section Disabling Asynchronous Event Handling
5369: @cindex event handlers, disabling
5370:
5371: To disable asynchronous event handling, the @code{ASTOP} command is used. In the following example, we will disable asynchronous event handling for the @code{INTERRUPT} event class:
5372:
5373: @example
5374: ASTOP "INTERRUPT"
5375: @end example
5376:
5377: Omitting the @code{"INTERRUPT"} argument will disable asynchronous event handling for @emph{all} event classes. See @code{ASTOP} in the commands section for more details.
5378:
5379: You may also disable asynchronous event handling for a specific event identifier by @code{KILL}ing the appropriate node in the @code{^$JOB} SSVN, which unregisters the event handler altogether. The following example will unregister the event handler for the @code{SIGWINCH} event identifier:
5380:
5381: @example
5382: KILL ^$JOB($JOB,"EVENT","INTERRUPT","SIGWINCH")
5383: @end example
5384:
5385: @section Temporarily Blocking Asynchronous Event Handling
5386: @cindex event handlers, blocking
5387:
5388: To temporarily block processing of specific event classes, you will use the @code{ABLOCK} command. @code{ABLOCK} functions incrementally, that is, each successive call to @code{ABLOCK} will increment a counter of blocks held for the specified event class or classes, and each successive call to @code{AUNBLOCK} will decrement that counter. Event handling for the specified event classes will be blocked as long as the @code{ABLOCK} counter for those classes is greater than zero. Thus, event blocking is cumulative, in a manner similar to M incremental locks.
5389:
5390: The following example blocks asynchronous event handling for the @code{INTERRUPT} event class:
5391:
5392: @example
5393: ABLOCK "INTERRUPT"
5394: @end example
5395:
5396: Note that entering an event handler causes an implicit @code{ABLOCK} of @emph{all} event classes, to prevent event handlers from interrupting other event handlers during their execution. This may be overridden by calling @code{AUNBLOCK} for one or more event classes within an event handler. However, unblocking event handling during an event handler should be done with great caution, as this can make the flow of code execution somewhat unpredictable, especially if M globals are modified inside of an event handler routine or subroutine.
5397:
5398: Modifying M globals within event handlers is allowed but strongly discouraged, as doing so can lead to logical corruption of the data. If you must modify an M global within an event handler, guard all such operations with prodigious and careful use of @code{LOCK}s, ensuring that such modifications occur in the desired logical order.
5399:
5400: @node Global Triggers
5401: @chapter Global Triggers
5402: @cindex global triggers
5403: @cindex triggers
5404:
5405: Global triggers use the FreeM asynchronous event handling subsystem to allow a FreeM process to execute arbitrary M code when a particular action occurs on a particular global.
5406:
5407: To set up a global trigger, you must set up an event handler for event class @code{TRIGGER}. The event identifier must be in the format of @code{"<action>:<gvn>"}, where @emph{<gvn>} is a global variable name, and @emph{<action>} is one of the following:
5408:
5409: @table @asis
5410:
5411: @item @code{DATA}
5412: Trigger will fire when the @code{$DATA} intrinsic function is called on @emph{<gvn>}.
5413:
5414: @item @code{GET}
5415: Trigger will fire when @emph{<gvn>} is read from.
5416:
5417: @item @code{INCREMENT}
5418: Trigger will fire when intrinsic function @code{$INCREMENT} is called on @emph{<gvn>}.
5419:
5420: @item @code{KILL}
5421: Trigger will fire when @emph{<gvn>} is @code{KILL}ed.
5422:
5423: @item @code{NEXT}
5424: Trigger will fire when intrinsic function @code{$NEXT} is called on @emph{<gvn>}.
5425:
5426: @item @code{ORDER}
5427: Trigger will fire when intrinsic function @code{$ORDER} is called on @emph{<gvn>}.
5428:
5429: @item @code{QUERY}
5430: Trigger will fire when intrinsic function @code{$QUERY} is called on @emph{<gvn>}.
5431:
5432: @item @code{SET}
5433: Trigger will fire when @code{SET @emph{<gvn>}=@emph{value}} occurs.
5434:
5435: @item @code{ZDATA}
5436: Trigger will fire when intrinsic function @code{ZDATA} is called on @emph{<gvn>}.
5437:
5438: @end table
5439:
5440: When a @code{TRIGGER} event occurs, the @code{"GLOBAL"} node of the @code{^$EVENT} structured system variable will be populated with the global reference that invoked the trigger event.
5441:
5442: If a @code{SET} or @code{KILL} trigger was the source of the @code{TRIGGER} event, the @code{OLD_VALUE} node of @code{^$EVENT} will be populated with original value of @code{^$EVENT("GLOBAL")} prior to the change, and @code{NEW_VALUE} will be populated with the new value. This allows triggers to contain logic to undo global changes. This functionality can also be used to provide auditing of specific global changes.
5443:
5444: The following example shows a trigger implemented for @code{SET} operations on the @code{^DD} global.
5445:
5446: @example
5447: TRIGGER ;
5448: ;
5449: ; Set up a SET trigger on ^DD
5450: ;
5451: SET ^$JOB($JOB,"EVENT","TRIGGER","SET:^DD")="ONSET^TRIGGER"
5452: ;
5453: ; Enable the TRIGGER event class
5454: ;
5455: ASTART "TRIGGER"
5456: ;
5457: ; Try setting a node in ^DD
5458: ;
5459: SET ^DD(1)="Test"
5460: ;
5461: ; Quit
5462: ;
5463: QUIT
5464: ;
5465: ;
5466: ONSET ;
5467: WRITE "The "_^$EVENT("GLOBAL")_" global node was SET.",!
5468: QUIT
5469: @end example
5470:
5471: You can also set up a trigger that applies to all FreeM processes by setting descendant subscripts of @code{^$SYSTEM("EVENT","TRIGGER",...)} instead of using @code{^$JOB($JOB,"EVENT","TRIGGER",...)}.
5472:
5473: @node Synchronous Event Handling
5474: @chapter Synchronous Event Handling
5475:
5476: @node GUI Programming with MWAPI
5477: @chapter GUI Programming with MWAPI
5478:
5479: @node User-Defined Z Commands
5480: @chapter User-Defined Z Commands
5481:
5482: @node User-Defined Z Functions
5483: @chapter User-Defined Z Functions
5484:
5485: @cindex z functions, user-defined
5486:
5487: @node User-Defined SSVNs
5488: @chapter User-Defined SSVNs
5489:
5490: @cindex structured system variables, user-defined
5491: @cindex structured system variables
5492:
5493: @node Language Dialects
5494: @chapter Language Dialects
5495:
5496: @cindex language dialects
5497: @cindex dialects, language
5498:
5499:
5500: @node System Library Routines
5501: @chapter System Library Routines
5502: @cindex system library routines
5503:
5504: @section ^%ZCOLUMNS
5505: @cindex ^%ZCOLUMNS
5506: @cindex system library routines, ^%ZCOLUMNS
5507:
5508: This routine is the implementation of the @code{$ZCOLUMNS} intrinsic special variable.
5509:
1.28 snw 5510: @section %SYSINIT
5511: @cindex %SYSINIT
5512: @cindex system library routines, %SYSINIT
1.1 snw 5513:
5514: This routine is the default startup routine for FreeM running in direct mode.
5515:
5516: Running @code{DO INFO} from direct mode will use this routine to display information about the current FreeM status and namespace configuration.
5517:
5518: @section ^%ZHELP
5519: @cindex ^%ZHELP
5520: @cindex system library routines, ^%ZHELP
5521:
5522: This routine implements the online help feature of FreeM, invoked by typing @code{?} in direct mode. It simply asks the underlying system to execute the command @command{info freem}.
5523:
5524: @section ^%ZROWS
5525: @cindex ^%ZROWS
5526: @cindex system library routines, ^%ZROWS
5527:
5528: This routine is the implementation of the @code{$ZROWS} intrinsic special variable.
5529:
5530: @node Interrupt Handling
5531: @chapter Interrupt Handling
5532: @cindex interrupt handling
5533:
1.22 snw 5534: When FreeM receives the @code{SIGINT} signal, either by pressing @code{Ctrl-C} during program execution, or by external signal from the operating system, the FreeM environment daemon, or another external process, one of two things can happen, depending on the state of the @code{$ZI} special variable:
1.1 snw 5535:
5536: @table @asis
5537: @item @code{$ZI} evaluates @emph{true}
5538: In this case, the @code{ZINRPT} error is raised, and normal error handling procedures apply. If neither @code{$ZTRAP} nor @code{$ETRAP} are set, FreeM prints an error diagnostic on the home device and will exit the FreeM process in application mode (i.e., the @code{freem} executable was started with the @code{--routine} or @code{-r} flag), or return to the direct mode prompt otherwise.
5539:
5540: This is the default behavior of FreeM.
5541: @item @code{$ZI} evaluates @emph{false}
5542: In this case, no error is raised, but the @code{$ZCONTROLC} flag is set. In this mode of operation, it is up to program code to check for @code{$ZCONTROLC} and take appropriate action.
5543:
5544: Checking the value of @code{$ZCONTROLC} will reset it to @emph{false}.
5545: @end table
5546:
5547: In either case, if asynchronous event handling is enabled for the @code{INTERRUPT} event class (i.e., @code{ASTART "INTERRUPT"} or @code{ASTART} have been invoked by the current process), an asynchronous event of event class @code{INTERRUPT} and event identifier @code{SIGINT} will be enqueued.
5548:
5549: @node Error Processing
5550: @chapter Error Processing
5551: @cindex error processing
5552:
5553: FreeM exposes three means of processing M program execution errors:
5554:
5555: @table @emph
5556:
5557: @item FreeM-style error processing
5558: FreeM-style error processing exposes a read/write error trap in @code{$ZTRAP}. The contents of @code{$ZTRAP} must be either empty or a valid M entryref, to which FreeM will @code{GOTO} if an error occurs. Each program stack execution level can have its own @code{$ZTRAP} error handler enabled.
5559:
5560: @item DSM 2.0-style error processing
5561: DSM 2.0-style error processing emulates the @code{$ZTRAP} behavior of Digital Standard MUMPS v2. It has the same behavior as FreeM-style error handling, with the exception that in DSM 2.0-style error processing, only one @code{$ZTRAP} error handler is set across all program stack execution levels.
5562:
5563: @item Standard error processing
5564: Standard error processing uses the @code{NEW}-able @code{$ETRAP} variable to store error handler code, which may be any valid M code. The code in @code{$ETRAP} will run when an error occurs or the @code{$ECODE} ISV becomes non-empty. Stack information for standard error handling is provided by the @code{$STACK} ISV, the @code{$STACK()} intrinsic pseudo-function, and the @code{NEW}-able @code{$ESTACK} ISV.
5565:
5566: If @code{$ETRAP} is non-empty when an error condition occurs, @code{$ZTRAP} is ignored, regardless of whether FreeM-style or DSM 2.0-style error processing is enabled at the time of the error.
5567:
5568: @end table
5569:
5570: For further information on switching between FreeM-style and DSM 2.0-style @code{$ZTRAP} error handling, see the documentation for the @code{BREAK} command.
5571:
5572: @node FreeM Error Codes
5573: @chapter FreeM Error Codes
5574: @cindex Error Codes
5575:
5576: @table @asis
5577:
5578: @item @code{ZINRPT} - @emph{interrupt}
5579: Raised when an interrupt signal is received.
5580:
5581: @item @code{ZBKERR} - @emph{BREAK point}
5582: Raised when a @code{BREAK} point is reached.
5583:
5584: @item @code{ZNOSTAND} - @emph{non standard syntax}
5585: Raised when features incompatible with the current value of @code{$DIALECT} are used.
5586:
5587: @item @code{ZUNDEF} - @emph{variable not found}
5588: Raised when an undefined local or global variable is accessed. This error code has been deprecated in favor of standard error codes @code{M6} and @code{M7}.
5589:
5590: @item @code{ZLBLUNDEF} - @emph{label not found}
5591: Raised when a referenced label is not found.
5592:
5593: @item @code{ZMISSOPD} - @emph{missing operand}
5594: Raised when an operand is missing from an expression.
5595:
5596: @item @code{ZMISSOP} - @emph{missing operator}
5597: Raised when an operator is missing from an expression.
5598:
5599: @item @code{ZILLOP} - @emph{unrecognized operator}
5600: Raised when an unrecognized operator is encountered in an expression.
5601:
5602: @item @code{ZQUOTER} - @emph{unmatched quotes}
5603: Raised when unbalanced quotes are encountered.
5604:
5605: @item @code{ZCOMMAER} - @emph{comma expected}
5606: Raised when a comma is expected in program syntax but is not found.
5607:
5608: @item @code{ZASSIGNER} - @emph{equals '=' expected}
5609: Raised when an equals sign is expected in program syntax but is not found.
5610:
5611: @item @code{ZARGER} - @emph{argument not permitted}
5612: Raised when an argument is encountered in a syntactic position where arguments are not permitted.
5613:
5614: @item @code{ZSPACER} - @emph{blank ' ' expected}
5615: Raised when a space character is expected in program syntax but is not found.
5616:
5617: @item @code{ZBRAER} - @emph{unmatched parentheses}
5618: Raised when unbalanced parentheses are detected in program syntax.
5619:
5620: @item @code{ZLVLERR} - @emph{level error}
5621: Raised when a level error occurs.
5622:
5623: @item @code{ZDIVER} - @emph{divide by zero}
5624: Raised when program code attempts to divide by zero. Deprecated in favor of standard error code @code{M9}.
5625:
5626: @item @code{ZILLFUN} - @emph{function not found}
5627: Raised when program code attempts to call intrinsic or extrinsic functions that are not defined.
5628:
5629: @item @code{ZFUNARG} - @emph{wrong number of function arguments}
5630: Raised when an intrinsic or extrinsic function is called with the wrong number of arguments.
5631:
5632: @item @code{ZZTERR} - @emph{ZTRAP error}
5633: Raised when a @code{$ZTRAP} error occurs.
5634:
5635: @item @code{ZNEXTERR} - @emph{$NEXT/$ORDER error}
5636: Raised when an error occurs in @code{$NEXT} or @code{$ORDER}.
5637:
5638: @item @code{ZSELER} - @emph{$SELECT error}
5639: Raised when an error occurs in @code{$SELECT}
5640:
5641: @item @code{ZCMMND} - @emph{illegal command}
5642: Raised when program code attempts to execute an illegal command.
5643:
5644: @item @code{ZARGLIST} - @emph{argument list incorrect}
5645: Raised when the argument list supplied to an M language element does not match that language element's syntactic requirements.
5646:
5647: @item @code{ZINVEXPR} - @emph{invalid expression}
5648: Raised when an invalid expression is encountered.
5649:
5650: @item @code{ZINVREF} - @emph{invalid reference}
5651: Raised when an invalid variable reference is encountered.
5652:
5653: @item @code{ZMXSTR} - @emph{string too long}
5654: Raised when a string is encountered that exceeds @code{^$SYSTEM("STRING_MAX")}.
5655:
5656: @item @code{ZTOOPARA} - @emph{too many parameters}
5657: Raised when too many parameters are passed to a function or subroutine.
5658:
5659: @item @code{ZNOPEN} - @emph{unit not open}
5660: Raised when attempting to access an I/O channel that has not been opened.
5661:
5662: @item @code{ZNODEVICE} - @emph{unit does not exist}
5663: Raised when attempting to access a device that does not exist.
5664:
5665: @item @code{ZPROTECT} - @emph{file protection violation}
5666: Raised when attempting to access a file or device to which you do not have permission.
5667:
5668: @item @code{ZGLOBER} - @emph{global not permitted}
5669: Raised when attempting to use a global in a syntactic element where global variables are not permitted.
5670:
5671: @item @code{ZFILERR} - @emph{file not found}
5672: Raised when attempting to access a file that does not exist.
5673:
5674: @item @code{ZPGMOV} - @emph{program overflow}
5675: Raised when a program overflows the limits of a routine buffer.
5676:
5677: @item @code{ZSTKOV} - @emph{stack overflow}
5678: Raised when @code{DO}, @code{FOR}, or @code{XECUTE} nesting levels exceed the value in @code{^$SYSTEM("NESTLEVLS")}.
5679:
5680: @item @code{ZSTORE} - @emph{symbol table overflow}
5681: Raised when program code attempts to store too much data in the local symbol table. Should not occur unless symbol table auto-adjust is disabled.
5682:
5683: @item @code{ZNOREAD} - @emph{file won't read}
5684: Raised when program code attempts to read from an unreadable file.
5685:
5686: @item @code{ZNOWRITE} - @emph{file won't write}
5687: Raised when program code attempts to write to an unwritable file.
5688:
5689: @item @code{ZNOPGM} - @emph{routine not found}
5690: Raised when an attempt is made to load or execute a routine that does not exist in the current namespace.
5691:
5692: @item @code{ZNAKED} - @emph{illegal naked reference}
5693: Raised when an attempt is made to use an illegal naked reference.
5694:
5695: @item @code{ZSBSCR} - @emph{illegal subscript}
5696: Raised when an illegal subscript access is attempted.
5697:
5698: @item @code{ZISYNTX} - @emph{insert syntax}
5699: Raised when illegal insert syntax is used.
5700:
5701: @item @code{ZDBDGD} - @emph{global data degradation}
5702: Raised when corruption is detected in global data files.
5703:
5704: @item @code{ZKILLER} - @emph{job kill signal}
5705: Raised on a job kill signal.
5706:
5707: @item @code{ZHUPER} - @emph{hangup signal}
5708: Raised on a job hangup signal.
5709:
5710: @item @code{ZMXNUM} - @emph{numeric overflow}
5711: Raised when an assignment or expression result exceeds @code{$ZPRECISION}.
5712:
5713: @item @code{ZNOVAL} - @emph{function returns no value}
5714: Raised when a function does not return a value. Extrinsic functions must @code{QUIT} with a value.
5715:
5716: @item @code{ZTYPEMISMATCH} - @emph{type mismatch}
5717: Raised when a type mismatch occurs.
5718:
5719: @item @code{ZMEMOV} - @emph{out of memory}
5720: Raised when FreeM runs out of heap memory.
5721:
5722: @item @code{ZNAMERES} - @emph{error in name resolution}
5723: Raised when an attempted name resolution fails.
5724:
5725: @item @code{ZSCKCREAT} - @emph{error creating socket}
5726: Raised when an error occurs creating a socket for network I/O.
5727:
5728: @item @code{ZSCKIFAM} - @emph{invalid address family (must be IPV4 or IPV6)}
5729: Raised when the address family specified in an @code{OPEN} command for a socket I/O channel is not IPV4 or IPV6.
5730:
5731: @item @code{ZSCKITYP} - @emph{invalid connection type (must be TCP or UDP)}
5732: Raised when the connection type specified in an @code{OPEN} command for a socket I/O channel is not @code{TCP} or @code{UDP}.
5733:
5734: @item @code{ZSCKIPRT} - @emph{invalid port number}
5735: Raised when the port number specified in an @code{OPEN} command for a socket I/O channel is invalid. Valid TCP and UDP ports are in the range of 1-65535.
5736:
5737: @item @code{ZSCKCERR} - @emph{connection error}
5738: Raised when an error occurs on a @code{USE <channel>:/CONNECT} command.
5739:
5740: @item @code{ZSCKAERR} - @emph{USE action invalid for connection type (possibly CONNECT on UDP socket?)}
5741: Raised when an attempt is made to @code{USE <channel>:/CONNECT} on a UDP socket I/O channel. The UDP protocol is connectionless.
5742:
5743: @item @code{ZSCKACON} - @emph{attempted to CONNECT an already-connected socket}
5744: Raised when an attempt is made to @code{USE <channel>:/CONNECT} on a TCP socket I/O channel that is already connected.
5745:
5746: @item @code{ZSCKNCON} - @emph{attempted to READ from a disconnected TCP socket}
5747: Raised when an attempt is made to @code{READ} a TCP socket that has not yet been connected.
5748:
5749: @item @code{ZSCKEOPT} - @emph{error setting socket options}
5750: Raised when an error is encountered while setting socket options.
5751:
5752: @item @code{ZSCKERCV} - @emph{error in READ from socket}
5753: Raised when an error occurs in a socket I/O channel @code{READ}.
5754:
5755: @item @code{ZSCKESND} - @emph{error in WRITE to socket}
5756: Raised when an error occurs while attempting to @code{WRITE} to a socket I/O channel.
5757:
5758: @item @code{ZNORPI} - @emph{^$ZRPI only supported on Raspberry Pi hardware}
5759: Raised when an attempt is made to use the @code{^$ZRPI} structured system variable on a platform other than the Raspberry Pi single-board computer.
5760:
5761: @item @code{ZCREDEF} - @emph{cannot redefine CONST}
5762: Raised when attempts are made to redefine a @code{CONST} after its initial definition.
5763:
5764: @item @code{ZCMODIFY} - @emph{cannot modify CONST}
5765: Raised when attempts are made to change the value of a @code{CONST}.
5766:
5767: @item @code{ZFILEXWR} - @emph{cannot open existing file for WRITE}
5768: Raised when an attempt is made to open an existing file in write (but not append) mode.
5769:
5770: @item @code{INEWMULT} - @emph{initializing NEW with multiple setarguments not supported}
5771: Raised when you attempt to use multiple setarguments with initializing @code{NEW}, e.g. @code{NEW X=2,Y=3}.
5772:
5773: @item @code{ZECODEINV} - @emph{invalid value for $ECODE}
5774: Raised when attempts are made to set @code{$ECODE} to an invalid error code value. Obsolete and replaced by standard error code @code{M101}.
5775:
5776: @item @code{ZASSERT} - @emph{programmer assertion failed}
1.46 snw 5777: Raised when an @code{ZASSERT} expression's result is not true.
1.1 snw 5778:
5779: @item @code{ZUSERERR} - @emph{user-defined error}
5780: Raised when program code calls @code{THROW} with an error code argument for which the first character is @code{U}, or when @code{$ECODE} is set to an error code for which the first character is @code{U}.
5781:
5782: Custom error messages for @code{ZUSERERR} may be set in @code{^$JOB($JOB,"USER_ERRORS",<user_error_code>)}, where @code{<user_error_code>} represents the custom error code.
5783:
5784: For example:
5785:
5786: @example
1.22 snw 5787: DEFAULT.USER> S ^$JOB($JOB,"USER_ERRORS","UBLACKHOLE")="black hole encountered"
1.1 snw 5788:
5789:
1.22 snw 5790: DEFAULT.USER> THROW UBLACKHOLE
1.1 snw 5791:
5792:
5793: >> Error UBLACKHOLE: black hole encountered in SYSTEM::^%SYSINIT [$STACK = 0]
5794: >> THROW UBLACKHOLE
5795: ^
5796: @end example
5797:
5798: @item @code{ZSYNTERR} - @emph{syntax error}
5799: Raised when a syntax error without a more specific error code is encountered.
5800:
5801: @item @code{ZCTRLB} - @emph{break}
5802: Pseudo-error used by the FreeM debugger. Not visibly raised in normal program operation.
5803:
5804: @item @code{ZASYNC} - @emph{asynchronous interruption}
5805: Pseudo-error used by the FreeM asynchronous events subsystem. Not visibly raised in normal program operation.
5806:
5807: @item @code{M1} - @emph{naked indicator undefined}
5808: Raised when an attempt is made to use a naked reference before the naked indicator is set.
5809:
5810: @item @code{M2} - @emph{invalid combination with $FNUMBER code atom}
5811:
5812:
5813: @item @code{M3} - @emph{$RANDOM seed less than 1}
5814:
5815:
5816: @item @code{M4} - @emph{no true condition in $SELECT}
5817:
5818:
5819: @item @code{M5} - @emph{line reference less than zero}
5820:
5821:
5822: @item @code{M6} - @emph{undefined local variable}
5823:
5824:
5825: @item @code{M7} - @emph{undefined global variable}
5826:
5827:
5828: @item @code{M8} - @emph{undefined intrinsic special variable}
5829:
5830:
5831: @item @code{M9} - @emph{divide by zero}
5832:
5833:
5834: @item @code{M10} - @emph{invalid pattern match range}
5835:
5836:
5837: @item @code{M11} - @emph{no parameters passed}
5838:
5839:
5840: @item @code{M12} - @emph{invalid line reference (negative offset)}
5841:
5842:
5843: @item @code{M13} - @emph{invalid line reference (line not found)}
5844:
5845:
5846: @item @code{M14} - @emph{line level not 1}
5847:
5848:
5849: @item @code{M15} - @emph{undefined index variable}
5850:
5851:
5852: @item @code{M16} - @emph{argumented QUIT not allowed}
5853:
5854:
5855: @item @code{M17} - @emph{argumented QUIT required}
5856:
5857:
5858: @item @code{M18} - @emph{fixed length READ not greater than zero}
5859:
5860:
5861: @item @code{M19} - @emph{cannot copy a tree or subtree onto itself}
5862:
5863:
5864: @item @code{M20} - @emph{line must have a formal parameter list}
5865:
5866:
5867: @item @code{M21} - @emph{algorithm specification invalid}
5868:
5869:
5870: @item @code{M22} - @emph{SET or KILL to ^$GLOBAL when data in global}
5871:
5872:
5873: @item @code{M23} - @emph{SET or KILL to ^$JOB for non-existent job number}
5874:
5875:
5876: @item @code{M24} - @emph{change to collation algorithm while subscripted local variables defined}
5877:
5878:
5879: @item @code{M26} - @emph{non-existent environment}
5880:
5881:
5882: @item @code{M27} - @emph{attempt to rollback a transaction that is not restartable}
5883:
5884:
5885: @item @code{M28} - @emph{mathematical function, parameter out of range}
5886:
5887:
5888: @item @code{M29} - @emph{SET or KILL on structured system variable not allowed by implementation}
5889:
5890:
5891: @item @code{M30} - @emph{reference to global variable with different collating sequence within a collating algorithm}
5892:
5893:
5894: @item @code{M31} - @emph{control mnemonic used for device without a mnemonic space selected}
5895:
5896:
5897: @item @code{M32} - @emph{control mnemonic used in user-defined mnemonic space which has no associated line}
5898:
5899:
5900: @item @code{M33} - @emph{SET or KILL to ^$ROUTINE when routine exists}
5901:
5902:
5903: @item @code{M35} - @emph{device does not support mnemonic space}
5904:
5905:
5906: @item @code{M36} - @emph{incompatible mnemonic spaces}
5907:
5908:
5909: @item @code{M37} - @emph{READ from device identified by empty string}
5910:
5911:
5912: @item @code{M38} - @emph{invalid structured system variable subscript}
5913:
5914:
5915: @item @code{M39} - @emph{invalid $NAME argument}
5916:
5917:
5918: @item @code{M40} - @emph{call-by-reference in JOB actual parameter}
5919:
5920:
5921: @item @code{M41} - @emph{invalid LOCK argument within a transaction}
5922:
5923:
5924: @item @code{M42} - @emph{invalid QUIT within a transaction}
5925:
5926:
5927: @item @code{M43} - @emph{invalid range value ($X, $Y}
5928:
5929:
5930: @item @code{M44} - @emph{invalid command outside of a transaction}
5931:
5932:
5933: @item @code{M45} - @emph{invalid GOTO reference}
5934:
5935:
5936: @item @code{M56} - @emph{identifier exceeds maximum length}
5937:
5938:
5939: @item @code{M57} - @emph{more than one defining occurrence of label in routine}
5940:
5941:
5942: @item @code{M58} - @emph{too few formal parameters}
5943:
5944:
5945: @item @code{M60} - @emph{illegal attempt to use an undefined SSVN}
5946:
5947:
5948: @item @code{M101} - @emph{invalid value for $ECODE}
5949:
5950:
5951: @item @code{M102} - @emph{synchronous and asynchronous event processing cannot be simultaneously enabled for the same event class}
5952:
5953:
5954: @item @code{M103} - @emph{invalid event identifier}
5955:
5956:
5957: @item @code{M104} - @emph{ETRIGGER event identifier for IPC event class does not match job process identifier}
5958:
5959:
5960: @end table
5961:
1.35 snw 5962:
1.1 snw 5963: @node System Configuration
5964: @chapter System Configuration
5965: @cindex configuration, system
5966:
5967: @section Installing FreeM
5968: @cindex installation
5969:
1.35 snw 5970: @subsection Installation Methods
1.1 snw 5971:
1.35 snw 5972: FreeM allows the following installation methods:
1.1 snw 5973: @table @asis
1.35 snw 5974: @item Binary Repository
5975: On recent versions the Ubuntu and Debian distributions of GNU/Linux, we provide package repositories from which FreeM may easily be installed. See the @emph{FreeM Wiki} for more information, and @emph{https://packages.coherent-logic.com} for instructions.
1.1 snw 5976:
1.35 snw 5977: If available, this is the simplest method of installing FreeM.
5978: @item Binary Packages
5979: We provide binary packages of FreeM for @emph{dpkg} and @emph{rpm}-based distributions of GNU/Linux, and @emph{pkgadd} packages for Solaris 8-10. If you cannot use repositories, this is the easiest option.
5980:
5981: See @emph{https://freem.coherent-logic.com/binaries.cfm} for downloads and instructions.
5982: @item Source Archive
5983: If you prefer installing from source, we recommend that you download the latest @emph{.tar.gz} file from @emph{https://freem.coherent-logic.com/downloads.cfm}, and follow these steps:
5984:
5985: @example
5986: $ gunzip freem-@emph{<version>}.tar.gz
5987: $ tar xf freem-@emph{<version>}.tar
5988: $ cd freem
5989: $ ./configure # see the Build Configuration section for optional flags
5990: $ make
5991: $ sudo make install
5992: @end example
1.1 snw 5993:
1.35 snw 5994: Once this process has been completed, you may proceed to @emph{Initial Configuration}.
1.1 snw 5995:
1.35 snw 5996: Installation from source archive is the most challenging but flexible supported option for advanced users.
5997: @item CVS Repository
5998: If you wish to try the bleeding-edge development version of FreeM, you may do so by following these steps:
1.1 snw 5999:
1.35 snw 6000: @verbatim
6001: $ cvs -d :pserver:anonymous@cvs.coherent-logic.com:/home/cvsroot co freem
6002: $ cd freem
6003: $ ./autogen.sh
6004: $ ./configure # see the Build Configuration section for optional flags
1.1 snw 6005: $ make
6006: $ sudo make install
1.35 snw 6007: @end verbatim
6008:
6009: Once this process has been completed, you may proceed to @emph{Initial Configuration}.
6010:
6011: This installation method is by far the most complicated, and is intended only for those who wish to contribute to FreeM development. It is not intended for end users, and no technical support will be provided.
6012:
6013: See the @emph{Contributor Guide} on the @emph{FreeM Wiki} for more information.
6014: @end table
6015: @subsection Build Configuration
6016: @cindex build configuration
6017:
6018: When configuring FreeM with the supplied @code{configure} script, there are some FreeM-specific options that may be used to compile in optional features, or exclude default ones:
6019:
6020: @table @asis
1.1 snw 6021:
1.35 snw 6022: @item @code{--enable-mwapi} (EXPERIMENTAL)
6023: Enables experimental support for the M Windowing API (ANSI @emph{X11.6-1995}) using the OSF/Motif widget toolkit. Requires that you have the @code{X11}, @code{Xt}, @code{ICE}, and @code{Xm} libraries, as well as all of their C header files.
1.1 snw 6024:
6025: Please consult your operating system's documentation for the correct commands to install the required libraries.
6026:
6027: @emph{Example}
6028:
6029: @example
1.35 snw 6030: $ ./configure --enable-mwapi
1.1 snw 6031: $ make
6032: $ sudo make install
6033: @end example
6034:
1.35 snw 6035: @end table
1.1 snw 6036:
1.35 snw 6037: @subsection Initial Configuration
6038: Once FreeM is installed, you will need to configure it:
1.1 snw 6039:
1.35 snw 6040: @enumerate
6041: @item Create a user and group, each named @emph{freem}, under which FreeM will run
6042: @item Add any user accounts that will need to run FreeM to the @emph{freem} group
6043: @item Have all users added in step 2 sign out and sign in for the new group membership to take effect
6044: @item Run @code{fmadm configure} with superuser privileges to create the @code{DEFAULT} environment with @code{SYSTEM} and @code{USER} namespaces and default after-image journal settings, and populate the bundled vendor routines
6045: @item Run @code{fmadm start environment} with superuser privileges to start the @code{DEFAULT} environment
6046: @item Make sure the environment is ready by running @code{fmadm status environment} with superuser privileges
6047: @end enumerate
6048:
6049: @subsubsection Creating Additional Environments
6050: To create additional environments, do the following steps:
6051:
6052: @enumerate
6053: @item Create a new user and group for the environment @emph{(optional)}
6054: @item Run @code{fmadm configure -e=@emph{<environment>} -u=@emph{<username>} -g=@emph{<groupname>} [-E=@emph{true|false}]} @emph{(the @code{-E} flag enables or disables the environment)}
6055: @item Run @code{fmadm start environment -e=@emph{<environment>}} to start the environment
6056: @item Run @code{fmadm status environment} to make sure the environment is healthy
6057: @end enumerate
1.1 snw 6058:
1.35 snw 6059: @subsubsection Additional Customization
1.1 snw 6060:
1.35 snw 6061: See the FreeM @emph{environment catalog} at @code{@emph{$PREFIX}/etc/freem/env.conf}, and the @emph{fmadm}(1) @code{man} page for more information.
1.1 snw 6062:
1.35 snw 6063: @emph{$PREFIX} represents the root location of your FreeM installation. This can be @code{/usr/local}, @code{/}, or others, depending on how FreeM was built and installed.
1.1 snw 6064:
6065: @node Accessing FreeM from C Programs
6066: @chapter Accessing FreeM from C Programs
6067:
6068: FreeM provides a library, @file{libfreem.so}, as well as corresponding header file @file{freem.h}, allowing C programmers to write programs that access FreeM globals, locals, structured system variables, subroutines, and extrinsic functions. This functionality can be used to implement language bindings and data access drivers for external systems.
6069:
6070: In order to be used in your C programs, your C programs must link with @file{libfreem.so} and include @file{freem.h}. This will allow your C code access to the function prototypes, data structures, and constants required for calling the @file{libfreem.so} APIs.
6071:
6072: You must exercise caution in developing programs that interface with FreeM through @file{libfreem.so} to ensure that all @file{libfreem.so} API calls are serialized, as FreeM and the @file{libfreem.so} library are neither thread-safe nor reentrant.
6073:
6074: You must also avoid setting signal handlers for @code{SIGALRM}, as FreeM uses @code{SIGALRM} to manage timeouts for @command{LOCK}, @command{READ}, and @command{WRITE}.
6075:
6076: @section freem_ref_t Data Structure
6077: @cindex libfreem, data structures: freem_ref_t
6078:
6079: The @code{libfreem} API uses a @code{struct} of type @code{freem_ref_t} in order to communicate state, pass in values, and return results.
6080:
6081: The data structure, defined in @file{freem.h}, looks like this:
6082:
6083: @verbatim
6084: typedef struct freem_ref_t {
6085:
6086: /*
6087: * The 'reftype' field can be one of:
6088: *
6089: * MREF_RT_LOCAL
6090: * MREF_RT_GLOBAL
6091: * MREF_RT_SSV
6092: */
6093: short reftype;
6094:
6095: /*
6096: * The 'name' field is the name of the local variable,
6097: * global variable, or SSVN (without ^ or ^$).
6098: */
6099: char name[256];
6100:
6101: /*
6102: * Returned data goes in a string, so you've got to figure out the
6103: * whole M canonical number thing yourself. Good luck. :-)
6104: */
6105: char value[STRLEN];
6106:
6107: short status;
6108:
6109: unsigned int subscript_count;
6110: char subscripts[255][256];
6111:
6112: } freem_ref_t;
6113: @end verbatim
6114:
6115: @emph{freem_ref_t Members}
6116:
6117: @table @asis
6118: @cindex libfreem, freem_ref_t.reftype
6119: @item @option{reftype}
6120: The @option{reftype} member determines whether we are operating on a local variable, a global variable, or a structured system variable. It may be set to any of following constants: @code{MREF_RT_LOCAL}, @code{MREF_RT_GLOBAL}, or @code{MREF_RT_SSV}.
6121:
6122: @cindex libfreem, freem_ref_t.name
6123: @item @option{name}
6124: The @option{name} member contains the name of the global, local, or SSVN to be accessed. You @emph{must not} include leading characters, such as @code{^} or @code{^$}.
6125:
6126: @cindex libfreem, freem_ref_t.value
6127: @item @option{value}
6128: This member contains the value read from or the value to be written to the global, local, or SSVN.
6129:
6130: @cindex libfreem, freem_ref_t.status
6131: @item @option{status}
6132: This member gives us various API status values after the API call returns. In general, this value is also returned by each API function.
6133:
6134: @cindex libfreem, freem_ref_t.subscript_count
6135: @item @option{subscript_count}
6136: The number of subscripts to be passed into the API function being called. This value represents the maximum index into the first dimension of the @code{subscripts} array.
6137:
6138: @cindex libfreem, freem_ref_t.subscripts
6139: @item @option{subscripts}
6140: A two-dimensional array containing the subscripts to which we are referring in this API call.
6141:
6142: @end table
6143:
6144: @section freem_ent_t Data Structure
6145: @cindex libfreem, data structures: freem_ent_t
6146:
6147: The @code{freem_function()} and @code{freem_procedure()} APIs in @code{libfreem} use the @code{freem_ent_t} struct in order to indicate the name of the entry point being called, any arguments being passed to it, and the return value of the called function (not used for @code{freem_procedure()}).
6148:
6149: The data structure, defined in @file{freem.h}, looks like this:
6150:
6151: @verbatim
6152: typedef struct freem_ent_t {
6153:
6154: /* name of function or procedure entry point */
6155: char name[256];
6156:
6157: /* return value */
6158: char value[STRLEN];
6159:
6160: /* value of ierr on return */
6161: short status;
6162:
6163: /* argument count and array */
6164: unsigned int argument_count;
6165: char arguments[255][256];
6166:
6167: } freem_ent_t;
6168: @end verbatim
6169:
6170: @emph{freem_ent_t Members}
6171:
6172: @table @asis
6173:
6174: @item @option{name}
6175: @cindex libfreem, freem_ent_t.name
6176: The @option{name} member contains the name of the extrinsic function or procedure to be called.
6177:
6178: @cindex libfreem, freem_ent_t.value
6179: @item @option{value}
6180: This member contains the value returned by the function called. Not used by @code{freem_procedure()}.
6181:
6182: @cindex libfreem, freem_ent_t.status
6183: @item @option{status}
6184: This member gives us the value of @code{ierr} after the function or procedure call returns. The possible values of @code{ierr} are listed in @code{merr.h}.
6185:
6186: @cindex libfreem, freem_ent_t.argument_count
6187: @item @option{argument_count}
6188: The number of arguments to be passed into the extrinsic function or procedure being called. This value represents the maximum index into the first dimension of the @code{arguments} array.
6189:
6190: @cindex libfreem, freem_ent_t.arguments
6191: @item @option{arguments}
6192: A two-dimensional array containing the arguments to be passed into the extrinsic function or procedure being called.
6193:
6194: @end table
6195:
6196: @section freem_init()
6197: @cindex libfreem, freem_init()
6198:
6199: Initializes @code{libfreem} in preparation for calling other APIs.
6200:
6201: @emph{Synopsis}
6202:
6203: @code{pid_t freem_init(char *environment_name, char *namespace_name);}
6204:
6205: @emph{Parameters}
6206:
6207: @table @asis
6208: @item @code{environment_name}
6209: Specifies the environment to use.
6210: @item @code{namespace_name}
6211: Specifies the namespace to use.
6212: @end table
6213:
6214: @emph{Return Values}
6215:
6216: Returns the process ID of the @code{libfreem} process on success, or @code{-1} on failure.
6217:
6218: @emph{Example}
6219:
6220: This example prompts the user to enter a FreeM namespace and then attempts to initialize @code{libfreem} to use the selected namespace.
6221:
6222: @verbatim
6223: #include <stdio.h>
6224: #include <string.h>
6225: #include <freem.h>
6226:
6227: int main(int argc, char **argv, char **envp)
6228: {
6229: char namespace[256];
6230:
6231: /* get the namespace name to use */
6232: printf("Enter FreeM namespace to use: ");
6233: fgets(namespace, 255, stdin);
6234:
6235: /* remove the trailing newline */
6236: namespace[strcspn(buffer, "\n")] = '\0';
6237:
6238: /* initialize libfreem using the provided namespace */
6239: if(freem_init("DEFAULT", namespace) == TRUE) {
6240: printf("\nSuccess\n");
6241: }
6242: else {
6243: printf("\nFailure\n");
6244: }
6245:
6246: return 0;
6247: }
6248: @end verbatim
6249:
6250: @section freem_version()
6251: @cindex libfreem, freem_version()
6252:
6253: Returns the version of FreeM in use.
6254:
6255: @emph{Synopsis}
6256:
6257: @code{short freem_version(char *result);}
6258:
6259: @emph{Parameters}
6260:
6261: @table @asis
6262: @item @code{result}
6263: The @code{result} parameter is a pointer to a buffer in which the FreeM version information will be returned. The caller must allocate memory for this buffer prior to calling this API. It should be at least 20 bytes in length.
6264: @end table
6265:
6266: @emph{Return Value}
6267:
6268: Returns @code{0}.
6269:
6270: @emph{Example}
6271:
6272: This example will display the FreeM version on standard output.
6273:
6274: @verbatim
6275: #include <stdio.h>
6276: #include <string.h>
6277: #include <freem.h>
6278:
6279: int main(int argc, char **argv, char **envp)
6280: {
6281: char version[20] = {0};
6282:
6283: freem_init(``USER'');
6284: freem_version(version);
6285:
6286: printf(``FreeM version: %s\n'', version);
6287:
6288: }
6289: @end verbatim
6290:
6291: @section freem_set()
6292: @cindex libfreem, freem_set()
6293:
6294: Sets a FreeM local node, global node, or writable SSVN node.
6295:
6296: @emph{Synopsis}
6297:
6298: @code{short freem_set(freem_ref_t *ref);}
6299:
6300: @emph{Parameters}
6301:
6302: @table @asis
6303: @item @code{freem_ref_t}
6304: This parameter is a pointer to a @code{freem_ref_t} struct. The caller must allocate the memory for this struct.
6305: @end table
6306:
6307: @emph{Return Value}
6308:
6309: Returns @code{OK} on success, or one of the other error values defined in @code{merr.h}.
6310:
6311: @emph{Example}
6312:
6313: This example sets the value @code{blue} into global node @code{^car("color")}.
6314:
6315: @verbatim
6316: #include <stdio.h>
6317: #include <string.h>
6318: #include <freem.h>
6319:
6320: int main(int argc, char **argv, char **envp)
6321: {
6322: freem_ref_t ref;
6323:
6324: /* we're setting a global */
6325: ref.reftype = MREF_RT_GLOBAL;
6326:
6327: /* access global "car" */
6328: strcpy(ref.name, "car");
6329:
6330: /* set up the subscripts */
6331: ref.subscript_count = 1;
6332: strcpy(ref.subscripts[0], "color");
6333:
6334:
6335: /* use the USER namespace */
6336: freem_init("USER");
6337:
6338: /* write the data out */
6339: freem_set(&ref);
6340:
6341: }
6342: @end verbatim
6343:
6344: @section freem_get()
6345: @cindex libfreem, freem_get()
6346:
6347: Retrieves a FreeM local node, global node, or writable SSVN node.
6348:
6349: @emph{Synopsis}
6350:
6351: @code{short freem_get(freem_ref_t *ref);}
6352:
6353: @emph{Parameters}
6354:
6355: @table @asis
6356: @item @code{freem_ref_t}
6357: This parameter is a pointer to a @code{freem_ref_t} struct. The caller must allocate the memory for this struct.
6358: @end table
6359:
6360: @emph{Return Value}
6361:
6362: Returns @code{OK} on success, or one of the other error values defined in @code{merr.h}.
6363:
6364: @emph{Example}
6365:
6366: This example retrieves the character set of the current process.
6367:
6368: @verbatim
6369: #include <stdio.h>
6370: #include <sys/types.h>
6371: #include <unistd.h>
6372: #include <string.h>
6373: #include <freem.h>
6374:
6375: int main(int argc, char **argv, char)
6376: {
6377: pid_t pid;
6378: freem_ref_t ref;
6379:
6380: /* get the PID of this process */
6381: pid = getpid();
6382:
6383: /* we want to access an SSVN */
6384: ref.reftype = MREF_RT_SSV;
6385:
6386: /* set up the name and subscripts */
6387: strcpy(ref.name, "JOB");
6388:
6389: ref.subscript_count = 2;
6390: sprintf(ref.subscripts[0], "%d", pid);
6391: strcpy(ref.subscripts[1], "CHARACTER");
6392:
6393: /* initialize libfreem, using the USER namespace */
6394: freem_init("USER");
6395:
6396: /* call libfreem API */
6397: freem_get(&ref);
6398:
6399: /* output the character set info */
6400: printf("PID %d character set is '%s'\n", pid, ref.value);
6401: }
6402: @end verbatim
6403:
6404: @section freem_kill()
6405: @cindex libfreem, freem_kill()
6406:
6407: Deletes a FreeM local node, global node, or killable SSVN node, as well as all of its children.
6408:
6409: @emph{short freem_kill(freem_ref_t *ref);}
6410:
6411: @emph{Parameters}
6412:
6413: @table @asis
6414: @item @code{freem_ref_t}
6415: This parameter is a pointer to a @code{freem_ref_t} struct. The caller must allocate the memory for this struct.
6416: @end table
6417:
6418: @emph{Return Value}
6419:
6420: Returns @code{OK} on success, or one of the other error values defined in @code{merr.h}.
6421:
6422: @emph{Example}
6423:
6424: @verbatim
6425: #include <stdio.h>
6426: #include <string.h>
6427: #include <freem.h>
6428:
6429: int main(int argc, char **argv, char **envp)
6430: {
6431: freem_ref_t ref;
6432:
6433: /* we're killing a global node */
6434: ref.reftype = MREF_RT_GLOBAL;
6435:
6436: /* access global "car" */
6437: strcpy(ref.name, "car");
6438:
6439: /* set up the subscripts */
6440: ref.subscript_count = 0;
6441:
6442: /* use the USER namespace */
6443: freem_init("USER");
6444:
6445: /* kill the global and all its descendant subscripts */
6446: freem_kill(&ref);
6447: }
6448: @end verbatim
6449:
6450: @section freem_data()
6451: @cindex libfreem, freem_data()
6452:
6453: @section freem_order()
6454: @cindex libfreem, freem_order()
6455:
6456: @section freem_query()
6457: @cindex libfreem, freem_query()
6458:
6459: @section freem_lock()
6460: @cindex libfreem, freem_lock()
6461:
6462: @section freem_unlock()
6463: @cindex libfreem, freem_unlock()
6464:
6465: @section freem_tstart()
6466: @cindex libfreem, freem_tstart()
6467:
6468: @section freem_trestart()
6469: @cindex libfreem, freem_trestart()
6470:
6471: @section freem_trollback()
6472: @cindex libfreem, freem_trollback()
6473:
6474: @section freem_tlevel()
6475: @cindex libfreem, freem_tlevel()
6476:
6477: @section freem_tcommit()
6478: @cindex libfreem, freem_tcommit()
6479:
6480: @section freem_function()
6481: @cindex libfreem, freem_function()
6482:
6483: @section freem_procedure()
6484: @cindex libfreem, freem_procedure()
6485:
6486: @node FreeM Administrator
6487: @appendix FreeM Administrator
6488: @cindex utilities, system management
6489: @cindex utilities, fmadm
6490: @cindex fmadm
6491:
6492: The @code{fmadm} utility is the preferred method of managing a FreeM installation, and will eventually replace all of the existing utilities.
1.53 snw 6493: In support of FreeM operators, @code{fmadm} presents a consistent, simple interface for all FreeM management tasks, and is namespace-aware.
6494: This appendix will document each @code{fmadm} facility as it is implemented.
1.1 snw 6495:
6496: The @code{fmadm} utility's functions all follow the below, consistent syntax:
6497:
6498: @example
6499: usage: fmadm <action> <object> <namespace> [OPTIONS]
6500: @end example
6501:
6502: The @emph{action} keyword can be one of the following:
6503:
6504: @table @emph
6505:
6506: @item list
6507: Lists instances of @emph{object}
6508:
6509: @item examine
6510: Examines a single instance of @emph{object}
6511:
6512: @item verify
6513: Verifies the integrity of @emph{object}
6514:
6515: @item compact
6516: Compacts @emph{object}
6517:
6518: @item repair
6519: Repairs integrity problems in @emph{object}
6520:
6521: @item create
6522: Creates an instance of @emph{object}
6523:
6524: @item remove
6525: Removes an instance of @emph{object}
6526:
6527: @item import
6528: Imports an @emph{object}
6529:
6530: @item export
6531: Exports an @emph{object}
6532:
6533: @item backup
6534: Creates a backup of @emph{object}
6535:
6536: @item restore
6537: Restores a backup of @emph{object}
6538:
6539: @item migrate
6540: Migrates an instance of @emph{object} from an older FreeM version to the current version
6541:
6542: @item edit
6543: Edits an instance of @emph{object}
6544:
6545: @end table
6546:
6547: The @emph{object} keyword can be one of the following:
6548:
6549: @table @emph
6550:
6551: @item lock
6552: The FreeM @code{LOCK} table.
6553:
6554: Supported actions are @code{list} and @code{remove}.
6555:
6556: @item journal
6557: FreeM after-image journaling.
6558:
6559: Supported actions are @code{examine} and @code{restore}.
6560:
6561: The @code{examine} action will dump the after-image journal entries for the selected namespace in human-readable format.
6562:
6563: The @code{restore} action will play after-image journals forward for the selected namespace.
6564:
6565: @item namespace
6566: FreeM namespaces (collections of M routines and globals).
6567:
6568: No actions yet implemented.
6569:
6570: @item global
6571: The data files representing each FreeM @emph{global}.
6572:
6573: Supported actions are @code{list}, @code{examine}, @code{remove}, and @code{verify}.
6574:
6575: @item routine
6576: An M routine, stored as a @code{.m} file.
6577:
6578: Supported actions are @code{list}, @code{examine}, @code{remove}, @code{import}, @code{export}, @code{backup}, and @code{edit}.
6579:
6580: @item job
6581: A UNIX process representing an instance of the FreeM runtime.
6582:
6583: Supported actions are @code{list} and @code{examine}.
6584:
6585: @end table
6586:
6587:
6588: @node FreeM VIEW Commands and Functions
6589: @appendix FreeM VIEW Commands and Functions
6590:
6591: @section VIEW 16: Total Count of Error Messages/View Single Error Message
6592: @cindex VIEW commands/functions, 16, total count of error messages/view single error message
6593:
6594: Unknown semantics
6595:
6596: @section VIEW 17: Intrinsic Z-Commands
6597: @cindex VIEW commands/functions, 17, intrinsic Z-commands
6598:
6599: Allows the user to retrieve or specify the list of intrinsic Z-commands that FreeM will attempt to run internally, allowing intrinsic Z-commands implemented internally to be replaced with M equivalents implemented as %-routines in the @code{SYSTEM} namespace.
6600:
6601: @section VIEW 18: Intrinsic Z-Functions
6602: @cindex VIEW commands/functions, 18, intrinsic Z-functions
6603:
6604: Allows the user to retrieve or specify the list of intrinsic Z-functions that FreeM will attempt to run internally, allowing intrinsic Z-functions implemented internally to be replaced with M equivalents implemented as %-routines in the @code{SYSTEM} namespace.
6605:
6606: @section VIEW 19: Intrinsic Special Variables
6607: @cindex VIEW commands/functions, 19, intrinsic special variables
6608:
6609: Allows the user to retrieve or specify which special variables are implemented internally.
6610:
6611: @section VIEW 20: Break Service Code
6612: @cindex VIEW commands/functions, 20, break service code
6613:
6614: Allows the user to view or specify the code that will be run when a @code{BREAK} is encountered.
6615:
6616: @section VIEW 21: View Size of Last Global
6617: @cindex VIEW commands/functions, 21, view size of last global
6618:
6619: Allows the user to view the size of the last referenced global.
6620:
6621: @section VIEW 22: Count VIEW 22 Aliases
6622: @cindex VIEW commands/functions, 22, count VIEW 22 aliases
6623:
6624: Retrieves the number of VIEW 22 aliases in effect.
6625:
6626: @section VIEW 23: View Contents of Input Buffer
6627: @cindex VIEW commands/functions, 23, input buffer contents
6628:
6629: Retrieves the contents of the I/O input buffer.
6630:
6631: @section VIEW 24: Maximum Number of Screen Rows
6632: @cindex VIEW commands/functions, 24, maximum number of screen rows
6633:
6634: Retrieves the maximum number of screen rows supported in the current FreeM build.
6635:
6636: @section VIEW 25: Maximum Number of Screen Columns
6637: @cindex VIEW commands/functions, 25, maximum number of screen columns
6638:
6639: Retrieves the maximum number of screen columns supported in the current FreeM build.
6640:
6641: @section VIEW 26: DO/FOR/XECUTE Stack Pointer
6642: @cindex VIEW commands/functions, 26, DO/FOR/XECUTE stack pointer
6643:
6644: Retrieves the @code{DO}, @code{FOR}, and @code{XECUTE} stack pointer.
6645:
6646: @section VIEW 27: DO/FOR/XECUTE Stack Pointer (On Error)
6647: @cindex VIEW commands/functions, 27, DO/FOR/XECUTE stack pointer, on error
6648:
6649: Retrieves the @code{DO}, @code{FOR}, and @code{XECUTE} stack pointer (on error).
6650:
6651: @section VIEW 29: Copy Symbol Table
6652: @cindex VIEW commands/functions, 29, copy symbol table
6653:
6654: Copies the symbol table? We aren't currently aware of what this means.
6655:
6656: @section VIEW 30: Inspect Arguments
6657: @cindex VIEW commands/functions, 30, inspect arguments
6658:
6659: Retrieves the arguments passed to the @code{freem} executable.
6660:
6661: @section VIEW 31: Count Environment Variables
6662: @cindex VIEW commands/functions, 31, count environment variables
6663:
6664: Allows the user to inspect the number of variables in the process environment table.
6665:
6666: @emph{Syntax}
6667:
6668: @example
6669: WRITE $VIEW(31),!
6670: @end example
6671:
6672: @node Implementation Limits
6673: @appendix Implementation Limits
6674:
6675: @cindex limitations, memory
6676: @cindex maximum size, routine
6677: @cindex maximum size, global
6678: @cindex maximum size, string
6679:
6680: @node US-ASCII Character Set
6681: @appendix US-ASCII Character Set
6682:
6683: @multitable {Code} {Character}
6684: @item Code @tab Character
6685: @item 000 @tab @code{<NUL>}
6686: @item 001 @tab @code{<SOH>}
6687: @item 002 @tab @code{<STX>}
6688: @item 003 @tab @code{<ETX>}
6689: @item 004 @tab @code{<EOT>}
6690: @item 005 @tab @code{<ENQ>}
6691: @item 006 @tab @code{<ACK>}
6692: @item 007 @tab @code{<BEL>}
6693: @item 008 @tab @code{<BS>}
6694: @item 009 @tab @code{<HT>}
6695: @item 010 @tab @code{<LF>}
6696: @item 011 @tab @code{<VT>}
6697: @item 012 @tab @code{<FF>}
6698: @item 013 @tab @code{<CR>}
6699: @item 014 @tab @code{<SO>}
6700: @item 015 @tab @code{<SI>}
6701: @item 016 @tab @code{<DLE>}
6702: @item 017 @tab @code{<DC1>}
6703: @item 018 @tab @code{<DC2>}
6704: @item 019 @tab @code{<DC3>}
6705: @item 020 @tab @code{<DC4>}
6706: @item 021 @tab @code{<NAK>}
6707: @item 022 @tab @code{<SYN>}
6708: @item 023 @tab @code{<ETB>}
6709: @item 024 @tab @code{<CAN>}
6710: @item 025 @tab @code{<EM>}
6711: @item 026 @tab @code{<SUB>}
6712: @item 027 @tab @code{<ESC>}
6713: @item 028 @tab @code{<FS>}
6714: @item 029 @tab @code{<GS>}
6715: @item 030 @tab @code{<RS>}
6716: @item 031 @tab @code{<US>}
6717: @item 032 @tab @code{<space>}
6718: @item 033 @tab !
6719: @item 034 @tab ``
6720: @item 035 @tab #
6721:
6722:
6723: @end multitable
6724:
6725: @node FreeM Project Coding Standards
6726: @appendix FreeM Project Coding Standards
6727:
6728: @section Module Headers
6729: @cindex coding standards, module headers
6730:
1.4 snw 6731: Module headers should adhere to the following format (where @code{Dollar} should be replaced with a dollar sign):
1.1 snw 6732:
6733: @verbatim
6734: /*
1.4 snw 6735: * DollarIdDollar
1.1 snw 6736: * Function prototypes, structs, and macros for FreeM
6737: * binding library
6738: *
6739: *
1.28 snw 6740: * Author: Serena Willis <snw@coherent-logic.com>
1.1 snw 6741: * Copyright (C) 1998 MUG Deutschland
1.4 snw 6742: * Copyright (C) <Year> Coherent Logic Development LLC
6743: *
6744: * This file is part of FreeM.
6745: *
6746: * FreeM is free software: you can redistribute it and/or modify
6747: * it under the terms of the GNU Affero Public License as published by
6748: * the Free Software Foundation, either version 3 of the License, or
6749: * (at your option) any later version.
6750: *
6751: * FreeM is distributed in the hope that it will be useful,
6752: * but WITHOUT ANY WARRANTY; without even the implied warranty of
6753: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
6754: * GNU Affero Public License for more details.
6755: *
6756: * You should have received a copy of the GNU Affero Public License
6757: * along with FreeM. If not, see <https://www.gnu.org/licenses/>.
6758: *
6759: * DollarLogDollar
1.1 snw 6760: *
1.4 snw 6761: * SPDX-FileCopyrightText: (C) 2025 Coherent Logic Development LLC
6762: * SPDX-License-Identifier: AGPL-3.0-or-later
1.1 snw 6763: **/
6764: @end verbatim
6765:
6766: @section Variable Naming
6767: @cindex coding standards, variable naming
6768:
6769: Variables should be named in all lowercase letters, and words within them delimited by underscores, such as @code{my_useful_variable}. @code{PascalCase} and @code{camelCase} are not to be used in this codebase under any circumstances.
6770:
6771: Constants defined via the C preprocessor should be in all uppercase letters, with words within them likewise delimited by underscores, such as:
6772:
6773: @verbatim
6774: #define MY_USEFUL_CONSTANT 1
6775: @end verbatim
6776:
6777: @section Indentation and General Layout
6778: @cindex coding standards, indentation
6779: @cindex coding standards, layout
6780:
6781: This project uses four spaces for indentation. Tabs are not to be used under any circumstances, and all source files must use a linefeed character to delineate lines. If you are working on a Windows machine, you must take care to follow this, as Windows will use a carriage return followed by a linefeed by default.
6782:
6783: This project follows a modified version of what is known as the Stroustrup indentation style.
6784:
6785: @section Brace Placement (Functions)
6786: @cindex coding standards, brace placement, functions
6787:
6788: We use modern, ANSI-style function prototypes, with the type specifier on the same line as the function name. You may encounter other styles in the code, but we are transitioning to the new style as time permits.
6789:
6790: Below is a correct example:
6791:
6792: @verbatim
6793: int main(int argc, char **argv, char **envp)
6794: {
6795:
6796: }
6797: @end verbatim
6798:
6799: @section Brace Placement (if-for-while-do)
6800: @cindex coding standards, brace placement, if-for-while-do
6801:
6802: The @code{if} keyword should be followed by one space, then the opening paren and conditional expression. We also use Stroustrup-style @code{else} blocks, rather than the K&R 'cuddled' @code{else}:
6803:
6804: @verbatim
6805: if (x) {
6806: ...
6807: }
6808: else {
6809: ...
6810: }
6811:
6812: while (1) {
6813: ...
6814: }
6815:
6816: for (i = 1; i < 10; i++) {
6817: ...
6818: }
6819:
6820: do {
6821: ...
6822: } while (x);
6823: @end verbatim
6824:
6825: Single-statement if blocks should be isolated to a single line:
6826:
6827: @verbatim
6828: if (x) stmt();
6829: @end verbatim
6830:
6831: not:
6832:
6833: @verbatim
6834: if (x)
6835: stmt ();
6836: @end verbatim
6837:
6838: Notice that there is a space between @code{if} and @code{(x)}, and also between @code{stmt} and @code{()}. This should be followed throughout the code.
6839:
6840: If an @code{if} block has an @code{else if} or @code{else}, all parts of the construct must be bracketed, even if one or more of them contain only one statement:
6841:
6842: @verbatim
6843: if (x) {
6844: foo();
6845: }
6846: else if (y) {
6847: bar();
6848: }
6849: else {
6850: bas();
6851: }
6852: @end verbatim
6853:
6854: @section Labels and goto
6855: @cindex coding standards, labels
6856: @cindex coding standards, goto
6857:
6858: Labels must begin in column 1, and have two lines of vertical space above and one beneath.
6859:
6860: @section Preprocessor Conditionals
6861: @section coding standards, preprocessor conditionals
6862:
6863: I have struggled with this, but have settled upon the standard practice of keeping them in column 1.
6864:
6865: @section Overall Program Spacing
6866: @cindex coding standards, spacing of programs
6867:
6868: @itemize @bullet
6869: @item
6870: Variable declarations fall immediately beneath the opening curly brace, and should initialize the variable right there whenever initialization is used.
6871:
6872: @item
6873: One line between the last variable declaration and the first line of real code.
6874:
6875: @item
6876: The @code{return} statement of a function (when used as the last line of a function) should have one blank line above it and none below it.
6877:
6878: @item
6879: Really long functions (those whose entire body is longer than 24 lines) should have a comment immediately following the closing curly brace of the function, telling you what function the closing brace terminates.
6880: @end itemize
6881:
6882: @section The switch() Statement
6883: @cindex coding standards, switch()
6884:
6885: We indent @code{case} one level beneath @code{switch()}, and the code within each @code{case} beneath the @code{case}. Each @code{case} should have one line of vertical whitespace above it:
6886:
6887: @verbatim
6888: switch(foo) {
6889:
6890: case some_const:
6891: foo();
6892:
6893: break;
6894:
6895: case some_other_const:
6896: bar();
6897:
6898: break;
6899:
6900: default:
6901: exit(1);
6902:
6903: break;
6904: }
6905: @end verbatim
6906:
6907: @section Comments
6908: @cindex coding standards, comments
6909:
6910: We use C-style comments (@code{/* comment */}) exclusively, even on single-line comments. C++ comments (@code{// comment}) are not permitted.
6911:
6912: @node Index
6913: @unnumbered Index
6914:
6915: @printindex cp
6916:
6917: @bye
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