Annotation of freem/doc/freem.texi, revision 1.43
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2: @paragraphindent 0
3: @setfilename freem.info
4: @settitle The FreeM Manual
5:
6: @copying
1.36 snw 7: This manual is for FreeM, (version 0.64.0-rc1), which is a free software@footnote{FreeM subscribes to the software licensing philosophy described in @emph{Free Software, Free Society:
8: Selected Essays of Richard M. Stallman}.} implementation of the M programming language.
1.1 snw 9:
1.39 snw 10: Print-optimized versions of this book are typeset in @emph{Computer Modern} by the author using the @emph{GNU Texinfo} tools.
1.1 snw 11:
1.5 snw 12: Copyright @copyright{} 2014-2025 Coherent Logic Development LLC
1.1 snw 13:
14: @quotation
15: 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.
16: @end quotation
17: @end copying
18:
19: @titlepage
20:
21: @title The FreeM Manual
22: @subtitle @sc{The Official Manual of FreeM}
1.32 snw 23: @subtitle Version 0.64.0-rc1
1.1 snw 24: @c@vskip 10pt
25: @c@center @image{freem-logo-sm,,,,.png}
26: @author Serena Willis
27: @page
28: @vskip 0pt plus 1filll
29: @insertcopying
30: @end titlepage
31: @contents
32:
33: @ifnottex
34: @node Top
35: @top The FreeM Manual
36:
37: This is the official manual for the FreeM programming language.
38: @end ifnottex
39:
40: @dircategory The FreeM Manual
41: @direntry
42: * FreeM: (freem). The FreeM M programming language.
43: @end direntry
44:
45: @menu
46: * Introduction:: About the FreeM Project, its history, and its goals.
1.36 snw 47: * Document Conventions:: Conventions used in this manual.
1.39 snw 48: * A Note on Standards:: FreeM positioning regarding the M Development Committee.
1.1 snw 49: * FreeM Invocation:: How to invoke FreeM from the command line.
1.22 snw 50: * The FreeM Environment Daemon:: Managing shared resources in the FreeM environment.
1.1 snw 51: * The FreeM Direct-Mode Environment:: Executing M programs interactively.
1.36 snw 52: * Debugging:: The program development cycle of FreeM.
1.1 snw 53:
54: * Directives:: Per-Routine Language Directives.
55: * Intrinsic Special Variables:: Intrinsic Special Variables.
56: * Intrinsic Functions:: Intrinsic Functions.
57: * OBJECT Methods:: Methods for OBJECT variables.
58: * STRING Methods:: Methods for STRING variables.
59: * Commands:: Commands.
60: * Structured System Variables:: Structured System Variables.
61: * Operators:: FreeM Operators.
62:
63: * Routines:: The units of M code in FreeM.
64: * Types:: FreeM data types.
65: * Globals:: FreeM persistent sparse arrays.
66: * Concurrency Control:: @code{LOCK}ing and transaction processing.
67: * Local Variables:: In-memory variables.
68: * Scoping:: Scoping in FreeM.
69: * Decision Constructs:: @code{IF}, @code{THEN}, @code{ELSE}, @code{$SELECT}, and postconditionals.
70: * Branch Constructs:: Labels, @code{GOTO}, @code{DO}, and @code{JOB}.
71: * Loop Constructs:: The @code{FOR} loop.
72: * Modular Programming:: Extrinsic functions and subroutines.
73: * Object-Oriented Programming:: Classes and objects in FreeM.
74: * Libraries:: System and user libraries.
75: * Sequential I/O:: Processing sequential files in FreeM.
76: * Network I/O:: Handling network sockets in FreeM.
77: * Extended Global References:: Accessing globals in non-default namespaces.
78: * Global Aliasing:: Defining alternate names for globals.
79: * Global Mappings:: Mapping global names to non-default namespaces.
80:
81: * Asynchronous Event Handling:: Handling asynchronous events in FreeM.
82: * Global Triggers:: Responding to global accesses in M code.
83: * Synchronous Event Handling:: Synchronous events in FreeM.
84:
85:
86: * GUI Programming with MWAPI:: Creating graphical interfaces in FreeM.
87:
88: * User-Defined Z Commands:: Adding your own Z commands to FreeM.
89: * User-Defined Z Functions:: Adding your own Z functions to FreeM.
90: * User-Defined SSVNs:: Adding your own SSVNs to FreeM.
91:
92: * Language Dialects:: Controlling FreeM standards compliance.
93:
94: * System Library Routines:: FreeM built-in library of M routines.
95:
96: * Interrupt Handling:: How FreeM handles interrupts.
97: * Error Processing:: How to handle errors in M program code.
98: * FreeM Error Codes:: Explanations of each FreeM error code.
99:
100: * System Configuration:: Configuring your FreeM installation.
101: * Accessing FreeM from C Programs:: How to use the mlib interface.
102:
103: * FreeM Administrator:: The fmadm system manager tool.
104: * FreeM Legacy Utilities:: FreeM legacy system manager utilities.
105: * FreeM VIEW Commands and Functions:: Getting and setting info about FreeM internals.
106: * Implementation Limits:: FreeM limitations.
107: * US-ASCII Character Set:: The US-ASCII character set.
108: * FreeM Project Coding Standards:: How to write code for submission to the FreeM project.
109:
110: * Index:: Complete index.
111: @end menu
112:
113: @node Introduction
114: @unnumbered Introduction
115:
1.36 snw 116: 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 117:
118: 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.
119:
1.36 snw 120: 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 121:
1.39 snw 122: For more information on FreeM history, see @code{@emph{$PREFIX}/share/freem/doc/freem_history.*} (distributed in PostScript, PDF, and plain text formats).
123:
1.1 snw 124: @section Production Readiness
125:
126: FreeM is not yet production-ready. There are several show-stopping bugs that preclude a general release for public use:
127:
128: @itemize @bullet
129:
130: @item
131: @code{@ref{VIEW}} commands and @code{@ref{$VIEW()}} functions are used extensively to configure and inspect the run-time behavior of FreeM, rather than the "canonical" SSVN-based approach.
132:
133: @item
134: Server sockets are not yet implemented.
135:
136: @item
137: There are some situations that can result in segmentation faults and/or lock-ups.
138:
139: @item
140: In spite of our best efforts, this manual is not yet complete.
141:
142: @end itemize
143:
144: @section Contributors
145: Current contributors denoted with a @emph{+} following their name and role.
146: @cindex contributors, ha-Ashkenaz, Shalom
147: @cindex contributors, Best, John
148: @cindex contributors, Diamond, Jon
149: @cindex contributors, Fox, Ronald L.
150: @cindex contributors, Gerum, Winfried
151: @cindex contributors, Kreis, Greg
152: @cindex contributors, Landis, Larry
153: @cindex contributors, Milligan, Lloyd
154: @cindex contributors, Morris, Steve
155: @cindex contributors, Murray, John
156: @cindex contributors, Pastoors, Wilhelm
157: @cindex contributors, Schell, Kate
158: @cindex contributors, Schofield, Lyle
159: @cindex contributors, Stefanik, Jim
160: @cindex contributors, Trocha, Axel
161: @cindex contributors, Walters, Dick
162: @cindex contributors, Whitten, David
163: @cindex contributors, Wicksell, David
164: @cindex contributors, Willis, Serena
165: @cindex contributors, Zeck, Steve
166:
167: @itemize @bullet
168:
169: @item
170: Shalom ha-Ashkenaz (Original Implementer)
171:
172: @item
173: John Best (IBM i and OS/400)
174:
175: @item
176: Jon Diamond (Library, Utilities, Conformance)
177:
178: @item
179: Ronald L. Fox (Initial port to Red Hat 5/libc-6)
180:
181: @item
182: Winfried Gerum (Code, Advice, MTA coordination)
183:
184: @item
185: Greg Kreis (Hardhats coordination, Dependencies)
186:
187: @item
188: Larry Landis (Coordination, Code, Documentation)
189:
190: @item
191: Rick Marshall (Testing, MDC Conformance) @emph{+}
192:
193: @item
194: Lloyd Milligan (Code, Testing, Documentation)
195:
196: @item
197: Steve Morris (Code, Microsoft)
198:
199: @item
200: John Murray (Code, Conformance)
201:
202: @item
203: Wilhelm Pastoors (Testing, Documentation)
204:
205: @item
206: Kate Schell (Coordination, Conformance, MTA, MDC, Advice)
207:
208: @item
209: Lyle Schofield (Advice, Prioritization, Tracking, Project Management)
210:
211: @item
212: Jim Stefanik (GNU/Linux on s390x, IBM AIX, IBM z/OS)
213:
214: @item
215: Axel Trocha (Code, Utilities)
216:
217: @item
218: Dick Walters (Project Lead, Chief Coordinator, MTA)
219:
220: @item
221: David Whitten (QA Test Suite, MDC, Advice) @emph{+}
222:
223: @item
224: David Wicksell (Debugging, Code, Testing) @emph{+}
225:
226: @item
227: Serena Willis (Current Maintainer and Project Lead) @emph{+}
228:
229: @item
230: Steve Zeck (Code)
231:
232: @end itemize
1.36 snw 233:
234: @node Document Conventions
235: @chapter Document Conventions
236: @cindex document conventions
237: @cindex conventions
238:
239: @section Formatting Conventions
240:
241: This manual uses the following formatting conventions:
242: @itemize
243: @item Code examples, filesystem paths, and commands are presented in @code{monospace}
244: @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
245: @item New terminology is introduced in @emph{proportional italics}
246: @end itemize
247:
248: @section Definitions
249:
250: FreeM uses abbreviations for common language elements:
251:
252: @table @asis
253: @item @emph{$PREFIX}
254: Refers to the base filesystem location within which FreeM is installed. For most distribution methods of FreeM, @emph{$PREFIX} represents either @code{/} or @code{/usr/local}.
1.37 snw 255: @item @emph{dlabel}
256: 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}.
257: @item @emph{entryref}
258: Refers to an M routine entry point, denoted in the format @code{@emph{dlabel} [+@emph{intexpr}][^@emph{routine}]}.
1.36 snw 259: @item @emph{expr}
260: 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}.
261: @item @emph{glvn}
262: Refers to the name of an M global, local, or structured system variable.
263: @item @emph{gvn}
264: Refers to the name of an M global variable.
265: @item @emph{intexpr}
266: Refers to an integer expression.
1.37 snw 267: @item @emph{intlit}
268: Refers to an integer literal.
1.36 snw 269: @item @emph{ISV}, @emph{isv}
270: Refers to an M intrinsic special variable; @code{$JOB} and @code{$IO} are examples of ISVs.
271: @item @emph{L}
272: Indicates a @emph{list} of the following item, e.g., @emph{L gvn} means @emph{list of global variable names}.
273: @item @emph{lvn}
274: Refers to the name of an M local variable.
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}
280: Refers to a truth-valued expression.
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
1.32 snw 443: Coherent Logic Development FreeM version 0.64.0-rc1 (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.
1117: * $ZNEXT():: Unknown.
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.
1315:
1.1 snw 1316: @node $ORDER()
1317: @section $ORDER
1318: @cindex $ORDER
1319: @cindex intrinsic functions, $ORDER
1320:
1.25 snw 1321: Returns the previous subscript or next subscript in a local, global, or a subset of structured system variables.
1322:
1323: The first argument is the subscripted local, global, or SSVN.
1324:
1325: The optional second argument can be @code{1} to retrieve the next subscript, or @code{-1} to return the previous.
1326:
1.1 snw 1327: @node $PIECE()
1328: @section $PIECE
1329: @cindex $PIECE
1330: @cindex intrinsic functions, $PIECE
1331:
1332: @emph{Syntax}
1333:
1334: @code{$PIECE(@emph{s},@emph{d}[,@emph{n}[,@emph{end}]])}
1335:
1336: Accesses the @code{n}th through @code{end} @code{d}-delimited pieces of string @code{s}.
1337:
1338: The first argument is the string to be evaluated.
1339:
1340: The second argument is the delimiter to be used.
1341:
1342: The optional third argument is the first @code{d}-delimited piece to access, and defaults to @code{1}.
1343:
1344: The optional fourth argument is the final @code{d}-delimited piece to access, and defaults to the value of the third argument (@code{n}).
1345:
1346: 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:
1347:
1348: @example
1.28 snw 1349: ; ^snw="this^is^a^piece"
1350: SET $PIECE(^snw,"^",2)="isn't" ; => "this^isn't^a^piece"
1.1 snw 1351: @end example
1352:
1353: @node $QLENGTH()
1354: @section $QLENGTH
1355: @cindex $QLENGTH
1356: @cindex intrinsic functions, $QLENGTH
1357:
1358: @emph{Syntax}
1359:
1360: @example
1361: @code{$QLENGTH(@emph{expr V glvn})}
1362: @end example
1363:
1364: Returns the number of subscripts in @emph{glvn}.
1365:
1366: @emph{Example}
1367: @example
1368: @code{SET SUBCT=$QLENGTH("^GBL(1,2,3)") ; => 3}
1369: @end example
1370:
1371: @node $QSUBSCRIPT()
1372: @section $QSUBSCRIPT
1373: @cindex $QSUBSCRIPT
1374: @cindex intrinsic functions, $QSUBSCRIPT
1375:
1376: @emph{Syntax}
1377:
1378: @example
1379: @code{$QSUBSCRIPT(@emph{expr V glvn},@emph{expr V n})}
1380: @end example
1381:
1.28 snw 1382: In the RHS form, returns the @emph{n}th subscript of @emph{glvn}.
1.1 snw 1383:
1384: @emph{Example}
1385:
1386: @example
1387: @code{SET SUB=$QSUBSCRIPT("^GBL(1,2,3)",2) ; => 2}
1388: @end example
1389:
1.28 snw 1390: @emph{Syntax}
1391:
1392: @example
1393: @code{SET $QSUBSCRIPT(@emph{expr V glvn},@emph{expr V n})=@emph{expr} ; => ^GBL(1,4,3)}
1394: @end example
1395:
1396: In the LHS form, sets the @emph{n}th subscript of @emph{glvn} to @emph{expr}.
1397:
1.1 snw 1398: @node $QUERY()
1399: @section $QUERY
1400: @cindex $QUERY
1401: @cindex intrinsic functions, $QUERY
1402:
1403: Returns the next subscripted reference in a global.
1404:
1405: @emph{Syntax}
1406:
1407: @example
1408: @code{$QUERY(@emph{glvn})}
1409: @end example
1410:
1411: @emph{Example}
1412:
1413: We will assume the following data structure exists:
1414: @example
1.28 snw 1415: ^snw(1)=1
1416: ^snw(1,2)="foo"
1417: ^snw(2)=3
1418: ^snw(3)=""
1.1 snw 1419: @end example
1420:
1.28 snw 1421: The following code will retrieve the next subscripted name after @code{^snw(1)}:
1.1 snw 1422:
1423: @example
1.28 snw 1424: @code{SET NEXTNAM=$QUERY(^snw(1)) ; => ^snw(1,2)}
1.1 snw 1425: @end example
1426:
1427: @node $RANDOM()
1428: @section $RANDOM
1429: @cindex $RANDOM
1430: @cindex intrinsic functions, $RANDOM
1431:
1432: @emph{Syntax}
1433:
1434: @example
1435: $RANDOM(@emph{max})
1436: @end example
1437:
1438: Returns a pseudo-random integer in the range of @code{0..@emph{max} - 1}
1439:
1440: @node $REVERSE()
1441: @section $REVERSE
1442: @cindex $REVERSE
1443: @cindex intrinsic functions, $REVERSE
1444:
1445: @emph{Syntax}
1446:
1447: @example
1448: $REVERSE(@emph{s})
1449: @end example
1450:
1451: Returns the reverse of string @emph{s}.
1452:
1453: @emph{Example}
1454:
1455: @example
1456: SET FOO=$REVERSE("ABC") ; => CBA
1457: @end example
1458:
1459: @node $SELECT()
1460: @section $SELECT
1461: @cindex $SELECT
1462: @cindex intrinsic functions, $SELECT
1463:
1464: 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.
1465:
1466: @emph{Example}
1467:
1468: @example
1469: SET FOO=$SELECT(1=2:"math is broken",1=1:"the world makes sense") ; => "the world makes sense"
1470: @end example
1471:
1472: @node $STACK()
1473: @section $STACK
1474: @cindex $STACK
1475: @cindex intrinsic functions, $STACK
1476:
1477: Returns information about the program execution stack. The @code{$STACK} intrinsic function has both a one-argument form and a two-argument form.
1478:
1479: @emph{Syntax (One-Argument)}
1480:
1481: @example
1482: $STACK(@emph{<num>})
1483: @end example
1484:
1485: If @emph{num} is @code{0}, returns the command with which this FreeM instance was invoked.
1486:
1487: If @emph{num} is @code{-1}, returns the current program execution stack level.
1488:
1489: 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:
1490:
1491: @table @asis
1492:
1493: @item @code{$$}
1494: If @code{$STACK(@emph{<num>})="$$"}, program execution stack level @code{num} was created as the result of an extrinsic function call
1495:
1496: @item @emph{<m-command>}
1497: 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.
1498:
1499: @end table
1500:
1501: @emph{Syntax (Two-Argument})
1502:
1503: @example
1504: $STACK(@emph{<num>},"[ECODE|MCODE|PLACE]")
1505: @end example
1506:
1507: Returns the error codes, M program code, or entryref applicable to the action that created program execution stack level @emph{num}.
1508:
1509: @node $TEXT()
1510: @section $TEXT
1511: @cindex $TEXT
1512: @cindex intrinsic functions, $TEXT
1513:
1514: Returns a line of code from a routine.
1515:
1516: @node $TRANSLATE()
1517: @section $TRANSLATE
1518: @cindex $TRANSLATE
1519: @cindex intrinsic functions, $TRANSLATE
1520:
1.25 snw 1521: Replaces characters in a string.
1522:
1523: The first argument is a string expression representing the text to be changed.
1524:
1525: The second argument is a list of characters to replace.
1526:
1527: The third argument is a list of characters to use as the replacements for the characters in the second argument.
1528:
1529: @emph{Example}
1530:
1531: @example
1532: DEFAULT.USER> W $TRANSLATE("twig","wt","rb")
1533: brig
1534: @end example
1535:
1.1 snw 1536: @node $TYPE()
1537: @section $TYPE
1538: @cindex $TYPE
1539: @cindex intrinsic functions, $TYPE
1540: @cindex object functions, $TYPE
1541:
1542: Returns a string giving the class of the object specified in the parameter.
1543:
1544: @xref{Object-Oriented Programming}
1545:
1546: @node $VIEW()
1547: @section $VIEW
1548: @cindex $VIEW
1549: @cindex intrinsic functions, $VIEW
1550:
1551: @node $ZBOOLEAN()
1552: @section $ZBOOLEAN
1553: @cindex $ZBOOLEAN
1554: @cindex intrinsic functions, $ZBOOLEAN
1555: @cindex intrinsic functions, implementation-specific
1556:
1557:
1558: Performs @emph{boolean-operation} on numeric arguments @emph{A} and @emph{B}.
1559:
1560: @emph{Syntax}
1561:
1562: @example
1563: SET RESULT=$ZBOOLEAN(@emph{A},@emph{B},@emph{boolean-operation})
1564: @end example
1565:
1566: @code{$ZBOOLEAN} Operations (@emph{boolean-operation} values)
1567:
1568: @table @code
1569: @item 0
1570: Always @emph{false}
1571: @item 1
1572: @code{A AND B}
1573: @item 2
1574: @code{A AND NOT B}
1575: @item 3
1576: @code{A}
1577: @item 4
1578: @code{NOT A AND B}
1579: @item 5
1580: @code{B}
1581: @item 6
1582: @code{A XOR B}
1583: @item 7
1584: @code{A OR B}
1585: @item 8
1586: @code{A NOR B}
1587: @item 9
1588: @code{A EQUALS B}
1589: @item 10
1590: @code{NOT B}
1591: @item 11
1592: @code{A OR NOT B}
1593: @item 12
1594: @code{NOT A}
1595: @item 13
1596: @code{NOT A OR B}
1597: @item 14
1598: @code{A NAND B}
1599: @item 15
1600: Always @emph{true}
1601: @end table
1602:
1603: @node $ZCALL()
1604: @section $ZCALL
1605: @cindex $ZCALL
1606: @cindex intrinsic functions, $ZCALL
1607: @cindex intrinsic functions, implementation-specific
1608:
1.26 snw 1609: Purpose unknown.
1610:
1.1 snw 1611: @node $ZCRC()
1612: @section $ZCRC
1613: @cindex $ZCRC
1614: @cindex intrinsic functions, $ZCRC
1615: @cindex intrinsic functions, implementation-specific
1616:
1617: Returns a checksum of @code{arg1}.
1618:
1619: @emph{Syntax}
1620:
1621: @code{$ZCRC(@emph{arg1})}
1622:
1623: @code{SET VAR=$ZCRC("MUMPS") ; => 86}
1624:
1625: @node $ZDATA()
1626: @section $ZDATA
1627: @cindex $ZDATA
1628: @cindex intrinsic functions, $ZDATA
1629: @cindex intrinsic functions, implementation-specific
1630:
1.26 snw 1631: Purpose unknown.
1632:
1.1 snw 1633: @node $ZDATE()
1634: @section $ZDATE
1635: @cindex $ZDATE
1636: @cindex intrinsic functions, $ZDATE
1637: @cindex intrinsic functions, implementation-specific
1638:
1639: Converts a @code{@ref{$HOROLOG}} string into a human-readable date.
1640:
1641: @emph{Syntax}
1642:
1643: @example
1644: SET VAR=$ZDATE($H[,@emph{<format-string>}])
1645: @end example
1646:
1647: 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}).
1648:
1649: @xref{^$SYSTEM}
1650:
1651: @node $ZEDIT()
1652: @section $ZEDIT
1653: @cindex $ZEDIT
1654: @cindex intrinsic functions, $ZEDIT
1655: @cindex intrinsic functions, implementation-specific
1656:
1.26 snw 1657: Purpose unknown.
1658:
1.1 snw 1659: @node $ZHOROLOG()
1660: @section $ZHOROLOG
1661: @cindex $ZHOROLOG
1662: @cindex intrinsic functions, $ZHOROLOG
1663: @cindex intrinsic functions, implementation-specific
1664:
1665: Converts date and/or time values producible by @code{@ref{$ZDATE()}} or @code{@ref{$ZTIME()}} to @code{@ref{$HOROLOG}} format.
1666:
1667: @emph{Syntax}
1668:
1669: @example
1670: $ZHOROLOG(@emph{<date-value>},@emph{<format-string>})
1671: @end example
1672:
1673: @emph{<date-value>} is a date or time string compatible with the formats from @code{@ref{$ZDATE()}} or @code{@ref{$ZTIME}}.
1674:
1675: @emph{<format-string>} is a format string of the same format as used by the @code{strptime(3)} UNIX function.
1676:
1677: @node $ZKEY()
1678: @section $ZKEY
1679: @cindex $ZKEY
1680: @cindex intrinsic functions, $ZKEY
1681: @cindex intrinsic functions, implementation-specific
1682:
1.26 snw 1683: Purpose unknown.
1684:
1.1 snw 1685: @node $ZLENGTH()
1686: @section $ZLENGTH
1687: @cindex $ZLENGTH
1688: @cindex intrinsic functions, $ZLENGTH
1689: @cindex intrinsic functions, implementation-specific
1690:
1.26 snw 1691: Purpose unknown.
1692:
1.1 snw 1693: @node $ZLSD()
1694: @section $ZLSD
1695: @cindex $ZLSD
1696: @cindex intrinsic functions, $ZLSD
1697: @cindex intrinsic functions, implementation-specific
1698:
1699: 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.
1700:
1701: @emph{Syntax}
1702:
1703: @code{SET VAR=$ZLSD(@emph{arg1},@emph{arg2})}
1704:
1705: @emph{Example}
1706:
1707: @code{SET VAR=$ZLSD("KITTENS","MITTENS") ; => 1}
1708:
1709: @node $ZM()
1710: @section $ZM
1711: @cindex $ZM
1712: @cindex intrinsic functions, $ZM
1713: @cindex intrinsic functions, implementation-specific
1714:
1715: @node $ZNAME()
1716: @section $ZNAME
1717: @cindex $ZNAME
1718: @cindex intrinsic functions, $ZNAME
1719: @cindex intrinsic functions, implementation-specific
1720:
1.26 snw 1721: Purpose unknown.
1722:
1.1 snw 1723: @node $ZNEXT()
1724: @section $ZNEXT
1725: @cindex $ZNEXT
1726: @cindex intrinsic functions, $ZNEXT
1727: @cindex intrinsic functions, implementation-specific
1728:
1.26 snw 1729: Purpose unknown.
1730:
1.1 snw 1731: @node $ZORDER()
1732: @section $ZORDER
1733: @cindex $ZORDER
1734: @cindex intrinsic functions, $ZORDER
1735: @cindex intrinsic functions, implementation-specific
1736:
1.26 snw 1737: Purpose unknown.
1738:
1.1 snw 1739: @node $ZPIECE()
1740: @section $ZPIECE
1741: @cindex $ZPIECE
1742: @cindex intrinsic functions, $ZPIECE
1743: @cindex intrinsic functions, implementation-specific
1744:
1.26 snw 1745: Purpose unknown.
1746:
1.1 snw 1747: @node $ZPREVIOUS()
1748: @section $ZPREVIOUS
1749: @cindex $ZPREVIOUS
1750: @cindex intrinsic functions, $ZPREVIOUS
1751: @cindex intrinsic functions, implementation-specific
1752:
1.26 snw 1753: Purpose unknown.
1754:
1.1 snw 1755: @node $ZREPLACE()
1756: @section $ZREPLACE
1757: @cindex $ZREPLACE
1758: @cindex intrinsic functions, $ZREPLACE
1759: @cindex intrinsic functions, implementation-specific
1760:
1761: Replaces all instances of @code{arg2} with @code{arg3} in string @code{arg1}.
1762:
1763: @emph{Syntax}
1764: @code{$ZREPLACE(@emph{arg1},@emph{arg2},@emph{arg3})}
1765:
1766: @emph{Example}
1767:
1768: @code{SET VAR=$ZREPLACE("CAT","C","B") ; => BAT}
1769:
1770: @node $ZSYNTAX()
1771: @section $ZSYNTAX
1772: @cindex $ZSYNTAX
1773: @cindex intrinsic functions, $ZSYNTAX
1774: @cindex intrinsic functions, implementation-specific
1775:
1776: @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.
1777:
1778: @emph{Syntax}
1779: @example
1780: $ZSYNTAX(@emph{expr V mcode})
1781: @end example
1782:
1783: If no syntax error is found, returns the empty string.
1784:
1785: 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.
1786:
1787: @node $ZTIME()
1788: @section $ZTIME
1789: @cindex $ZTIME
1790: @cindex intrinsic functions, $ZTIME
1791: @cindex intrinsic functions, implementation-specific
1792:
1793: Converts a @code{@ref{$HOROLOG}} string into a human-readable time.
1794:
1795: @emph{Syntax}
1796:
1797: @example
1798: SET VAR=$ZTIME($H[,@emph{<format-string>}])
1799: @end example
1800:
1801: 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}).
1802:
1803: @node OBJECT Methods
1804: @chapter OBJECT Methods
1805:
1806: These methods are part of the @code{^%OBJECT} class, from which all FreeM objects ultimately inherit.
1807:
1808: 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.
1809:
1810: @menu
1811: * $$TONUMBER:: Returns the canonical numeric representation of the object.
1812: * $$TYPE:: Returns the fully-qualified class name of the object.
1813: * $$VALUE:: Returns the value of the object.
1814: @end menu
1815:
1816: @node $$TONUMBER
1817: @section $$TONUMBER
1818:
1819: Returns (when applicable) a canonical numeric representation of the referenced object.
1820:
1821: @emph{Syntax}
1822:
1823: @example
1824: W $$MYOBJECT.TONUMBER(),!
1825: @end example
1826:
1827: If no canonical numeric representation of the object is possible, will return the empty string.
1828:
1829: @node $$TYPE
1830: @section $$TYPE
1831:
1832: Returns the fully-qualified class of the referenced object.
1833:
1834: @emph{Syntax}
1835:
1836: @example
1837: W $$MYOBJECT.TYPE()
1838: @end example
1839:
1840: Note that M variables that are created by non-object-oriented means will be objects of the @code{^%STRING} class.
1841:
1842: @node $$VALUE
1843: @section $$VALUE
1844:
1845: Returns the value of the referenced object.
1846:
1847: @emph{Syntax}
1848:
1849: @example
1850: W $$MYOBJECT.VALUE()
1851: @end example
1852:
1853: @node STRING Methods
1854: @chapter STRING Methods
1855:
1856: These are methods inherent to the @code{^%STRING} class, which is the default class for M variables created without specifying a class.
1857:
1858: @menu
1859: * $$ASCII:: Return the ASCII code of a character within the string.
1860: * $$DATA:: Return tree characteristics of the string.
1861: * $$DISTANCE:: Determine Levenstein distance between this string and another.
1862: * $$EXTRACT:: Return a substring of the string.
1863: * $$FIND:: Find the position of a substring within the string.
1864: * $$FNUMBER:: Format numbers.
1865: * $$JUSTIFY:: Pad the string to specific positions.
1866: * $$LENGTH:: Return the length of the string.
1867: * $$PIECECOUNT:: Return the count of pieces existing between instances of a delimiter.
1868: * $$PIECE:: Return a delimited subset of the string.
1869: * $$REPLACE:: Replace instances of a substring within the string.
1870: * $$REVERSE:: Reverse the order of characters in the string.
1871: * $$TOLOWER:: Return a lowercase version of the string.
1872: * $$TOUPPER:: Return an uppercase version of the string.
1873: * $$TRANSLATE:: Replace individual characters within the string.
1874: @end menu
1875:
1876: @node $$ASCII
1877: @section $$ASCII
1878:
1879: Returns the ASCII code of a character within the string. See @ref{$ASCII()}.
1880:
1881: @emph{Syntax}
1882:
1883: @example
1884: W $$MYOBJECT.ASCII(3)
1885: @end example
1886:
1887: The above example returns the ASCII code in position 3 of string object @code{MYOBJECT}.
1888:
1889: @node $$DATA
1890: @section $$DATA
1891:
1892: Returns the value of the @code{$DATA} intrinsic function as performed on the value of the object. See @ref{$DATA()}.
1893:
1894: @emph{Syntax}
1895:
1896: @example
1897: W $$MYOBJECT.DATA()
1898: @end example
1899:
1900: @node $$DISTANCE
1901: @section $$DISTANCE
1902:
1903: Returns the Levenstein distance between the string and another string. See @ref{$ZLSD()}.
1904:
1905: @emph{Syntax}
1906:
1907: @example
1908: W $$MYOBJECT.DISTANCE("someString")
1909: @end example
1910:
1911: @node $$EXTRACT
1912: @section $$EXTRACT
1913:
1914: Returns a substring of the string. See @ref{$EXTRACT()}.
1915:
1916: @emph{Syntax}
1917:
1918: @example
1919: $$<objectName>.EXTRACT(<start>,<end>)
1920: @end example
1921:
1922:
1923: @node $$FIND
1924: @section $$FIND
1925:
1.25 snw 1926: Finds the character immediately following the first occurence of a substring within a string.
1927:
1928: The first argument is the substring to be located.
1929:
1930: The second argument is the position within the string at which to begin searching.
1931:
1932: See @ref{$FIND()}.
1933:
1.1 snw 1934: @node $$FNUMBER
1935: @section $$FNUMBER
1936:
1.25 snw 1937: Formats a number according to a set of formatting codes.
1938:
1939: The argument is a series of formatting codes. See @ref{$FNUMBER()} for details.
1940:
1.1 snw 1941: @node $$JUSTIFY
1942: @section $$JUSTIFY
1943:
1.25 snw 1944: Right-justifies a string based on a specified fixed length.
1945:
1946: The first argument is the character length of the output.
1947:
1948: 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.
1949:
1950: See @ref{$JUSTIFY()} for details.
1951:
1.1 snw 1952: @node $$LENGTH
1953: @section $$LENGTH
1954:
1.25 snw 1955: Returns the length of the string.
1956:
1.1 snw 1957: @node $$PIECECOUNT
1958: @section $$PIECECOUNT
1959:
1.25 snw 1960: Returns the number of items in a list delimited by the character specified in the argument.
1961:
1.1 snw 1962: @node $$PIECE
1963: @section $$PIECE
1964:
1.25 snw 1965: @emph{Syntax}
1966:
1967: @code{$PIECE(@emph{d}[,@emph{n}[,@emph{end}]])}
1968:
1969: Accesses the @code{n}th through @code{end} @code{d}-delimited pieces of the string.
1970:
1971: The first argument is the delimiter to be used.
1972:
1973: The optional second argument is the first @code{d}-delimited piece to access, and defaults to @code{1}.
1974:
1975: The optional third argument is the final @code{d}-delimited piece to access, and defaults to the value of the third argument (@code{n}).
1976:
1977:
1.1 snw 1978: @node $$REPLACE
1979: @section $$REPLACE
1980:
1.25 snw 1981: @emph{Syntax}
1982: @code{myString.$$REPLACE(@emph{arg1},@emph{arg2})}
1983:
1984: Replaces all instances of @code{arg2} with @code{arg3} in @code{myString}.
1985:
1.1 snw 1986: @node $$REVERSE
1987: @section $$REVERSE
1988:
1.25 snw 1989: Returns the reverse of the string.
1990:
1.1 snw 1991: @node $$TOLOWER
1992: @section $$TOLOWER
1993:
1.25 snw 1994: Returns an all-lowercase version of the string.
1995:
1.1 snw 1996: @node $$TOUPPER
1997: @section $$TOUPPER
1998:
1.25 snw 1999: Returns an all-uppercase version of the string.
2000:
1.1 snw 2001: @node $$TRANSLATE
2002: @section $$TRANSLATE
2003:
1.25 snw 2004: Identical to @ref{$TRANSLATE()}, except that the arguments are shifted left by one, and the input string is implicit (the object).
2005:
1.1 snw 2006: @node Commands
2007: @chapter Commands
2008: @cindex commands
2009:
2010: @menu
2011: * @@:: Execute the following expression as M code.
2012: * !:: Run an external program or command.
2013: * !!:: Launch a subshell from FreeM direct mode.
2014: * ABLOCK:: Increment the block counter for one or more event classes.
2015: * ASSERT:: Raise error when a conditional expression evaluates @emph{false}.
2016: * ASTART:: Enable asynchronous event handling for one or more event classes.
2017: * ASTOP:: Disable asynchronous event handling for one or more event classes.
2018: * AUNBLOCK:: Decrement the block counter for one or more event classes.
2019: * BREAK:: Interrupt a running routine to allow interactive debugging.
2020: * CLOSE:: Close an input/output device.
2021: * DO:: Transfer program control to one or more subroutines or introduces a new execution level.
2022: * ELSE:: Execute the remainder of a line if @code{@ref{$TEST}} evaluates @emph{false}.
2023: * FOR:: Repeat execution of a line or block of code.
2024: * GOTO:: Unconditionally transfer program execution to a supplied @emph{entryref}.
2025: * HALT:: Terminate the current FreeM interpreter instance.
2026: * HANG:: Temporarily suspend the running program.
2027: * IF:: Execute the remainder of a line if a conditional expression evaluates @emph{true}.
2028: * JOB:: Execute an @emph{entryref} in a child process.
2029: * KILL:: Remove data from a local, global, or structured system variable.
2030: * KSUBSCRIPTS:: Kill only the descendant subscripts of a local, global, global, or structured system variable.
2031: * KVALUE:: Kill only the value of a local, global, or structured system variable.
2032: * LOCK:: Control advisory locking for concurrency control.
2033: * MERGE:: Merge contents of one local, global, or structured system variable into another.
2034: * NEW:: Introduce a new scope for a specified local variable or intrinsic special variable or instantiate an object.
2035: * OPEN:: Open a sequential or socket input/output device.
2036: * QUIT:: End execution of the current process level, optionally with return value.
2037: * READ:: Read input from an input/output device.
2038: * SET:: Set the value of a local variable, global, intrinsic special variable, or structured system variable.
2039: * TCOMMIT:: Commit a transaction.
2040: * THEN:: Preserve @code{@ref{$TEST}} until the end of the current line.
2041: * TROLLBACK:: Roll back all pending transactions.
2042: * TSTART:: Introduce a new transaction processing level.
2043: * USE:: Set the currently-active input/output device.
2044: * VIEW:: Modify FreeM internal parameters.
2045: * WRITE:: Write output to current input/output device.
2046: * XECUTE:: Interpret string as M code.
2047: * ZBREAK:: Unknown.
1.42 snw 2048: * ZCONST:: Define a constant that cannot be altered after initial definition.
1.1 snw 2049: * ZGO:: Unknown.
2050: * ZHALT:: Unknown.
2051: * ZINSERT:: Insert code into routine buffer.
1.42 snw 2052: * ZJOB:: Invokes a job, ignoring any timeouts.
1.1 snw 2053: * ZLOAD:: Load routine into routine buffer.
1.42 snw 2054: * ZMAP:: Map a global name to a non-default namespace.
1.1 snw 2055: * ZNEW:: Unknown.
2056: * ZPRINT:: Print contents of routine buffer.
1.42 snw 2057: * ZQUIT:: Quits multiple stack levels at once.
1.1 snw 2058: * ZREMOVE:: Remove code from routine buffer.
2059: * ZSAVE:: Save routine buffer to disk.
1.42 snw 2060: * ZTHROW:: Programmatically raise an error condition.
1.1 snw 2061: * ZTRAP:: Unknown.
1.42 snw 2062: * ZUNMAP:: Remove a mapping of a global to a non-default namespace.
2063: * ZWATCH:: Enable or disable watchpoints, or set or clear watchpoints on specified globals, locals, or structured system variables.
2064: * ZWITH:: Set prefix for future variable references.
1.1 snw 2065: * ZWRITE:: Write local variable, global, or structured system variable to @code{@ref{$IO}}.
2066: @end menu
2067:
2068: @node @@
2069: @section @@
2070: @cindex @@
2071: @cindex commands, @@
2072: @cindex commands, implementation-specific
2073: @cindex commands, non-standard
2074:
2075: Executes FreeM code @emph{expr V mcode}.
2076:
2077: @emph{Syntax}
2078:
2079: @example
2080: @@@emph{expr V mcode}
2081: @end example
2082:
2083: @emph{Example (Using Variable)}
2084:
2085: @example
1.22 snw 2086: DEFAULT.USER> SET FOO="WRITE ""HELLO WORLD"",!"
2087: DEFAULT.USER> @@FOO
1.1 snw 2088:
2089: HELLO WORLD
2090:
1.22 snw 2091: DEFAULT.USER>
1.1 snw 2092: @end example
2093:
2094: @emph{Example (Using String Literal)}
2095:
2096: @example
1.22 snw 2097: DEFAULT.USER> @@"WRITE ""HELLO WORLD"",!"
1.1 snw 2098:
2099: HELLO WORLD
2100:
1.22 snw 2101: DEFAULT.USER>
1.1 snw 2102: @end example
2103:
2104: @emph{Example (Using Indirection)}
2105:
2106: @example
1.22 snw 2107: DEFAULT.USER> SET FOO="BAR"
1.1 snw 2108:
1.22 snw 2109: DEFAULT.USER> SET BAR="WRITE ""HELLO WORLD"",!"
1.1 snw 2110:
1.22 snw 2111: DEFAULT.USER> @@@@FOO
1.1 snw 2112:
2113: HELLO WORLD
2114:
1.22 snw 2115: DEFAULT.USER>
1.1 snw 2116: @end example
2117:
2118:
2119: @node !
2120: @section !
2121: @cindex !
2122: @cindex commands, !
2123: @cindex commands, external
2124: @cindex commands, non-standard
2125: @emph{FreeM Extension}
2126:
2127: 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}.
2128:
2129: 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.
2130:
2131: 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{%}.
2132:
2133: @code{%} contains the number of lines in the input or output. @code{%(1)..%(@emph{n})} contains the data for lines 1-@emph{n}.
2134:
2135: @node !!
2136: @section !!
2137: @cindex !!
2138: @cindex commands, !!
2139: @cindex commands, external
2140: @cindex commands, non-standard
2141: @emph{FreeM Extension}
2142:
2143: Launches a subshell within the FreeM direct mode, allowing the user to run operating system commands.
2144:
2145: @example
1.22 snw 2146: DEFAULT.USER> !!
1.1 snw 2147:
2148: Type Ctrl-D to exit from the shell
2149: $ uname -a
2150: Linux hesperos 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux
2151: $ exit
2152:
1.22 snw 2153: DEFAULT.USER>
1.1 snw 2154: @end example
2155:
2156:
2157: @node ABLOCK
2158: @section ABLOCK
2159: @cindex ABLOCK
2160: @cindex commands, ABLOCK
2161:
2162: 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).
2163:
2164: 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.
2165:
2166: @emph{Syntax}
2167:
2168: @example
2169: ABLOCK@emph{:postcondition}
2170: @end example
2171:
2172: 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.
2173:
2174: @example
2175: ABLOCK@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2176: @end example
2177:
2178: 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.
2179:
2180: @example
2181: ABLOCK@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN}
2182: @end example
2183:
2184: 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.
2185:
2186: @node ASSERT
2187: @section ASSERT
2188: @cindex ASSERT
2189: @cindex commands, ASSERT
2190: @cindex commands, debugging
2191: @cindex commands, implementation-specific
2192: @cindex commands, non-standard
2193: @emph{FreeM Extension}
2194:
2195: Triggers error @code{ASSERT} 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.
2196:
2197: The @code{ASSERT} error is catchable whether using standard-style, FreeM-style, or DSM 2.0-style error processing.
2198:
2199: @emph{Syntax}
2200:
2201: @example
2202: ASSERT@emph{:postcondition} @emph{<tvexpr>}
2203: @end example
2204:
2205: @emph{Example}
2206:
2207: @example
1.22 snw 2208: DEFAULT.USER> SET DEBUG=1
1.1 snw 2209:
2210:
1.22 snw 2211: DEFAULT.USER> ASSERT:DEBUG 1=1
1.1 snw 2212:
2213:
1.22 snw 2214: DEFAULT.USER> ASSERT:DEBUG 1=0
1.1 snw 2215:
2216:
2217: >> Error ZASSERT: programmer assertion failed in SYSTEM::^%SYSINIT [$STACK = 0]
2218: >> ASSERT:DEBUG 1=0
2219: ^
2220: @end example
2221:
2222: @node ASTART
2223: @section ASTART
2224: @cindex ASTART
2225: @cindex commands, ASTART
2226:
2227: Enables asynchronous event handling for one or more event classes.
2228:
2229: @emph{Syntax}
2230:
2231: @example
2232: ASTART@emph{:postcondition}
2233: @end example
2234:
2235: 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.
2236:
2237: @example
2238: ASTART@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2239: @end example
2240:
2241: 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.
2242:
2243: @example
2244: ASTART@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN})
2245: @end example
2246:
2247: 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.
2248:
2249: @node ASTOP
2250: @section ASTOP
2251: @cindex ASTOP
2252: @cindex commands, ASTOP
2253:
2254: Disables asynchronous event handling for one or more event classes.
2255:
2256: @emph{Syntax}
2257:
2258: @example
2259: ASTOP@emph{:postcondition}
2260: @end example
2261:
2262: 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.
2263:
2264: @example
2265: ASTOP@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2266: @end example
2267:
2268: 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.
2269:
2270: @example
2271: ASTOP@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN})
2272: @end example
2273:
2274: 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.
2275:
2276: @node AUNBLOCK
2277: @section AUNBLOCK
2278: @cindex AUNBLOCK
2279: @cindex commands, AUNBLOCK
2280:
2281: Decrements the event block counter for one or more event classes.
2282:
2283: @emph{Syntax}
2284:
2285: @example
2286: AUNBLOCK@emph{:postcondition}
2287: @end example
2288:
2289: 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.
2290:
2291: @example
2292: AUNBLOCK@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2293: @end example
2294:
2295: 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.
2296:
2297: @example
2298: AUNBLOCK@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN}
2299: @end example
2300:
2301: 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.
2302:
2303:
2304: @node BREAK
2305: @section BREAK
2306: @cindex BREAK
2307: @cindex commands, BREAK
2308:
2309: Interrupts running routine to allow interactive debugging.
2310:
2311: @emph{Syntax}
2312:
2313: @example
2314: @code{BREAK@emph{:postcondition}}
2315: @end example
2316:
2317: In its argumentless form, @code{BREAK} suspends execution of running code, provided the optional @emph{postcondition} is @emph{true} or omitted.
2318:
2319: @example
2320: @code{BREAK@emph{:postcondition} @emph{breakflag}}
2321: @end example
2322:
2323: @emph{FreeM Extension}
2324:
1.35 snw 2325: 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 2326: The following table enumerates the possible values of @emph{breakflag}
2327:
2328: @table @code
1.35 snw 2329: @item "DEBUG"
2330: Enters the interactive debugger
1.1 snw 2331: @item 0
2332: Disables @emph{Ctrl-C} handling
2333: @item -2
2334: Enables normal FreeM error handling
2335: @item 2
2336: Enables @emph{Digital Standard MUMPS} v2 error handling
2337: @item @emph{any integer value other than 0, 2, or -2}
2338: Enables @emph{Ctrl-C} handling
2339: @end table
2340:
2341: @node CLOSE
2342: @section CLOSE
2343: @cindex CLOSE
2344: @cindex commands, CLOSE
2345:
2346: Closes an input/output device.
2347:
2348: @emph{Syntax}
2349:
2350: @example
2351: @code{CLOSE@emph{:postcondition}}
2352: @end example
2353:
2354: 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.
2355:
2356: @example
2357: @code{CLOSE@emph{:postcondition} @emph{channel}}
2358: @end example
2359:
2360: 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.
2361:
2362: @node DO
2363: @section DO
2364: @cindex DO
2365: @cindex commands, DO
2366:
2367: 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.
2368:
2369: @emph{Syntax}
2370:
2371: @example
2372: DO[@emph{:postcondition}] @emph{entryref}[@emph{:postcondition}[,...]]
2373: @end example
2374:
1.35 snw 2375: @cartouche
2376: @quotation
2377: @emph{Non-Standard Behavior}
2378:
2379: 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.
2380: @end quotation
2381: @end cartouche
2382:
1.1 snw 2383: 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.
2384:
2385: @emph{Syntax}
2386:
2387: @example
2388: DO[@emph{:postcondition}]
2389: @end example
2390:
2391: @node ELSE
2392: @section ELSE
2393: @cindex ELSE
2394: @cindex commands, ELSE
2395:
2396: 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.
2397:
2398: @emph{Syntax}
2399:
2400: @example
2401: ELSE[@emph{:postcondition}]
2402: @end example
2403:
2404: @cartouche
2405: @quotation
2406: @emph{Non-Standard Behavior}
2407:
1.39 snw 2408: 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 2409:
1.35 snw 2410: 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 2411: @end quotation
2412: @end cartouche
2413:
2414: @node FOR
2415: @section FOR
2416: @cindex FOR
2417: @cindex commands, FOR
2418:
2419: 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.
2420:
2421: @emph{Syntax}
2422:
2423: @example
2424: FOR[@emph{:postcondition}]
2425: @end example
2426:
2427: @cartouche
2428: @quotation
2429: @emph{Non-Standard Behavior}
2430:
2431: 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.
2432:
2433: 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.
2434: @end quotation
2435: @end cartouche
2436:
2437: 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.
2438:
2439: 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}.
2440:
2441: @emph{Syntax}
2442:
2443: @example
2444: FOR[@emph{:postcondition}] @emph{glvn}=@emph{initializer-expression}:@emph{increment-expression}:@emph{max-expression}
2445: @end example
2446:
2447: @emph{Example}
2448:
2449: @example
1.22 snw 2450: DEFAULT.USER> FOR I=1:1:10 WRITE I,!
1.1 snw 2451:
2452: 1
2453: 2
2454: 3
2455: 4
2456: 5
2457: 6
2458: 7
2459: 8
2460: 9
2461: 10
2462:
1.22 snw 2463: DEFAULT.USER> FOR I=2:2:10 WRITE I,!
1.1 snw 2464:
2465: 2
2466: 4
2467: 6
2468: 8
2469: 10
2470: @end example
2471:
2472: 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.
2473:
2474: @emph{Syntax}
2475:
2476: @example
2477: FOR[@emph{:postcondition}] @emph{glvn}=@emph{expr1}[,..@emph{exprN}]
2478: @end example
2479:
2480: @emph{Example}
2481:
2482: @example
1.22 snw 2483: DEFAULT.USER> FOR I=60,"FOO",-3,"George",1450,$HOROLOG WRITE I,!
1.1 snw 2484:
2485: 60
2486: FOO
2487: -3
2488: George
2489: 1450
2490: 66106,52388
2491: @end example
2492:
2493: @node GOTO
2494: @section GOTO
2495: @cindex GOTO
2496: @cindex commands, GOTO
2497:
2498: 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}.
2499:
2500: @emph{Syntax}
2501:
2502: @example
2503: GOTO[@emph{:postcondition}] @emph{entryref}
2504: @end example
2505:
1.35 snw 2506: @cartouche
2507: @quotation
2508: @emph{Non-Standard Behavior}
2509:
2510: 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.
2511: @end quotation
2512: @end cartouche
2513:
2514:
1.1 snw 2515: @node HALT
2516: @section HALT
2517: @cindex HALT
2518: @cindex commands, HALT
2519:
2520: Halts program execution and frees resources allocated during execution, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2521:
2522: @emph{Syntax}
2523:
2524: @example
2525: HALT[@emph{:postcondition}]
2526: @end example
2527:
2528: @node HANG
2529: @section HANG
2530: @cindex HANG
2531: @cindex commands, HANG
2532:
2533: 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.
2534:
2535: @emph{Syntax}
2536:
2537: @example
2538: HANG[@emph{:postcondition}] @emph{expr}
2539: @end example
2540:
2541: @cartouche
2542: @quotation
2543: @emph{Non-Standard Behavior}
2544:
2545: FreeM supports sub-second values for @emph{expr}.
2546: @end quotation
2547: @end cartouche
2548:
2549: @node IF
2550: @section IF
2551: @cindex IF
2552: @cindex commands, IF
2553:
2554: 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.
2555:
2556: @emph{Syntax}
2557: @example
2558: IF[@emph{:postcondition}] @emph{tvexpr}[,...@emph{tvexpr}]
2559: @end example
2560:
2561: 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.
2562:
1.39 snw 2563:
1.1 snw 2564: @emph{Syntax}
2565: @example
1.39 snw 2566: IF[@emph{:postcondition}] @emph{command...}
1.1 snw 2567: @end example
2568:
1.39 snw 2569: @cartouche
2570: @quotation
2571: @emph{Style Recommendation}
2572:
2573: 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.
2574:
2575: 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.
2576: @end quotation
2577: @end cartouche
2578:
1.1 snw 2579: @node JOB
2580: @section JOB
2581: @cindex JOB
2582: @cindex commands, JOB
2583:
2584: Executes @emph{entryref} in a separate process, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2585:
2586: @emph{Syntax}
2587: @example
2588: JOB[@emph{:postcondition}] @emph{entryref}[:@emph{job-parameters}[:@emph{timeout}]]
2589: @end example
2590:
2591: If @emph{timeout} is supplied, FreeM will set @code{$TEST} to @emph{1} if the child process completes within @emph{timeout} seconds.
2592:
2593: @node KILL
2594: @section KILL
2595: @cindex KILL
2596: @cindex commands, KILL
2597:
2598: 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.
2599:
2600: @emph{Syntax}
2601: @example
2602: KILL[@emph{:postcondition}] @emph{glvn}[,...@emph{glvn}]
2603: @end example
2604:
2605: 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.
2606:
2607: @emph{Syntax}
2608: @example
2609: KILL[@emph{:postcondition}] (@emph{lvn}[,...@emph{lvn}])
2610: @end example
2611:
2612: In its argumentless form, @code{KILL} deletes all local variables, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2613:
2614: @emph{Syntax}
2615: @example
2616: KILL[@emph{:postcondition}]
2617: @end example
2618:
2619: @node KSUBSCRIPTS
2620: @section KSUBSCRIPTS
2621: @cindex KSUBSCRIPTS
2622: @cindex commands, KSUBSCRIPTS
2623:
2624: Kills only the descendant subscripts (but not the data value) of a referenced global, local, or SSVN (where allowed).
2625:
2626: @emph{Syntax}
2627:
2628: @example
2629: KSUBSCRIPTS@emph{:postcondition} @emph{var1},...
2630: @end example
2631:
2632: 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.
2633:
2634: @cartouche
2635: @quotation
2636: @emph{Note}
1.32 snw 2637: The below @emph{argumentless} and @emph{exclusive} forms of @code{KSUBSCRIPTS} are not implemented in FreeM, as of version 0.64.0-rc1, but are planned for a future release.
1.1 snw 2638: @end quotation
2639: @end cartouche
2640:
2641: @example
2642: KSUBSCRIPTS@emph{:postcondition}
2643: @end example
2644:
2645: 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.
2646:
2647: @example
2648: KSUBSCRIPTS@emph{:postcondition} (@emph{var1},...)
2649: @end example
2650:
2651: 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.
2652:
2653:
2654: @node KVALUE
2655: @section KVALUE
2656: @cindex KVALUE
2657: @cindex commands, KVALUE
2658:
2659: Kills only the data value (but not descendant subscripts) of a referenced global, local, or SSVN (where allowed).
2660:
2661: @emph{Syntax}
2662:
2663: @example
2664: KVALUE@emph{:postcondition} @emph{var1},...
2665: @end example
2666:
2667: 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.
2668:
2669: @cartouche
2670: @quotation
2671: @emph{Note}
1.32 snw 2672: The below @emph{argumentless} and @emph{exclusive} forms of @code{KVALUE} are not implemented in FreeM, as of version 0.64.0-rc1, but are planned for a future release.
1.1 snw 2673: @end quotation
2674: @end cartouche
2675:
2676: @example
2677: KVALUE@emph{:postcondition}
2678: @end example
2679:
2680: 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.
2681:
2682: @example
2683: KVALUE@emph{:postcondition} (@emph{var1},...)
2684: @end example
2685:
2686: 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.
2687:
2688: @node LOCK
2689: @section LOCK
2690: @cindex LOCK
2691: @cindex commands, LOCK
2692:
2693: Acquires or releases ownership of names.
2694:
2695: 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.
2696:
2697: @emph{Syntax}
2698: @example
2699: LOCK[@emph{:postcondition}]
2700: @end example
2701:
2702: 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}.
2703:
2704: If @code{LOCK} succeeds within @emph{timeout}, @code{$TEST} is set to @emph{1}. Otherwise, @code{$TEST} is set to @emph{0}.
2705:
2706: @emph{Syntax}
2707: @example
2708: LOCK[@emph{:postcondition}] [+|-]@emph{name}[:@emph{timeout}][,...[+|-]@emph{name}[:@emph{timeout}]]
2709: @end example
2710:
2711: @emph{Example}
2712:
1.26 snw 2713: This example will increment the lock counter for @code{^SNW} and decrement the lock counter for @code{^MJR}.
1.1 snw 2714:
2715: @example
1.26 snw 2716: LOCK +^SNW,-^MJR
1.1 snw 2717: @end example
2718:
2719: 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.
2720:
2721: If @code{LOCK} succeeds within @emph{timeout}, @code{$TEST} is set to @emph{1}. Otherwise, @code{$TEST} is set to @emph{0}.
2722:
2723: @emph{Syntax}
2724: @example
2725: LOCK[@emph{:postcondition}] @emph{name}[:@emph{timeout}][,...@emph{name}[:@emph{timeout}]]
2726: @end example
2727:
2728: @node MERGE
2729: @section MERGE
2730: @cindex MERGE
2731: @cindex commands, MERGE
2732:
2733: Merges the contents of one global, local, or SSVN subtree to another global, local, or SSVN.
2734:
2735: @emph{Syntax}
2736:
2737: @example
2738: @code{MERGE A=^$JOB}
2739: @end example
2740:
2741: 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.
2742:
2743: @node NEW
2744: @section NEW
2745: @cindex NEW
2746: @cindex commands, NEW
2747:
2748: In all forms of @code{NEW}, @emph{name} must be a local variable name or @code{NEW}-able structured or intrinsic system variable.
2749:
2750: 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.
2751:
2752: @emph{Syntax}
2753:
2754: @example
2755: NEW[@emph{:postcondition}] @emph{name}[,...@emph{name}]
2756: @end example
2757:
2758: 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.
2759:
2760: @emph{Syntax}
2761: @example
2762: NEW[@emph{:postcondition}] (@emph{name}[,...@emph{name}])
2763: @end example
2764:
2765: 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.
2766:
2767: @emph{Syntax}
2768: @example
2769: NEW@emph{:postcondition} @emph{name}=@emph{expr}
2770: @end example
2771:
2772: 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.
2773:
1.26 snw 2774: @emph{Syntax}
2775: @example
2776: NEW@emph{:postcondition} @emph{name}=$%@emph{^CLASS}(@emph{initializer-list})
2777: @end example
2778:
2779: 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).
2780:
1.1 snw 2781: @node OPEN
2782: @section OPEN
2783: @cindex OPEN
2784: @cindex commands, OPEN
2785:
2786: Opens sequential or socket I/O devices and files and associates them with a numeric FreeM input/output channel.
2787:
2788: @emph{Syntax (Sequential Files)}
2789:
2790: @example
2791: @code{OPEN@emph{:postcondition} @emph{channel}:"@emph{filename}/@emph{access-mode}"}
2792: @end example
2793:
2794: 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.
2795: The below table lists the valid options for @emph{access-mode}:
2796:
2797: @table @code
2798: @item r
2799: Read-only access
2800: @item w
2801: Create a new file for write access
2802: @item a
2803: Write access; append to existing file
2804: @item r+
2805: Read/write access
2806: @end table
2807:
2808: @cartouche
2809: @quotation
2810: @emph{I/O Path}
2811:
2812: 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
2813: access files in other directories, you must first set the @emph{I/O Path} in @code{^$JOB($JOB,"IOPATH")}.
2814:
2815: The following example will set the I/O path to @code{/etc}:
2816:
2817: @example
2818: @code{SET ^$JOB($JOB,"IOPATH")="/etc"}
2819: @end example
2820:
2821: @end quotation
2822: @end cartouche
2823:
2824: 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}.
2825:
2826: @emph{Syntax (Network Sockets)}
2827:
2828: 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.
2829:
2830: @example
2831: OPEN@emph{:postcondition} @emph{socket-channel}:"@emph{hostname-or-address}:@emph{port}:@emph{address-family}:@emph{connection-type}"
2832: @end example
2833:
2834: @emph{Socket Parameters}
2835:
2836: @table @emph
2837:
2838: @item socket-channel
2839: The socket I/O channel to use. This must be in the range of 100-255.
2840:
2841: @item hostname-or-address
2842: 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.
2843:
2844: @item port
2845: The TCP or UDP port to which the socket will connect on the remote host.
2846:
2847: @item address-family
2848: The address family to use. Either @emph{IPV4} or @emph{IPV6}.
2849:
2850: @item connection-type
2851: Which connection type to use. Either @emph{TCP} or @emph{UDP}.
2852:
2853: @end table
2854:
2855: If you do not specify the address family and connection type, they will default to @emph{IPV4} and @emph{TCP}, respectively.
2856:
2857: @node QUIT
2858: @section QUIT
2859: @cindex QUIT
2860: @cindex commands, QUIT
2861:
2862: @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.
2863:
2864: @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}.
2865:
2866: Argumentless @code{QUIT} may also be used to exit a @code{FOR} loop occurring on the same line.
2867:
2868: @emph{Syntax}
2869: @example
2870: QUIT[@emph{:postcondition}] [@emph{expr}]
2871: @end example
2872:
2873: @node READ
2874: @section READ
2875: @cindex READ
2876: @cindex commands, READ
2877:
2878: 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.
2879:
2880: @emph{Syntax}
2881: @example
2882: READ[@emph{:postcondition}] @emph{read-argument}[,...@emph{read-argument}]
2883: @end example
2884:
2885: Each @emph{read-argument} may be one of the following:
2886:
2887: @table @asis
2888:
2889: @item String Literal
2890: String literal @emph{read-argument}s will be output to @code{$IO} unmodified.
2891:
2892: @item Format Specifier
2893: One or more of the following:
2894:
2895: @table @asis
2896: @item @code{!} (newline)
2897: Advances the cursor down by one line and returns it to the first column.
2898:
2899: @item @code{#} (form-feed)
2900: Advances the screen down by @code{$ZROWS} and moves the cursor to the upper-left corner of the screen.
2901:
2902: @item @code{?@emph{n}} (position)
2903: Advances the cursor and @code{$X} forward to position @emph{n}.
2904:
2905: @end table
2906:
2907: @item Single-Character Read (@code{*@emph{variable-name}[@emph{:timeout}]})
2908: 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}.
2909:
2910: @item Variable-Length Character Read (@code{@emph{variable-name}[@emph{:timeout}]})
2911: 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}.
2912:
2913: @item Fixed-Length Character Read (@code{@emph{variable-name}#@emph{count}[@emph{:timeout}]})
2914: 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}.
2915:
2916: @item Control Mnemonic (@code{/@emph{control-mnemonic}[@emph{(arg1[,...argN])}]})
2917: Outputs X3.64 control mnemonic @emph{control-mnemonic} to @code{$IO}. Please see the appendix on X3.64 Control Mnemonics for more information.
2918:
2919: @end table
2920:
2921: @node SET
2922: @section SET
2923: @cindex SET
2924: @cindex commands, SET
2925:
2926: The @code{SET} command places values into one or more variables, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2927:
2928: @emph{Syntax}
2929: @example
2930: SET[@emph{:postcondition}] @emph{set-argument}[=@emph{expression} | @emph{postfix-operator}][@emph{,...set-argument}[=@emph{expression} | @emph{postfix-operator}]]
2931: @end example
2932:
2933: Each @emph{set-argument} can be:
2934:
2935: @table @asis
2936: @item @emph{variable-name}
2937: A local variable, global variable, writable intrinsic special variable, or writable structured system variable.
2938:
2939: @item @emph{lhs-function}
2940: @code{$EXTRACT} or @code{$PIECE}.
2941: @end table
2942:
2943: 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}.
2944:
2945: 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.
2946:
2947: @emph{Example (postfix-operator)}
2948:
2949: @example
2950: SET A++,B-- ; increments A, decrements B
2951: @end example
2952:
2953: @node TCOMMIT
2954: @section TCOMMIT
2955: @cindex TCOMMIT
2956: @cindex commands, TCOMMIT
2957:
2958: Commits all pending transactions to the data files, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2959:
2960: @emph{Syntax}
2961: @example
2962: TCOMMIT[@emph{:postcondition}]
2963: @end example
2964:
2965: @node THEN
2966: @section THEN
2967: @cindex THEN
2968: @cindex commands, THEN
2969:
2970: 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}.
2971:
2972: @emph{Example}
2973: @example
2974: IF 1 THEN WRITE "HELLO!",!
2975: @end example
2976:
2977: @node TROLLBACK
2978: @section TROLLBACK
2979: @cindex TROLLBACK
2980: @cindex commands, TROLLBACK
2981:
2982: Rolls back all pending transactions for the current process, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2983:
2984: @emph{Syntax}
2985:
2986: @example
2987: TROLLBACK[@emph{:postcondition}]
2988: @end example
2989:
2990: @node TSTART
2991: @section TSTART
2992: @cindex TSTART
2993: @cindex commands, TSTART
2994:
2995: 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.
2996:
2997: If a transaction is restartable, variables in the @emph{variables-list} will be restored to their original values on a restart of the transaction.
2998:
2999: @emph{Syntax}
3000:
3001: @example
3002: TSTART[@emph{:postcondition}] @emph{<variables-list>}:@emph{<transaction-parameters>}
3003: @end example
3004:
3005: @emph{<variables-list>} can be:
3006:
3007: @table @asis
3008:
3009: @item @code{()}
3010: Do not save off any local variables. Makes the transaction non-restartable.
3011:
3012: @item @code{*}
3013: Save off all local variables. Makes the transaction restartable.
3014:
3015: @item @code{@emph{variableName}}
3016: Saves off only one local variable, @emph{variableName}. Makes the transaction restartable.
3017:
3018: @item @code{(@emph{variableName1},...,@emph{variableNameN})}
3019: Saves off all local variables listed. Makes the transaction restartable.
3020:
3021: @end table
3022:
3023: @emph{<transaction-parameters>} can be:
3024:
3025: @table @asis
3026:
3027: @item @code{S[ERIAL]}
3028: 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.
3029:
3030: @item @code{T[RANSACTIONID]=@emph{transaction-id}}
3031: Sets the ID of the transaction to @emph{transaction-id}
3032:
3033: @end table
3034:
3035: If you are using more than one transaction parameter, surround all of them in parentheses and separate them with commas, e.g.:
3036:
3037: @example
3038: TSTART (FOO,BAR):(SERIAL,TRANSACTIONID="FOO")
3039: @end example
3040:
3041:
3042: @node USE
3043: @section USE
3044: @cindex USE
3045: @cindex commands, USE
3046:
3047: 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.
3048:
3049: @emph{Syntax (Terminal)}
3050:
3051: @example
3052: 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})]
3053: @end example
3054:
3055: For terminals, @emph{io-channel} must be 0.
3056:
3057: Semantic and functional description of each device parameter TBA.
3058:
3059: @emph{Syntax (Sequential Files)}
3060:
3061: @example
3062: USE@emph{:postcondition} @emph{io-channel}[:@emph{seek-position}:@emph{terminator}:@emph{nodelay})]
3063: @end example
3064:
3065: For sequential files, @emph{io-channel} must be in the range 1-99.
3066:
3067: Semantic and functional description of each device parameter TBA.
3068:
3069: @emph{Syntax (Network Sockets)}
3070:
3071: @example
3072: USE@emph{:postcondition} @emph{io-channel}
3073: @end example
3074:
3075: 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.
3076:
3077: @example
3078: USE@emph{:postcondition} @emph{io-channel}:/CONNECT
3079: @end example
3080:
3081: 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).
3082:
3083: For network sockets, @emph{io-channel} must be in the range 100-255.
3084:
3085: @node VIEW
3086: @section VIEW
3087: @cindex VIEW
3088: @cindex commands, VIEW
3089:
3090: Provides write access to various FreeM internal parameters, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
3091:
3092: @emph{Syntax}
3093: @example
3094: VIEW[@emph{:postcondition}] @emph{view-number}[:@emph{view-argument}[:@emph{view-argument}...]]
3095: @end example
3096:
3097: The @emph{view-number} argument can be one of the following:
3098:
3099: @table @asis
3100:
3101: @item @code{21} - Close All Globals
3102: Closes all global data files open in the current process. Takes no arguments.
3103:
3104: @emph{Syntax}
3105: @example
3106: VIEW 21
3107: @end example
3108:
3109: @item @code{52} - Set G0 Input Translation Table for @code{$IO}
3110:
3111: @emph{Syntax}
3112: @example
3113: VIEW 52:@emph{expr V trantab}
3114: @end example
3115:
3116: @item @code{53} - Set G0 Output Translation Table for @code{$IO}
3117:
3118: @emph{Syntax}
3119: @example
3120: VIEW 53:@emph{expr V trantab}
3121: @end example
3122:
3123: @item @code{54} - Set G1 Input Translation Table for @code{$IO}
3124:
3125: @emph{Syntax}
3126: @example
3127: VIEW 54:@emph{expr V trantab}
3128: @end example
3129:
3130: @item @code{55} - Set G1 Output Translation Table for @code{$IO}
3131:
3132: @emph{Syntax}
3133: @example
3134: VIEW 55:@emph{expr V trantab}
3135: @end example
3136:
3137: @item @code{62} - Set @code{$RANDOM} Seed Number
3138: Sets the seed number used by @code{$RANDOM} to @emph{numexpr}.
3139:
3140: @emph{Syntax}
3141: @example
3142: VIEW 62:@emph{numexpr}
3143: @end example
3144:
3145: @item @code{63} - Set @code{$RANDOM} Parameter A
3146: Sets the number used for @code{$RANDOM} Parameter A to @emph{numexpr}.
3147:
3148: @emph{Syntax}
3149: @example
3150: VIEW 63:@emph{numexpr}
3151: @end example
3152:
3153: @item @code{64} - Set @code{$RANDOM} Parameter B
3154: Sets the number used for @code{$RANDOM} Parameter B to @emph{numexpr}.
3155:
3156: @emph{Syntax}
3157: @example
3158: VIEW 64:@emph{numexpr}
3159: @end example
3160:
3161: @item @code{65} - Set @code{$RANDOM} Parameter C
3162: Sets the number used for @code{$RANDOM} Parameter C to @emph{numexpr}.
3163:
3164: @emph{Syntax}
3165: @example
3166: VIEW 65:@emph{numexpr}
3167: @end example
3168:
3169: @item @code{66} - Set or Clear @code{SIGTERM} Handling Flag
3170: 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.
3171:
3172: @emph{Syntax}
3173: @example
3174: VIEW 66:@emph{tvexpr}
3175: @end example
3176:
3177: @item @code{67} - Set or Clear @code{SIGHUP} Handling Flag
3178: 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.
3179:
3180: @emph{Syntax}
3181: @example
3182: VIEW 67:@emph{tvexpr}
3183: @end example
3184:
3185: @item @code{70} - Set @code{$ZSORT}/@code{$ZSYNTAX} Flag
3186: Selects whether @code{$ZS} resolves to @code{$ZSORT} or @code{$ZSYNTAX}.
3187:
3188: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZSYNTAX}. Otherwise, selects @code{$ZSORT}.
3189:
3190: @emph{Syntax}
3191: @example
3192: VIEW 70:@emph{tvexpr}
3193: @end example
3194:
3195: @item @code{71} - Set @code{$ZNEXT}/@code{$ZNAME} Flag
3196: Selects whether @code{$ZN} resolves to @code{$ZNEXT} or @code{$ZNAME}.
3197:
3198: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZNAME}. Otherwise, selects @code{$ZNEXT}.
3199:
3200: @emph{Syntax}
3201: @example
3202: VIEW 71:@emph{tvexpr}
3203: @end example
3204:
3205: @item @code{72} - Set @code{$ZPREVIOUS}/@code{$ZPIECE} Flag
3206: Selects whether @code{$ZP} resolves to @code{$ZPREVIOUS} or @code{$ZPIECE}.
3207:
3208: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZPIECE}. Otherwise, selects @code{$ZPREVIOUS}.
3209:
3210: @emph{Syntax}
3211: @example
3212: VIEW 72:@emph{tvexpr}
3213: @end example
3214:
3215: @item @code{73} - Set @code{$ZDATA}/@code{$ZDATE} Flag
3216: Selects whether @code{$ZD} resolves to @code{$ZDATA} or @code{$ZDATE}.
3217:
3218: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZDATE}. Otherwise, selects @code{$ZDATA}.
3219:
3220: @emph{Syntax}
3221: @example
3222: VIEW 73:@emph{tvexpr}
3223: @end example
3224:
3225: @item @code{79} - Set Old @code{ZJOB} vs. New @code{ZJOB} Flag
3226: If @emph{tvexpr} evaluates to @emph{true}, sets the @code{ZJOB} mode to new, otherwise, sets it to old.
3227:
3228: @emph{Syntax}
3229: @example
3230: VIEW 79:@emph{tvexpr}
3231: @end example
3232:
3233: @item @code{80} - Set or Clear 8-Bit Flag
3234: If @emph{tvexpr} evaluates to @emph{true}, sets FreeM to 8-bit mode. Otherwise, sets FreeM to 7-bit mode.
3235:
3236: @emph{Syntax}
3237: @example
3238: VIEW 80:@emph{tvexpr}
3239: @end example
3240:
3241: @item @code{81} - Set or Clear PF1 Flag
3242: If @emph{tvexpr} evaluates to @emph{true}, sets the @code{PF1} flag. We do not yet know what this does.
3243:
3244: @emph{Syntax}
3245: @example
3246: VIEW 81:@emph{tvexpr}
3247: @end example
3248:
3249: @item @code{83} - Set or Clear Text in @code{$ZERROR} Flag
3250: 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}.
3251:
3252: @emph{Syntax}
3253: @example
3254: VIEW 83:@emph{tvexpr}
3255: @end example
3256:
3257: @item @code{92} - Set Type Mismatch Error Flag on @code{EUR2DEM}
3258: 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.
3259:
3260: @emph{Syntax}
3261: @example
3262: VIEW 92:@emph{tvexpr}
3263: @end example
3264:
3265: @item @code{93} - Define @code{ZKEY} Production Rule
3266: We do not know what this does.
3267:
3268: @item @code{96} - Set Global Prefix
3269: Forces global data filenames to be prefixed with the result of @emph{expr}.
3270:
3271: @emph{Syntax}
3272: @example
3273: VIEW 96:@emph{expr V string}
3274: @end example
3275:
3276: @item @code{97} - Set Global Postfix
3277: Forces global data filenames to be postfixed with the result of @emph{expr}.
3278:
3279: @emph{Syntax}
3280: @example
3281: VIEW 97:@emph{expr V string}
3282: @end example
3283:
3284: @item @code{98} - Set Routine Extension
3285: Sets the default extension for M routine filenames to the result of @emph{expr}.
3286:
3287: @emph{Syntax}
3288: @example
3289: VIEW 98:@emph{expr V string}
3290: @end example
3291:
3292: @item @code{101} - Set @code{ierr}
3293: Sets the FreeM internal @code{ierr} value to @emph{intexpr}. Used by some FreeM polyfills (commands or functions implemented in M code).
3294:
3295: @emph{Syntax}
3296: @example
3297: VIEW 101:@emph{intexpr}
3298: @end example
3299:
3300: @item @code{102} - Set @code{ierr} (Deferred)
3301: 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.
3302:
3303: @emph{Syntax}
3304: @example
3305: VIEW 102:@emph{intexpr}
3306: @end example
3307:
3308: @item @code{103} - Signal @code{MERGE} to @code{^$WINDOW} Complete
3309: Signals FreeM's MWAPI implementation that a @code{MERGE} to @code{^$WINDOW} or descendant subscripts thereof has completed.
3310:
3311: @emph{Syntax}
3312: @example
3313: VIEW 103[@emph{:subscript}]
3314: @end example
3315:
3316: @item @code{110} - Set Local @code{$ORDER}/@code{$QUERY} Data Value
3317: Sets the local variable @code{$ORDER}/@code{$QUERY} data value to the result of @emph{expr}. We're not entirely sure what this is.
3318:
3319: @emph{Syntax}
3320: @example
3321: VIEW 110:@emph{expr}
3322: @end example
3323:
3324: @item @code{111} - Set Global @code{$ORDER}/@code{$QUERY} Data Value
3325: Sets the global variable @code{$ORDER}/@code{$QUERY} data value to the result of @emph{expr}. We're not entirely sure what this is.
3326:
3327: @emph{Syntax}
3328: @example
3329: VIEW 111:@emph{expr}
3330: @end example
3331:
3332: @item @code{113} - Set @code{termio} Information
3333: We don't know what this does.
3334:
3335: @item @code{133} - Remember @code{ZLOAD} Directory on @code{ZSAVE}
3336: We don't know what this does, but it takes a @emph{tvexpr}.
3337:
3338: @emph{Syntax}
3339: @example
3340: VIEW 133:@emph{tvexpr}
3341: @end example
3342:
3343: @end table
3344:
3345:
3346:
3347: @node WRITE
3348: @section WRITE
3349: @cindex WRITE
3350: @cindex commands, WRITE
3351:
3352: @node XECUTE
3353: @section XECUTE
3354: @cindex XECUTE
3355: @cindex commands, XECUTE
3356:
3357: @node ZBREAK
3358: @section ZBREAK
3359: @cindex ZBREAK
3360: @cindex commands, ZBREAK
3361: @cindex commands, debugging
3362: @cindex commands, implementation-specific
3363: @cindex commands, non-standard
3364: @emph{FreeM Extension}
3365:
1.42 snw 3366: @node ZCONST
3367: @section ZCONST
3368: @cindex ZCONST
3369: @cindex commands, ZCONST
3370: @cindex commands, non-standard
3371: @emph{FreeM Extension}
3372:
3373: 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.
3374:
3375: Constants must only be locals, and globals are not supported.
3376:
3377: @emph{Syntax}
3378:
3379: @example
3380: @code{ZCONST@emph{:postcondition} @emph{mref1}=@emph{initial-value1},...,@emph{mrefN}=@emph{initial-valueN}}
3381: @end example
3382:
1.1 snw 3383: @node ZGO
3384: @section ZGO
3385: @cindex ZGO
3386: @cindex commands, ZGO
3387: @cindex commands, implementation-specific
3388: @cindex commands, non-standard
3389: @emph{FreeM Extension}
3390:
3391: @node ZHALT
3392: @section ZHALT
3393: @cindex ZHALT
3394: @cindex commands, ZHALT
3395: @cindex commands, implementation-specific
3396: @cindex commands, non-standard
3397: @emph{FreeM Extension}
3398:
3399: @node ZINSERT
3400: @section ZINSERT
3401: @cindex ZINSERT
3402: @cindex commands, ZINSERT
3403: @cindex commands, implementation-specific
3404: @cindex commands, non-standard
3405: @emph{FreeM Extension}
3406:
3407: @node ZJOB
3408: @section ZJOB
3409: @cindex ZJOB
3410: @cindex commands, ZJOB
3411: @cindex commands, implementation-specific
3412: @cindex commands, non-standard
3413: @emph{FreeM Extension}
3414:
3415: 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.
3416:
3417: For more information, see @code{JOB}.
3418:
3419: @node ZLOAD
3420: @section ZLOAD
3421: @cindex ZLOAD
3422: @cindex commands, ZLOAD
3423: @cindex commands, implementation-specific
3424: @cindex commands, non-standard
3425: @emph{FreeM Extension}
3426:
3427: Loads routine @emph{<routine-name>} into FreeM's routine buffer, provided the optional @emph{postcondition} is @emph{true} or omitted.
3428:
3429: @emph{Syntax}
3430:
3431: @example
3432: ZLOAD@emph{:postcondition} @emph{<routine-name>}
3433: @end example
3434:
1.42 snw 3435:
3436: @node ZMAP
3437: @section ZMAP
3438: @cindex ZMAP
3439: @cindex commands, ZMAP
3440: @cindex commands, implementation-specific
3441: @cindex commands, non-standard
3442:
3443: 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.
3444:
3445: @emph{Syntax}
3446:
3447: @example
3448: ZMAP[@emph{:postcondition}] GLOBAL @emph{gvn}=@emph{expr V namespace}
3449: @end example
3450:
1.1 snw 3451: @node ZNEW
3452: @section ZNEW
3453: @cindex ZNEW
3454: @cindex commands, ZNEW
3455: @cindex commands, implementation-specific
3456: @cindex commands, non-standard
3457: @emph{FreeM Extension}
3458:
3459: @node ZPRINT
3460: @section ZPRINT
3461: @cindex ZPRINT
3462: @cindex commands, ZPRINT
3463: @cindex commands, implementation-specific
3464: @cindex commands, non-standard
3465: @emph{FreeM Extension}
3466:
3467: Prints the contents of the current routine buffer, provided the optional @emph{postcondition} is @emph{true} or omitted.
3468:
3469: @emph{Syntax}
3470:
3471: @example
3472: ZPRINT@emph{:postcondition}
3473: @end example
3474:
3475: @node ZQUIT
3476: @section ZQUIT
3477: @cindex ZQUIT
3478: @cindex commands, ZQUIT
3479: @cindex commands, implementation-specific
3480: @cindex commands, non-standard
3481: @emph{FreeM Extension}
3482:
3483: In its single-argument form, quits from @emph{levels} levels of the stack, provided the optional @emph{postcondition} is @emph{true} or omitted.
3484:
3485: In its argumentless form, quits from @code{$STACK} levels of the stack, provided the optional @emph{postcondition} is @emph{true} or omitted.
3486:
3487: @emph{Syntax}
3488:
3489: @example
3490: @code{ZQUIT@emph{:postcondition} [@emph{levels}]}
3491: @end example
3492:
3493: @node ZREMOVE
3494: @section ZREMOVE
3495: @cindex ZREMOVE
3496: @cindex commands, ZREMOVE
3497: @cindex commands, implementation-specific
3498: @cindex commands, non-standard
3499: @emph{FreeM Extension}
3500:
3501: @node ZSAVE
3502: @section ZSAVE
3503: @cindex ZSAVE
3504: @cindex commands, ZSAVE
3505: @cindex commands, implementation-specific
3506: @cindex commands, non-standard
3507: @emph{FreeM Extension}
3508:
1.42 snw 3509:
3510: @node ZTHROW
3511: @section ZTHROW
3512: @cindex ZTHROW
3513: @cindex commands, ZTHROW
3514: @cindex commands, non-standard
3515: @emph{FreeM Extension}
3516:
3517: Raises an error condition as long as the optional @emph{postcondition} is @emph{true} or omitted.
3518:
3519: @emph{Syntax}
3520:
3521: @example
3522: @code{ZTHROW@emph{:postcondition} @emph{expr V error-code}}
3523: @end example
3524:
3525: @emph{Example}
3526:
3527: @example
3528: @code{ZTHROW "M102"}
3529: @end example
3530:
1.1 snw 3531: @node ZTRAP
3532: @section ZTRAP
3533: @cindex ZTRAP
3534: @cindex commands, ZTRAP
3535: @cindex commands, debugging
3536: @cindex commands, implementation-specific
3537: @cindex commands, non-standard
3538: @emph{FreeM Extension}
3539:
1.42 snw 3540: @node ZUNMAP
3541: @section ZUNMAP
3542: @cindex ZUNMAP
3543: @cindex commands, ZUNMAP
3544: @cindex commands, implementation-specific
3545: @cindex commands, non-standard
3546:
3547: Removes any mapping connecting @emph{gvn} to a non-default namespace, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
3548:
3549: @emph{Syntax}
3550:
3551: @example
3552: ZUNMAP GLOBAL @emph{gvn}
3553: @end example
3554:
3555: @node ZWATCH
3556: @section ZWATCH
3557: @cindex ZWATCH
3558: @cindex commands, ZWATCH
3559: @cindex commands, debugging
3560: @cindex commands, implementation-specific
3561: @cindex commands, non-standard
3562: @emph{FreeM Extension}
3563:
3564: Sets a watchpoint on a global, local, or SSVN node.
3565:
3566: @emph{Syntax}
3567:
3568:
3569: In its @emph{argumentless} form, @code{ZWATCH} toggles watchpoints on and off, provided the optional @emph{postcondition} is @emph{true} or omitted.
3570:
3571: @example
3572: ZWATCH[@emph{:postcondition}]
3573: @end example
3574:
3575: In its @emph{inclusive} form, @code{ZWATCH} adds, removes, or examines watchpoints, provided the optional @emph{postcondition} is @emph{true} or omitted.
3576:
3577: A @code{+} adds a new watchpoint to the following variable.
3578:
3579: A @code{-} removes an existing watchpoint for the following variable.
3580:
3581: A @code{?} examines the status of a watchpoint for the following variable.
3582:
3583: @example
3584: ZWATCH[@emph{:postcondition}] [+|-|?]@emph{var1}...,[+|-|?]@emph{varN}
3585: @end example
3586:
3587:
3588: 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)}.
3589:
3590: @example
3591: DEFAULT.USER> ZWATCH
3592:
3593: Watchpoints enabled.
3594:
3595: DEFAULT.USER> ZWATCH +^SNW(1)
3596:
3597: Added '^SNW("1")' to the watchlist.
3598:
3599: DEFAULT.USER> SET ^SNW(1)="new value"
3600:
3601: >> WATCHPOINT: ^SNW("1") => 'new value' (changed 1 times)
3602:
3603: @end example
3604:
3605: The following example will remove that watchpoint:
3606:
3607: @example
3608: DEFAULT.USER> ZWATCH -^SNW(1)
3609:
3610: Removed '^SNW("1")' from the watchlist.
3611:
3612: DEFAULT.USER> ZWATCH ?^SNW(1)
3613:
3614: '^SNW("1")' is not being watched.
3615: @end example
3616:
3617: @node ZWITH
3618: @section ZWITH
3619: @cindex ZWITH
3620: @cindex commands, ZWITH
3621: @cindex commands, non-standard
3622: @emph{FreeM Extension}
3623:
3624: NOTE: This command may be deprecated and removed in future FreeM releases.
3625:
3626: Sets a prefix to be applied to all subsequent local variable or constant references.
3627:
3628: @emph{Syntax}
3629:
3630: @example
3631: @code{ZWITH@emph{:postcondition} @emph{var-prefix}}
3632: @end example
3633:
3634: 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.
3635:
3636: The @emph{var-prefix} argument may be a string literal or any valid FreeM expression.
3637:
3638: @example
3639: @code{ZWITH@emph{:postcondition}}
3640: @end example
3641:
3642: 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 ""}.
3643:
3644:
3645:
3646:
3647:
3648:
3649:
3650:
1.1 snw 3651: @node ZWRITE
3652: @section ZWRITE
3653: @cindex ZWRITE
3654: @cindex commands, ZWRITE
3655: @cindex commands, implementation-specific
3656: @cindex commands, non-standard
3657: @emph{FreeM Extension}
3658:
3659: Writes the names and values of M variables to @code{$IO}.
3660:
3661: @emph{Syntax}
3662:
3663: @example
3664: ZWRITE@emph{:postcondition}
3665: @end example
3666:
3667: 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.
3668:
3669: @example
3670: ZWRITE@emph{:postcondition} @emph{ArrayName},@dots{}
3671: @end example
3672:
3673: 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.
3674:
3675: @example
3676: ZWRITE@emph{:postcondition} (@emph{ArrayName},@dots{})
3677: @end example
3678:
3679: 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.
3680:
3681:
3682: @node Structured System Variables
3683: @chapter Structured System Variables
3684: @cindex variables, structured system
3685: @cindex structured system variables
3686: @cindex SSVNs
3687:
3688: @menu
3689: * ^$CHARACTER:: Character set information.
3690: * ^$DEVICE:: Device information.
3691: * ^$DISPLAY:: Information about graphic display.
3692: * ^$EVENT:: Information supplied about a synchronous or asynchronous event.
3693: * ^$GLOBAL:: Information about M globals.
3694: * ^$JOB:: Information about and control of FreeM jobs.
3695: * ^$LOCK:: Information about the FreeM lock table.
3696: * ^$OBJECT:: Information about FreeM objects.
3697: * ^$ROUTINE:: Information about FreeM routines.
3698: * ^$SYSTEM:: Information about the running system.
3699: * ^$WINDOW:: Configuration of MWAPI windows.
3700: * ^$ZPROCESS:: Information about and control of system processes.
3701: * ^$ZRPI:: Information about and control of Raspberry Pi GPIO pins.
3702: @end menu
3703:
3704: SSVN subscripts are each described in the following format:
3705:
3706: @table @asis
3707: @item @code{@emph{<ssvn-subscript-name>}} +/-R +/-U +/-D
3708: @end table
3709:
3710: 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.
3711:
3712: @node ^$CHARACTER
3713: @section ^$CHARACTER
3714: @cindex ^$CHARACTER
3715: @cindex structured system variables, ^$CHARACTER
3716:
3717: 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"}.
3718:
3719: The following values for the second subscript are supported:
3720:
3721: @table @asis
3722:
3723: @item @code{IDENT} +R -U -D
3724: Returns the empty string.
3725:
3726: @item @code{COLLATE} +R -U -D
3727: Returns the empty string.
3728:
3729: @item @code{INPUT} +R -U -D
3730: Returns the empty string if the third subscript is @code{M}, otherwise, raises error @code{M38}.
3731:
3732: @item @code{OUTPUT} +R -U -D
3733: Returns the empty string if the third subscript is @code{M}, otherwise, raises error @code{M38}.
3734:
3735: @end table
3736:
3737: @node ^$DEVICE
3738: @section ^$DEVICE
3739: @cindex ^$DEVICE
3740: @cindex structured system variables, ^$DEVICE
3741:
3742: FreeM implements several important pieces of functionality in the @code{^$DEVICE} SSVN.
3743:
3744: The first subscript of @code{^$DEVICE} represents the I/O channel of an @code{OPEN}ed device.
3745:
3746: The following values for the second subscript are supported:
3747:
3748: @table @asis
3749:
3750: @item @code{$DEVICE}
3751: Returns the value of @code{$DEVICE} for the specified I/O channel.
3752:
3753: @item @code{$X} +R -U -D
3754: Returns the horizontal cursor position of a terminal device. Only valid if the I/O channel is @code{0}.
3755:
3756: @item @code{$Y} +R -U -D
3757: Returns the vertical cursor position of a terminal device. Only valid if the I/O channel is @code{0}.
3758:
3759: @item @code{ROWS} +R -U -D
3760: Returns the number of character rows on the terminal device. Only valid if the I/O channel is @code{0}.
3761:
3762: @item @code{COLUMNS} +R -U -D
3763: Returns the number of character columns on the terminal device. Only valid if the I/O channel is @code{0}.
3764:
3765: @item @code{CHARACTER} +R -U -D
3766: Returns the character set of the specified I/O channel; always @code{M} in the current implementation.
3767:
3768: @item @code{INPUT_BUFFER} +R +U -D
3769: 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.
3770:
3771: @item @code{NAME} +R -U -D
3772: Returns the operating system's name for the file, device, or socket attached to the specified I/O channel.
3773:
3774: @item @code{FD} +R -U -D
3775: Returns the UNIX file descriptor of the specified I/O channel.
3776:
3777: @item @code{MODE} +R -U -D
3778: 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.
3779:
3780: @item @code{EOF} +R -U -D
3781: 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.
3782:
3783: @item @code{LENGTH} +R -U -D
3784: 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.
3785:
3786: @item @code{NAMESPACE} +R -U -D
3787: Returns the current @emph{mnemonic-space} in use for the referenced I/O channel. Always @code{X364} for terminals and blank for sequential files.
3788:
3789: @item @code{TYPE} +R -U -D
3790: Returns either @code{1,FILE}, @code{2,SOCKET}, or @code{4,TERMINAL}, depending on the device type associated with the specified I/O channel.
3791:
3792: @item @code{OPTIONS} -R -U -D
3793: 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:
3794:
3795: @table @asis
3796:
3797: @item @code{DSW} +R +U -D
3798: Sets or returns the current @emph{Device Status Word} controlling terminal characteristics. Only valid for I/O channel 0.
3799:
3800: @item @code{TERMINATOR} +R +U -D
3801: 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).
3802:
3803: @item @code{TERMID} +R -U -D
3804: Returns the type of terminal connected to channel 0. Only valid for I/O channel 0.
3805:
3806: @item @code{ECHO} +R +U -D
3807: 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.
3808:
3809: @item @code{DELMODE} +R +U -D
3810: 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.
3811:
3812: @item @code{ESCAPE} +R +U -D
3813: 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.
3814:
3815: @item @code{CONVUPPER} +R +U -D
3816: 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.
3817:
3818: @item @code{DELEMPTY} +R +U -D
3819: 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.
3820:
3821: @item @code{NOCTRLS} +R +U -D
3822: TBD. Only valid for I/O channel 0. Corresponds to bit 20 of the Device Status Word.
3823:
3824: @item @code{CTRLOPROC} +R +U -D
3825: 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.
3826:
3827: @item @code{NOTYPEAHEAD} +R +U -D
3828: 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.
3829: @end table
3830: @end table
3831:
3832: @emph{Example}
3833:
3834: 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.
3835:
3836: @example
3837: SET ^$JOB($JOB,"IOPATH")="/etc" ; set I/O path to /etc
3838: OPEN 1:"freem.conf/r" ; open freem.conf for reading
3839: ;
3840: ; read until we run out of lines
3841: ;
3842: FOR USE 1 READ LINE USE 0 QUIT:^$DEVICE(1,"EOF") D
3843: . WRITE LINE,!
3844: ;
3845: CLOSE 1
3846: QUIT
3847: @end example
3848:
3849: @node ^$DISPLAY
3850: @section ^$DISPLAY
3851: @cindex ^$DISPLAY
3852: @cindex structured system variables, ^$DISPLAY
3853:
3854: 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.
3855:
3856: The following second-level subscripts and specified descendant subscripts are supported:
3857:
3858: @table @asis
3859:
3860: @item @code{CLIPBOARD} +R +U +D
3861: Retrieves, sets, or erases the contents of the system clipboard.
3862:
3863: @item @code{PLATFORM} +R -U -D
3864: Retrieves the name and version of the underlying window system platform.
3865:
3866: @item @code{SIZE} +R -U -D
3867: Retrieves the display resolution of the specified graphical display. For instance, a 1080p display would have a @code{SIZE} value of @code{1920,1080}.
3868:
3869: @item @code{SPECTRUM} +R -U -D
3870: Retrieves the color depth (number of colors supported) of the specified graphical display.
3871:
3872: @item @code{COLORTYPE} +R -U -D
3873: Always returns @code{COLOR}, as monochrome and grayscale displays are not yet supported in FreeM.
3874:
3875: @item @code{UNITS} +R -U -D
3876: Returns the measurement unit of the specified display, i.e., @code{PIXEL}.
3877:
3878: @item @code{TYPEFACE} +R -U -D
3879: 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.
3880:
3881: @end table
3882:
3883: @node ^$EVENT
3884: @section ^$EVENT
3885: @cindex ^$EVENT
3886: @cindex structured system variables, ^$EVENT
3887:
3888: The @code{^$EVENT} SSVN is not yet implemented.
3889:
3890: @node ^$GLOBAL
3891: @section ^$GLOBAL
3892: @cindex ^$GLOBAL
3893: @cindex structured system variables, ^$GLOBAL
3894:
3895: The @code{^$GLOBAL} structured system variable provides information about M globals. The first-level subscript is a global name, sans the leading caret symbol.
3896:
3897: The following second-level subscripts are supported:
3898:
3899: @table @asis
3900:
3901: @item @code{BYTES} +R -U -D
3902: Returns the number of bytes this global occupies in fixed storage.
3903:
3904: @item @code{BLOCKS} +R -U -D
3905: Returns the number of blocks contained in this global.
3906:
3907: @item @code{BLOCKSIZE} +R -U -D
3908: Returns the size of data blocks for this global. Currently, FreeM only supports 1024-byte blocks.
3909:
3910: @item @code{FILE} +R -U -D
3911: Returns the full filesystem path to the data file where this global resides in fixed storage.
3912:
3913: @item @code{NAMESPACE} +R +U +D
3914: 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.
3915:
3916: @end table
3917:
3918: @node ^$JOB
3919: @section ^$JOB
3920: @cindex ^$JOB
3921: @cindex structured system variables, ^$JOB
3922:
3923: FreeM fully implements @code{^$JOB} per ANSI X11.1-1995, as well as several extensions proposed in the M Millennium Draft Standard.
3924:
3925: The first subscript of @code{^$JOB} represents the @code{$JOB} of the process.
3926:
3927: 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.
3928:
3929: The following subscripts are supported:
3930:
3931: @table @asis
3932:
3933: @item @code{GVNDEFAULT} +R +U +D
3934: Contains a default expression to be evaluated if a global variable access attempt results in an @code{M7} error.
3935:
3936: Equivalent to wrapping all global accesses in @code{$GET(@emph{global-name},@emph{string-expr})}.
3937:
3938: @item @code{LVNDEFAULT} +R +U +D
3939: Contains a default expression to be evaluated if a local variable access attempt results in an @code{M6} error.
3940:
3941: Equivalent to wrapping all local accesses in @code{$GET(@emph{global-name},@emph{string-expr})}.
3942:
3943: @item @code{LVNQOVAL} +R +U +D
3944: Contains the data value (if any) at the subscripted local variable reference from the most recent @code{$ORDER} or @code{$QUERY} operation.
3945:
3946: 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.
3947:
3948: @item @code{GVNQOVAL} +R +U +D
3949: Contains the data value (if any) at the subscripted global variable reference from the most recent @code{$ORDER} or @code{$QUERY} operation.
3950:
3951: 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.
3952:
3953: @item @code{ZCOMMANDS} +R +U -D
3954: 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.
3955:
3956: 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.
3957:
3958: If you remove a command from this list, you may provide your own private M implementation of the command in the manner described above.
3959:
3960: 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{%}.
3961:
3962: @item @code{PIPE_GLVN} +R +U -D
3963: 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{!>}.
3964:
3965: @item @code{ZCOMMAND_ARGUMENT_NAME} +R +U -D
3966: Returns or sets the variable name in which arguments to user-defined @code{Z}-commands are passed. Defaults to @code{%}.
3967:
3968: @item @code{ZFUNCTIONS} +R +U -D
3969: 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.
3970:
3971: 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.
3972:
3973: If you remove a function from this list, you may provide your own private M implementation of the function in the manner described above.
3974:
3975: @item @code{ZSVS} +R +U -D
3976: 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.
3977:
3978: 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.
3979:
3980: 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.
3981:
3982: @item @code{BREAK_HANDLER} +R +U -D
3983: Contains M code to be executed when the @code{BREAK} command is run.
3984:
3985: @item @code{ROUTINE_BUFFER_SIZE} +R +U -D
3986: 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.
3987:
3988: @item @code{ROUTINE_BUFFER_COUNT} +R +U -D
3989: 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.
3990:
3991: @item @code{ROUTINE_BUFFER_AUTO_ADJUST} +R +U -D
3992: 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.
3993:
3994: @item @code{SYMBOL_TABLE_SIZE} +R +U -D
3995: 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.
3996:
3997: @item @code{SYMBOL_TABLE_AUTO_ADJUST} +R +U -D
3998: 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.
3999:
4000:
4001: @item @code{USER_DEFINED_ISV_TABLE_SIZE} +R +U -D
4002: 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.
4003:
4004: @item @code{USER_DEFINED_ISV_TABLE_AUTO_ADJUST} +R +U -D
4005: 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.
4006:
4007: @item @code{GVN_UNIQUE_CHARS} +R +U -D
4008: Returns or sets the number of characters of a global name that make it unique, from 1 to 255.
4009:
4010: @item @code{GVN_CASE_SENSITIVE} +R +U -D
4011: 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.
4012:
4013: @item @code{GVN_NAME_SUB_LENGTH} +R +U -D
4014: Returns or sets the maximum number of characters of a global name plus all of its subscripts, from 1-255.
4015:
4016: @item @code{GVN_SUB_LENGTH} +R +U -D
4017: Returns or sets the maximum number of characters of a single global subscript, from 1-255.
4018:
4019: @item @code{SINGLE_USER} +R +U -D
1.27 snw 4020: 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 4021:
1.27 snw 4022: 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 4023:
4024: @item @code{CHARACTER} +R -U -D
4025: Returns the character set of the job.
4026:
4027: @item @code{CWD} +R +U -D
4028: Returns or sets the current working directory of the job.
4029:
4030: @item @code{OPEN} +R -U -D
4031: The @code{^$JOB($JOB,"OPEN",<channel>} subscripts list the open I/O channels in the specified job.
4032:
4033: @item @code{BERKELEYDB,FLUSH_THRESHOLD} +R +U -D
4034: 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.
4035:
4036: @item @code{EVENT} +R +U +D
4037: 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.
4038:
4039: @item @code{GLOBAL} +R -U -D
4040: Returns the global environment of the job.
4041:
4042: @item @code{IOPATH} +R +U -D
4043: Returns or sets the @emph{I/O path} to be used by the @code{OPEN} command.
4044:
4045: @item @code{PRIORITY} +R +U -D
4046: Returns or sets the @emph{nice} value of the FreeM job.
4047:
4048: @item @code{REVSTR} +R +U -D
4049: When set to 1, allows @code{$EXTRACT} to accept negative values.
4050:
4051: @item @code{ROUTINE} +R -U -D
4052: Returns the name of the routine currently being executed by the job.
4053:
4054: @item @code{SYMTAB} +R +U -D
4055: Returns or sets the current local variable symbol table in use.
4056:
4057: 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.
4058:
4059: 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")}.
4060:
4061: Setting this subscript to values other than @code{0} or @code{1} will result in a @code{ZINVEXPR} error.
4062:
4063: @item @code{$PDISPLAY} +R -U -D
4064: Returns the value of @code{$PDISPLAY} for the job.
4065:
4066: @item @code{$PRINCIPAL} +R -U -D
4067: Returns the value of @code{$PRINCIPAL} for the job.
4068:
4069: @item @code{$TLEVEL} +R -U -D
4070: Returns the current transaction level (value of @code{$TLEVEL} for the job.
4071:
4072: @item @code{$IO} +R -U -D
4073: Returns the current value of @code{$IO} for the job.
4074:
4075: @item @code{USER} +R -U -D
4076: Returns the UID of the user owning the job.
4077:
4078: @item @code{GROUP} +R -U -D
4079: Returns the GID of the group owning the job.
4080:
4081: @item @code{NAMESPACE} +R +U -D
4082: Returns or sets the name of the job's currently-active namespace.
4083:
4084: @item @code{MATH} +R +U -D
4085: 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.
4086:
4087: @code{IEEE754} mode will make mathematical calculations significantly faster, especially when accelerated by a floating-point processor, at the expense of precision and accuracy.
4088:
4089: @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.
4090:
4091: Attempting to @code{SET} this node to values other than @code{FIXED} or @code{IEEE754} will set @code{$ECODE} to @code{M29}.
4092:
4093: @end table
4094:
4095: @node ^$LOCK
4096: @section ^$LOCK
4097: @cindex ^$LOCK
4098: @cindex structured system variables, ^$LOCK
4099:
4100: 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.
4101:
4102: Attempting to @code{SET} or @code{KILL} any node in @code{^$LOCK} will raise error @code{M29}.
4103:
4104: @node ^$OBJECT
4105: @section ^$OBJECT
4106: @cindex ^$OBJECT
4107: @cindex structured system variables, ^$OBJECT
4108:
4109: @node ^$ROUTINE
4110: @section ^$ROUTINE
4111: @cindex ^$ROUTINE
4112: @cindex structured system variables, ^$ROUTINE
4113:
4114: The @code{^$ROUTINE} SSVN exposes a list of routines available in the current FreeM namespace, as well as additional attributes further describing each routine.
4115:
4116: The first-level subscript is the name of a FreeM routine minus the leading caret symbol.
4117:
4118: The following second-level subscripts are supported:
4119:
4120: @table @asis
4121:
4122: @item @code{CHARACTER} +R -U -D
4123: Returns the character set of the routine.
4124:
4125: @item @code{NAMESPACE} +R -U -D
4126: Returns the name of the FreeM namespace in which the routine resides.
4127:
4128: @item @code{PATH} +R -U -D
4129: Returns the full filesystem path to the routine in fixed storage.
4130:
4131: @end table
4132:
4133: @node ^$SYSTEM
4134: @section ^$SYSTEM
4135: @cindex ^$SYSTEM
4136: @cindex structured system variables, ^$SYSTEM
4137:
4138: The @code{^$SYSTEM} SSVN exposes system-level implementation details.
4139:
4140: The following first-level subscripts are supported:
4141:
4142: @table @asis
4143:
4144: @item @code{DEFPSIZE} +R -U -D
4145: Returns the default size in bytes of the symbol table and routine buffer memory partition.
4146:
4147: @item @code{DEFUDFSVSIZ} +R -U -D
4148: Returns the default size in bytes of the user-defined intrinsic special variable table.
4149:
4150: @item @code{DEFNSIZE} +R -U -D
4151: Returns the default size of the @code{NEW} stack, in number of entries.
4152:
4153: @item @code{MAXNO_OF_RBUF} +R -U -D
4154: Returns the maximum number of routine buffers.
4155:
4156: @item @code{DEFNO_OF_RBUF} +R -U -D
4157: Returns the default number of routine buffers.
4158:
4159: @item @code{DEFPSIZE0} +R -U -D
4160: Returns the default size in bytes of each routine buffer.
4161:
4162: @item @code{NO_GLOBLS} +R -U -D
4163: Returns the maximum number of globals that can be concurrently opened.
4164:
4165: @item @code{NO_OF_GBUF} +R -U -D
4166: Returns the number of global buffers.
4167:
4168: @item @code{NESTLEVLS} +R -U -D
4169: Returns the depth of the @code{DO}, @code{FOR}, @code{XECUTE} stack.
4170:
4171: @item @code{PARDEPTH} +R -U -D
4172: Returns the maximum depth of the parser's parameter stack.
4173:
4174: @item @code{PATDEPTH} +R -U -D
4175: Returns the maximum number of @emph{patatom}s in each pattern.
4176:
4177: @item @code{TRLIM} +R -U -D
4178: Returns the trace limit of the @code{BUILTIN} global handler.
4179:
4180: @item @code{ARGS_IN_ESC} +R -U -D
4181: Returns the maximum number of arguments in a terminal escape sequence.
4182:
4183: @item @code{ZTLEN} +R -U -D
4184: Returns the maximum length of @code{$ZTRAP}.
4185:
4186: @item @code{FUNLEN} +R -U -D
4187: Returns the maximum length of the @code{$ZF} (function key) variable.
4188:
4189: @item @code{NAME_LENGTH} +R -U -D
4190: Returns the maximum length of variable names in the current FreeM build. Compatible with the same SSVN node in @emph{Reference Standard M}
4191:
4192: @item @code{STRING_MAX} +R -U -D
4193: Returns the maximum length of character strings in the current FreeM build. Compatible with the same SSVN node in @emph{Reference Standard M}
4194:
4195: @item @code{$NEXTOK} +R -U -D
4196: 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}.
4197:
4198: @item @code{EOK} +R -U -D
4199: 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}.
4200:
4201: @item @code{OFFOK} +R -U -D
4202: 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}.
4203:
4204: @item @code{BIG_ENDIAN} +R -U -D
4205: 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}.
4206:
4207: @item @code{NAMESPACE} +R -U -D
4208: The descendant subscripts of this node list each namespace in the current FreeM environment.
4209:
4210: @item @code{MAPPINGS,GLOBAL} +R -U -D
4211: Descendant subscripts of this node represent global name mappings set in @code{^$GLOBAL(@emph{gvn},"NAMESPACE")}
4212:
4213: @end table
4214:
4215: @node ^$WINDOW
4216: @section ^$WINDOW
4217: @cindex ^$WINDOW
4218: @cindex structured system variables, ^$WINDOW
4219:
4220: 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.
4221:
4222: @node ^$ZPROCESS
4223: @section ^$ZPROCESS
4224: @cindex ^$ZPROCESS
4225: @cindex structured system variables, ^$ZPROCESS
4226:
4227: 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.
4228:
4229: The first subscript always represents the @emph{process ID} of the external process being acted upon.
4230:
4231: The following values for the second subscript are supported:
4232:
4233:
4234: @table @asis
4235:
4236: @item @code{EXISTS} +R -U -D
4237: Returns 1 if the referenced process exists; 0 otherwise.
4238:
4239: @item @code{ATTRIBUTE} +R -U -D
4240: 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.
4241:
4242: @item @code{SIGNAL} -R +U -D
4243: 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}.
4244:
4245: 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.
4246:
4247: @end table
4248:
4249: @node ^$ZRPI
4250: @section ^$ZRPI
4251: @cindex ^$ZRPI
4252: @cindex structured system variables, ^$ZRPI
4253:
4254: The @code{^$ZRPI} structured system variable provides easy access to general-purpose input/output (GPIO) pins on Raspberry Pi single-board computers.
4255:
4256: To initialize the GPIO subsystem, @code{SET ^$ZRPI("INITIALIZE")=1}.
4257:
4258: 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:
4259:
4260: @table @asis
4261:
4262: @item @code{MODE} +R +U -D
4263: Represents the operating mode of the selected pin. One of @code{INPUT}, @code{OUTPUT}, @code{PWM_OUTPUT}, or @code{GPIO_CLOCK}.
4264:
4265: @item @code{DIGITAL} +R +U -D
4266: Reads or writes the selected pin digitally. The value is limited to @code{1} or @code{0}.
4267:
4268: @item @code{ANALOG} +R +U -D
4269: Reads or writes the selected pin in an analog fashion. The value represents analog voltage.
4270:
4271: @end table
4272:
4273: @node Operators
4274: @chapter Operators
4275:
4276: @menu
4277: * Unary +:: Force a value to positive.
4278: * Unary -:: Force a value to negative.
4279: * +:: Add.
4280: * +=:: Add and assign.
4281: * ++:: Postfix increment.
4282: * -:: Subtract.
4283: * -=:: Subtract and assign.
4284: * --:: Postfix decrement.
4285: * *:: Multiply.
4286: * *=:: Multiply and assign.
4287: * /:: Divide.
4288: * /=:: Divide and assign.
4289: * \:: Integer divide.
4290: * \=:: Integer divide and assign.
4291: * #:: Modulo.
4292: * #=:: Modulo and assign.
4293: * **:: Exponentiate.
4294: * **=:: Exponentiate and assign.
4295: * <:: Less than.
4296: * <=:: Less than or equal to.
4297: * >:: Greater than.
4298: * >=:: Greater than or equal to.
4299: * _:: Concatenate.
4300: * _=:: Concatenate and assign.
4301: * =:: Equals.
4302: * [:: Contains.
4303: * ]:: Follows.
4304: * ]]:: Sorts after.
4305: * ?:: Pattern match.
4306: * &:: Logical AND.
4307: * ! (Operator):: Logical OR.
4308: * ':: Logical NOT.
4309: * @@ (Operator):: Indirect
4310: @end menu
4311:
4312: @node Unary +
4313: @section Unary +
4314: @cindex operators, unary +
4315:
4316: Forces a number to positive, whether positive or negative. Also forces numeric coercion of strings.
4317:
4318: @node Unary -
4319: @section Unary -
4320: @cindex operators, unary -
4321:
1.28 snw 4322: Forces a number to negative, whether positive or negative. Also forces numeric coercion of strings.
4323:
1.1 snw 4324: @node +
4325: @section + (Add)
4326: @cindex operators, +
4327:
1.28 snw 4328: @emph{Syntax}
4329:
4330: @example
4331: S X=1+2 ; => 3
4332: @end example
4333:
4334: Adds numbers together.
4335:
1.1 snw 4336: @node +=
4337: @section += (Add/Assign)
4338: @cindex operators, +=
4339:
1.28 snw 4340: @emph{Syntax}
4341:
4342: @example
4343: S X=5
4344: S X+=3 ; => 8
4345: @end example
4346:
4347: Increments the variable on the LHS by the value on the RHS.
4348:
1.1 snw 4349: @node ++
4350: @section ++ (Postfix Increment)
4351: @cindex operators, ++
4352:
1.28 snw 4353: Increments a variable by 1.
4354:
1.1 snw 4355: @node -
4356: @section - (Subtract)
4357: @cindex operators, -
4358:
1.28 snw 4359: Subtracts one number from another.
4360:
1.1 snw 4361: @node -=
4362: @section -= (Subtract/Assign)
4363: @cindex operators, -=
4364:
1.28 snw 4365: @emph{Syntax}
4366:
4367: @example
4368: S X=5
4369: S X-=3 ; => 2
4370: @end example
4371:
4372: Decrements the variable on the LHS by the value on the RHS.
4373:
1.1 snw 4374: @node --
4375: @section -- (Postfix Decrement)
4376: @cindex operators, --
4377:
1.28 snw 4378: Decrements the variable by one.
4379:
1.1 snw 4380: @node *
4381: @section * (Multiply)
4382: @cindex operators, *
4383:
1.28 snw 4384: Multiplies one number by another.
4385:
1.1 snw 4386: @node *=
4387: @section *= (Multiply/Assign)
4388: @cindex operators, *=
4389:
1.28 snw 4390:
4391:
1.1 snw 4392: @node /
4393: @section / (Divide)
4394: @cindex operators, /
4395:
4396: @node /=
4397: @section /= (Divide/Assign)
4398: @cindex operators, /=
4399:
4400: @node \
4401: @section \ (Integer Divide)
4402: @cindex operators, \
4403:
4404: @node \=
4405: @section \= (Integer Divide/Assign)
4406: @cindex operators, \=
4407:
4408: @node #
4409: @section # (Modulo)
4410: @cindex operators, #
4411:
4412: @node #=
4413: @section #= (Modulo/Assign)
4414: @cindex operators, #=
4415:
4416: @node **
4417: @section ** (Exponentiate)
4418: @cindex operators, **
4419:
4420: @node **=
4421: @section **= (Exponentiate/Assign)
4422: @cindex operators, **=
4423:
4424: @node <
4425: @section < (Less Than)
4426: @cindex operators, <
4427:
4428: @node <=
4429: @section <= (Less Than or Equal To)
4430: @cindex operators, <=
4431:
4432: @node >
4433: @section > (Greater Than)
4434: @cindex operators, >
4435:
4436: @node >=
4437: @section >= (Greater Than or Equal To)
4438: @cindex operators, >=
4439:
4440: @node _
4441: @section _ (Concatenate)
4442: @cindex operators, _
4443:
4444: @node _=
4445: @section _= (Concatenate/Assign)
4446: @cindex operators, _=
4447:
4448: @node =
4449: @section = (Equals)
4450: @cindex operators, =
4451:
4452: @node [
4453: @section [ (Contains)
4454: @cindex operators, [
4455:
4456: @node ]
4457: @section ] (Follows)
4458: @cindex operators, ]
4459:
4460: @node ]]
4461: @section ]] (Sorts After)
4462: @cindex operators, ]]
4463:
4464: @node ?
4465: @section ? (Pattern Match)
4466: @cindex operators, ?
4467:
4468: @node &
4469: @section & (Logical AND)
4470: @cindex operators, &
4471:
4472: @node ! (Operator)
4473: @section ! (Logical OR)
4474: @cindex operators, !
4475:
4476: @node '
4477: @section ' (Logical NOT)
4478: @cindex operators, '
4479:
4480: @node @@ (Operator)
4481: @section @@ (Indirect)
4482: @cindex operators, @@
4483:
4484: @node Routines
4485: @chapter Routines
4486: @cindex routines
4487:
4488: A @emph{routine} is a file containing M source code to be processed by FreeM.
4489:
4490: 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}).
4491:
4492: @menu
4493: * Routine Naming:: Requirements and conventions for routine names.
4494: @end menu
4495:
4496:
4497: @node Routine Naming
4498: @section Routine Naming
4499: 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.
4500:
4501: Routine naming rules are as follows:
4502:
4503: @itemize @bullet
4504: @item Routine names must begin with an upper- or lower-case letter, or a @code{%} sign
4505: @item Within the routine name, you may have upper-case or lower-case letters or digits
4506: @item The entire routine name must not be longer than 255 characters
4507: @end itemize
4508:
4509: Routines whose names begin with @code{%} must be located in the @code{SYSTEM} namespace. Other routines may be located in any namespace.
4510:
4511: @node Types
4512: @chapter Types
4513: @cindex types
4514: @cindex data types
4515:
4516: 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.
4517:
4518: @menu
4519: * BOOLEAN:: Truth values.
4520: * COMPLEX:: Numbers with real and imaginary parts.
4521: * INTEGER:: Numbers with no decimal part.
4522: * REAL:: Numbers with a decimal part.
4523: * STRING:: Arbitrary strings of characters.
4524: * Custom Types (Classes):: User-defined, object-oriented types.
4525: @end menu
4526:
4527: @node BOOLEAN
4528: @section BOOLEAN
4529: @cindex data types, BOOLEAN
4530: @cindex types, BOOLEAN
4531:
4532: The @code{BOOLEAN} type represents any M value that can be interpreted as a truth-value.
4533:
4534: @node COMPLEX
4535: @section COMPLEX
4536: @cindex data types, COMPLEX
4537: @cindex types, COMPLEX
4538:
4539: 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.
4540:
4541: 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}.
4542:
4543: @node INTEGER
4544: @section INTEGER
4545: @cindex data types, INTEGER
4546: @cindex types, INTEGER
4547:
4548: An @code{INTEGER} is an interpretation of numeric data with any fractional part removed.
4549:
4550: @node REAL
4551: @section REAL
4552: @cindex data types, REAL
4553: @cindex types, REAL
4554:
1.29 snw 4555: A @code{REAL} is a numeric interpretation of data including a fractional part.
4556:
1.1 snw 4557: @node STRING
4558: @section STRING
4559: @cindex data types, STRING
4560: @cindex types, STRING
4561:
1.36 snw 4562: The @code{STRING} is the fundamental FreeM data type. Other types are inferred from the context of their usage.
4563:
4564: @subsection String Rules
4565:
4566: The following rules apply to all FreeM strings:
4567:
4568: @itemize
4569: @item Must not exceed 255 characters
4570: @item Must not contain @code{$C(0)}, @code{$C(201)}, or @code{$C(202)}
4571: @end itemize
4572:
4573: @subsection String Quoting Rules
4574: Strings in FreeM must be surrounded in double quotes:
4575:
4576: @example
4577: SET MYSTRING="This is a string literal"
4578: @end example
4579:
4580: If you want to include double quotes inside of a string, simply double them:
4581:
4582: @example
4583: SET MYSTRING="This is a ""string literal"" with embedded double quotes"
4584: @end example
4585:
1.29 snw 4586:
1.1 snw 4587: @node Custom Types (Classes)
4588: @section Custom Types (Classes)
4589: @cindex data types, custom
4590: @cindex types, custom
4591: @cindex classes
4592:
4593: See @ref{Classes}.
4594:
4595: @node Globals
4596: @chapter Globals
4597: @cindex globals
4598: @cindex variables, global
4599: @cindex data
4600:
1.33 snw 4601: @menu
4602: * Globals Overview:: Basics of FreeM persistent storage.
4603: * Creating Globals:: How to create globals.
4604: * Removing Globals:: How to remove globals.
4605: * Global Storage:: How globals are stored.
4606: @end menu
4607:
4608: @node Globals Overview
4609: @section Globals Overview
4610:
1.31 snw 4611: 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.
4612:
4613: Each global comprises three elements:
4614:
4615: @itemize @bullet
4616: @item
4617: An alphabetic name beginning with a caret (@code{^}) or a caret and a percent sign (@code{^%})
4618: @item
4619: Optionally, one or more comma-delimited subscripts, enclosed in parentheses
4620: @item
4621: A value of up to 255 characters in length
4622: @end itemize
4623:
1.36 snw 4624: 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 4625:
4626: @node Creating Globals
4627: @section Creating Globals
4628: @cindex globals, creating
4629:
4630: To create a global, you can use the @code{SET} command:
4631:
4632: @example
4633: SET ^MYGLOBAL("foo","bar")="this is the data value"
4634: @end example
4635:
4636: @node Removing Globals
4637: @section Removing Globals
4638: @cindex globals, removing
4639:
4640: To remove an entire global, you can use the @code{KILL} command with the unsubscripted name of the global:
4641:
4642: @example
4643: KILL ^MYGLOBAL
4644: @end example
4645:
4646: 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:
4647:
4648: @example
4649: KILL ^MYGLOBAL("foo")
4650: @end example
4651:
4652: This will remove only the @code{"foo"} subscript and all of its children.
4653:
4654: If you only want to remove the data value at a specific subscript level, leaving the subscript itself intact, use @code{KVALUE}:
4655:
4656: @example
4657: KVALUE ^MYGLOBAL("foo")
4658: @end example
4659:
4660: @node Global Storage
4661: @section Global Storage
4662: @cindex globals, storage
4663:
4664: FreeM globals are stored in @code{$PREFIX/var/freem/@emph{<environment-name>}/@emph{<namespace-name>}/globals} in a binary format.
4665:
4666: Global files have a header of the following format:
4667:
4668: @verbatim
4669: typedef struct global_header {
4670:
4671: char magic[5]; /* FRMGL */
4672: int format_version;
4673: char host_triplet[40];
4674: char host_id[256];
4675:
4676: unsigned long block_size;
4677: unsigned long last_transaction_id;
4678:
4679: long created;
4680: long last_backup;
4681:
4682: } global_header;
4683: @end verbatim
4684:
1.1 snw 4685: @node Concurrency Control
4686: @chapter Concurrency Control
4687: @cindex concurrency control
4688: @cindex locking
4689: @cindex transaction processing
4690:
1.33 snw 4691: @menu
4692: * Concurrency Control Overview:: Basics of concurrency control.
4693: * Advisory Locks:: Coordinating access voluntarily.
4694: * Transaction Processing:: Ensuring logical consistency.
4695: @end menu
4696:
4697: @node Concurrency Control Overview
4698: @section Concurrency Control Overview
4699:
1.34 snw 4700: 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 4701:
1.34 snw 4702: In FreeM, there are two mechanisms provided for managing concurrent global access: @emph{advisory locks}, and @emph{transaction processing}.
4703:
4704: 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.
4705:
4706: 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 4707:
1.33 snw 4708: @node Advisory Locks
4709: @section Advisory Locks
4710:
1.31 snw 4711: @node Transaction Processing
4712: @section Transaction Processing
4713: @cindex transaction processing
4714:
1.39 snw 4715: 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 4716:
4717: @subsection Theory of Operation
4718:
4719: 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.
4720:
4721: 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.
4722:
4723: 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.
4724:
4725: Checkpoints can have one of two modes:
4726:
4727: @table @asis
4728:
4729: @item @code{CP_REMOVE}
4730: 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.
4731:
4732: @item @code{CP_RESTORE}
4733: 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.
4734:
4735: @end table
4736:
4737: The below example shows a few global operations and checkpoints for a transaction in-flight using the @code{trantab} direct-mode command:
4738:
4739: @verbatim
4740: TL1:DEFAULT.USER> trantab
4741: $TLEVEL 1*
4742: Operations for Transaction ID: 6ea14aad-b8f1-47f9-9f52-4f513f892bc0 [RESTARTABLE SERIAL]
4743:
4744: OP. NO. ACTION KEY/DATA
4745: ------- ------ --------
4746: 1 SET ^FOO=3
4747: 2 KILL ^FOO
4748: 3 SET ^snw=10
4749: 4 SET ^BRANDNEW=6
4750:
4751: Global checkpoints:
4752:
4753: GLOBAL MODE FILES
4754: ------ ---- -----
4755: ^BRANDNEW CP_REMOVE IN: /usr/local/var/freem/USER/globals/^BRANDNEW
4756: ^snw CP_RESTORE IN: /usr/local/var/freem/USER/globals/^snw
4757: OUT: /usr/local/var/freem/USER/globals/^snw.23390.1.chk
4758: ^FOO CP_RESTORE IN: /usr/local/var/freem/USER/globals/^FOO
4759: OUT: /usr/local/var/freem/USER/globals/^FOO.23390.1.chk
4760: @end verbatim
4761:
4762: 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.
4763:
4764: @subsection Using Transaction Processing
4765:
4766: To use transactions in FreeM, you need to be familiar with three commands:
4767:
4768: @itemize @bullet
4769: @item
4770: @code{TSTART}
4771: @item
4772: @code{TCOMMIT}
4773: @item
4774: @code{TROLLBACK}
4775: @end itemize
4776:
4777: With transaction processing, global variable operations occurring between @code{TSTART} and @code{TCOMMIT} commands will be contained within the transaction.
4778:
4779: The atomicity, consistency, isolation, and durability facets of FreeM transaction hinge on the transaction mode.
4780:
4781: @subsubsection BATCH Transactions
4782: @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.
4783:
4784: 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.
4785:
4786: @subsubsection SERIAL Transactions
4787: @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).
4788:
1.1 snw 4789: @node Local Variables
4790: @chapter Local Variables
4791: @cindex variables, local
4792: @cindex local variables
4793:
1.41 snw 4794: @menu
4795: * Local Variables Overview:: The basics of locals.
4796: * Creating Local Variables:: Creating locals with SET.
4797: * Removing Local Variables:: Removing locals with KILL.
4798: @end menu
4799:
4800: @node Local Variables Overview
1.38 snw 4801: @section Local Variables Overview
4802:
4803: FreeM @emph{local variables} have the same data structure as global variables, but are scoped to a single FreeM process, and stored in memory.
4804:
4805: Each local comprises three elements:
4806:
4807: @itemize @bullet
4808: @item
4809: An alphabetic name beginning with a letter or a percent sign (@code{%})
4810: @item
4811: Optionally, one or more comma-delimited subscripts, enclosed in parentheses
4812: @item
4813: A value of up to 255 characters in length
4814: @end itemize
4815:
4816: @node Creating Local Variables
4817: @section Creating Local Variables
4818: @cindex local variables, creating
4819:
4820: To create a local variable, use the @code{SET} command:
4821:
4822: @example
4823: SET MYLOCAL("foo","bar")="this is the data value"
4824: @end example
4825:
4826: @node Removing Local Variables
4827: @section Removing Local Variables
4828: @cindex local variables, removing
4829:
4830: To remove an entire local variable, you can use the @code{KILL} command with the unsubscripted name of the variable:
4831:
4832: @example
4833: KILL MYLOCAL
4834: @end example
4835:
4836: 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:
4837:
4838: @example
4839: KILL MYLOCAL("foo")
4840: @end example
4841:
4842: This will remove only the @code{"foo"} subscript and all of its children.
4843:
4844: If you only want to remove the data value at a specific subscript level, leaving the subscript itself intact, use @code{KVALUE}:
4845:
4846: @example
4847: KVALUE MYLOCAL("foo")
4848: @end example
4849:
1.1 snw 4850: @node Scoping
4851: @chapter Scoping
4852: @cindex scoping
4853:
1.38 snw 4854: 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.
4855:
4856: 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.
4857:
1.39 snw 4858: @emph{Example}
4859:
4860: @example
4861: MYRTN ;
4862: S J=1 ; set local variable J to 1
4863: W J,! ; this will output "1"
4864: D X ; execute subroutine X
4865: W J,! ; this will output "1", as the value of J was restored
4866: Q
4867: ;;
4868: X ;
4869: N J ; stack J
4870: S J=6 ; set its value to 6
4871: W J,! ; this will output "6"
4872: Q ; quit from the subroutine, destroying its stack frame
4873: ;;
4874: @end example
4875:
4876: @section Scoping Considerations for $TEST
4877:
4878: 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.
4879:
4880: 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.
4881:
4882: When writing new M code in FreeM, we strongly suggest using @code{THEN} as follows:
4883:
4884: @example
4885: MYRTN ;
4886: IF MYVAR=1 THEN DO SUBRT
4887: @end example
4888:
4889: This is instead of the traditional form:
4890:
4891: @example
4892: MYRTN ;
4893: IF MYVAR=1 DO SUBR
4894: @end example
4895:
4896: @cartouche
4897: @quotation
1.40 snw 4898: @emph{Style Recommendation}
1.39 snw 4899:
4900: 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.
4901:
4902: 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.
4903: @end quotation
4904: @end cartouche
4905:
1.1 snw 4906: @node Decision Constructs
4907: @chapter Decision Constructs
4908: @cindex decision constructs
4909: @cindex IF
4910: @cindex ELSE
4911: @cindex THEN
4912: @cindex postconditionals
4913:
4914: @node Branch Constructs
4915: @chapter Branch Constructs
4916: @cindex branch constructs
4917: @cindex DO
4918: @cindex GOTO
4919: @cindex JOB
4920:
4921: @node Loop Constructs
4922: @chapter Loop Constructs
4923: @cindex loop constructs
4924: @cindex FOR
4925:
4926: @node Modular Programming
4927: @chapter Modular Programming
4928: @cindex modular programming
4929: @cindex functions, extrinsic
4930: @cindex subroutines
4931:
1.2 snw 4932: @menu
4933: * Subroutines:: Making sections of code reusable.
4934: * Extrinsic Functions:: Reusable code that returns a value.
4935: @end menu
4936:
1.1 snw 4937: @node Subroutines
4938: @section Subroutines
4939:
4940: @node Extrinsic Functions
4941: @section Extrinsic Functions
4942:
4943: @node Object-Oriented Programming
4944: @chapter Object-Oriented Programming
4945: @cindex object-oriented programming
4946: @cindex programming, object-oriented
4947:
1.2 snw 4948:
1.1 snw 4949: @node Classes
4950: @section Classes
4951:
1.33 snw 4952:
4953: @node Class Overview
4954: @subsection Class Overview
4955:
1.29 snw 4956: 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:
4957:
4958: @example
4959: MYCLASS(THIS,INIT):OBJECT ; Constructor for MYCLASS, inherits OBJECT
4960: ; two private variables
4961: S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
4962: S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
4963: Q
4964: ;
4965: DESTROY(THIS) ; This is the destructor
4966: Q
4967: @end example
4968:
4969: The above example demonstrates general class syntax.
4970:
4971: @node Constructors
4972: @subsection Constructors
4973:
4974: A @emph{constructor} is an M entry point that is called when a new instance of a class is created.
4975:
4976: 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}.
4977:
4978: @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.
4979:
4980: A constructor looks like this:
4981:
4982: @example
4983: %FRACTION(THIS,INIT):OBJECT ;
4984: S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
4985: S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
4986: Q
4987: @end example
4988:
4989: @emph{Syntax}
4990: @example
4991: @emph{<class-name>}(THIS,INIT)[:@emph{<superclass>}]
4992: @end example
4993:
4994: 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}.
4995:
4996: @node Destructors
4997: @subsection Destructors
4998: 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}).
4999:
5000: The destructor should be used to clean up any resources used by class methods.
5001:
5002: A destructor looks like this:
5003:
5004: @example
5005: DESTROY(THIS) ;
5006: ; free any resources that should be freed at the end of the object's lifetime
5007: Q
5008: @end example
1.2 snw 5009:
1.1 snw 5010: @node Inheritance
1.29 snw 5011: @section Inheritance
5012:
5013: Every class you create will automatically inherit the methods and functionality of the @code{OBJECT} class, supplied with FreeM.
5014:
5015: 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.
5016:
5017: Inheritance is achieved by specifying the name of the superclass in the constructor:
5018:
5019: @example
5020: CLASS(THIS,INIT):SUPERCLASS
5021: @end example
5022:
5023: @node Runtime Polymorphism
5024: @subsection Runtime Polymorphism
5025:
5026: 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.
5027:
5028: 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 5029:
5030: @node Methods
1.29 snw 5031: @section Methods
5032: 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 5033:
1.29 snw 5034: The following class (@code{MYCLASS}) has a constructor, a destructor, and a method called @code{MYMETHOD}:
5035:
5036: @example
5037: %MYCLASS(THIS,INIT) ;
5038: Q THIS
5039: DESTROY(THIS) ;
5040: Q
5041: MYMETHOD(THIS) ;
5042: Q "VALUE"
5043: @end example
5044:
1.31 snw 5045: The dot operator is used to invoke class methods:
5046:
5047: @example
5048: DEFAULT.USER> N MYOBJ=$#^%MYCLASS("")
5049: DEFAULT.USER> W MYOBJ.MYMETHOD()
5050: VALUE
5051: @end example
5052:
1.29 snw 5053: @node Public and Private Variables
5054: @section Public and Private Variables
5055:
1.30 snw 5056: 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 5057:
5058: The below constructor for a @code{FRACTION} class defines two private fields:
5059:
5060: @example
5061: %FRACTION(THIS,INIT):OBJECT ;
5062: S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
5063: S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
5064: Q
5065: @end example
5066:
5067: Either of the following commands will create a public field:
5068:
5069: @example
5070: S THIS("VARNAM")="Initial Value"
5071: S THIS("VARNAM"):PUBLIC="Initial Value"
5072: @end example
1.1 snw 5073:
1.29 snw 5074: Attempting to access private fields from outside of the class will raise error condition @code{ZOBJFLDACCV}.
1.1 snw 5075:
1.31 snw 5076: @node Instantiating Objects
5077: @section Instantiating Objects
5078:
5079: To instantiate an object (i.e., create an object from a certain class), you will use the @code{NEW} command as follows:
5080:
5081: @example
5082: NEW MYSTR=$#^%STRING("myString")
5083: @end example
5084:
5085: This will create a local variable called MYSTR of type STRING, and initialize it with the value myString.
5086:
5087: @node Determining Object Class
5088: @section Determining Object Class
5089:
5090: To determine the class of any FreeM local variable, you will use the @code{$$TYPE()} method:
5091:
5092: @example
5093: USER> W MYSTR.$$TYPE()
5094: ^%STRING
5095: @end example
5096:
5097: The @code{$$TYPE()} method is a member of the @code{OBJECT} class.
5098:
1.1 snw 5099: @node Libraries
5100: @chapter Libraries
5101: @cindex libraries
5102:
5103: @node Sequential I/O
5104: @chapter Sequential I/O
5105:
5106: @node Network I/O
5107: @chapter Network I/O
5108: @cindex networks, input and output
5109:
5110: 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.
5111:
5112: @section Opening and Connecting a Client Socket
5113: @cindex networks, opening and connecting client sockets
5114:
5115: To open a client socket and connect to it, you will need to call the @code{OPEN} command and the @code{USE} command:
5116:
5117: @example
5118: ;
5119: ; Set socket read terminator to LF
5120: ;
5121: SET ^$DEVICE(100,"OPTIONS","TERMINATOR")=$C(10)
5122: ;
5123: ; Open an IPv4 TCP socket to mail.mydomain.com on port 25 (SMTP)
5124: ; and connect to it
5125: ;
5126: OPEN 100:"mail.mydomain.com:25:IPV4:TCP"
5127: USE 100:/CONNECT
5128: ;
5129: ; Read a line of input from the remote host and write it to the terminal
5130: ;
5131: NEW LINE
5132: READ LINE
5133: USE 0
5134: WRITE LINE,!
5135: ;
5136: ; CLOSE the socket and disconnect
5137: ;
5138: CLOSE 100
5139: QUIT
5140: @end example
5141:
5142: @node Extended Global References
5143: @chapter Extended Global References
5144: @cindex global references, extended
5145: @cindex extended global references
5146:
5147: @section Standard Extended Global References
5148: @cindex extended global references, standard
5149:
5150: 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.
5151:
5152: 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:
5153:
5154: @example
5155: WRITE ^|"VISTA"|VA(200,0),!
5156: @end example
5157:
5158: You may also use an expression that resolves to a string containing a valid namespace name:
5159:
5160: @example
5161: SET NS="VISTA"
5162: WRITE ^|NS|VA(200,0),!
5163: @end example
5164:
5165: @node Global Aliasing
5166: @chapter Global Aliasing
5167: @cindex aliasing, global
5168: @cindex globals, aliasing
5169:
5170: FreeM provides the ability to set alternative names for M global variables.
5171:
5172: To create an alias of @code{^FOO} named @code{^BAR}, use the following command:
5173:
5174: @example
5175: SET ^$JOB($JOB,"ALIASES","^BAR")="^FOO"
5176: @end example
5177:
5178: 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.
5179:
5180: @node Global Mappings
5181: @chapter Global Mappings
5182: @cindex mappings, global
5183: @cindex globals, mapping
5184:
5185: 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.
5186:
5187: To map the @code{^FOO} global to the @code{SYSTEM} namespace, any of the following will work:
5188:
5189: @example
5190: MAP GLOBAL ^FOO="SYSTEM"
5191: SET ^$GLOBAL("FOO","NAMESPACE")="SYSTEM"
5192: SET ^$SYSTEM("MAPPINGS","GLOBAL","^FOO")="SYSTEM"
5193: @end example
5194:
5195: There is no functional difference in any of the three approaches; the method you choose is a matter of personal preference.
5196:
5197: To remove the above mapping, any of the following examples will also work:
5198:
5199: @example
5200: UNMAP GLOBAL ^FOO
5201: KILL ^$GLOBAL("FOO","NAMESPACE")
5202: KILL ^$SYSTEM("MAPPINGS","GLOBAL","^FOO")
5203: @end example
5204:
5205:
5206:
5207: @node Asynchronous Event Handling
5208: @chapter Asynchronous Event Handling
5209: @cindex event handling, asynchronous
5210:
5211: Asynchronous event handling in FreeM follows the specifications of the unpublished MDC @emph{Millennium Draft Standard}.
5212:
5213: @section Setting Up Async Event Handlers
5214:
5215: 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:
5216:
5217: @table @emph
5218:
5219: @item Event Classes
5220: @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.
5221:
5222: @item Event Identifiers
5223: @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}).
5224:
5225: @item Event Handlers
5226: @emph{Event handlers} are M routines or subroutines that can be registered to run when an event of a certain event class occurs.
5227:
5228: @item Event Registration
5229: @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.
5230:
5231: @item Event Blocking and Unblocking
5232: @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.
5233:
5234: @end table
5235:
5236: The following sections of this chapter will take you step-by-step through setting up an event handler for @code{SIGWINCH} signal handling.
5237:
5238: @section Registering an Asynchronous Event Handler
5239: @cindex event handlers, registration
5240:
5241: To register a job-specific event handler that will only execute in the current FreeM process, use the following syntax:
5242:
5243: @example
5244: SET ^$JOB($JOB,"EVENT",@emph{event-class},@emph{event-identifier})=@emph{entryref}
5245: @end example
5246:
5247: To register a system-wide event handler that will execute in every FreeM process, use the following syntax:
5248:
5249: @example
5250: SET ^$SYSTEM("EVENT",@emph{event-class},@emph{event-identifier})=@emph{entryref}
5251: @end example
5252:
5253: For example, use the following to register @code{^RESIZE} as an asynchronous event handler for @code{SIGWINCH} events:
5254:
5255: @example
5256: SET ^$JOB($JOB,"EVENT","INTERRUPT","SIGWINCH")="^RESIZE"
5257: @end example
5258:
5259: This by itself will not enable asynchronous event handling, as it merely @emph{registers} an event handler, associating it with event class @code{INTERRUPT} and event identifier @code{SIGWINCH}.
5260:
5261: @section Enabling Asynchronous Event Handling
5262: @cindex event handlers, enabling
5263:
5264: In order to enable asyncronous event handling, the @code{ASTART} command is used. In the following example, we will enable asynchronous event handling for the @code{INTERRUPT} event class:
5265:
5266: @example
5267: ASTART "INTERRUPT"
5268: @end example
5269:
5270: Omitting the @code{"INTERRUPT"} argument will enable asynchronous event handling for @emph{all} event classes. See @code{ASTART} in the commands section for more details.
5271:
5272: Once this is done, any event handlers registered for the @code{INTERRUPT} event class in @code{^$JOB} will be executed asynchronously as appropriate.
5273:
5274: 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.
5275:
5276: @section Disabling Asynchronous Event Handling
5277: @cindex event handlers, disabling
5278:
5279: 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:
5280:
5281: @example
5282: ASTOP "INTERRUPT"
5283: @end example
5284:
5285: 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.
5286:
5287: You may also disable asynchronous event handling for a specific event identifier by @code{KILL}ing the appropriate node in the @code{^$JOB} SSVN, which unregisters the event handler altogether. The following example will unregister the event handler for the @code{SIGWINCH} event identifier:
5288:
5289: @example
5290: KILL ^$JOB($JOB,"EVENT","INTERRUPT","SIGWINCH")
5291: @end example
5292:
5293: @section Temporarily Blocking Asynchronous Event Handling
5294: @cindex event handlers, blocking
5295:
5296: 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.
5297:
5298: The following example blocks asynchronous event handling for the @code{INTERRUPT} event class:
5299:
5300: @example
5301: ABLOCK "INTERRUPT"
5302: @end example
5303:
5304: 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.
5305:
5306: 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.
5307:
5308: @node Global Triggers
5309: @chapter Global Triggers
5310: @cindex global triggers
5311: @cindex triggers
5312:
5313: 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.
5314:
5315: 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:
5316:
5317: @table @asis
5318:
5319: @item @code{DATA}
5320: Trigger will fire when the @code{$DATA} intrinsic function is called on @emph{<gvn>}.
5321:
5322: @item @code{GET}
5323: Trigger will fire when @emph{<gvn>} is read from.
5324:
5325: @item @code{INCREMENT}
5326: Trigger will fire when intrinsic function @code{$INCREMENT} is called on @emph{<gvn>}.
5327:
5328: @item @code{KILL}
5329: Trigger will fire when @emph{<gvn>} is @code{KILL}ed.
5330:
5331: @item @code{NEXT}
5332: Trigger will fire when intrinsic function @code{$NEXT} is called on @emph{<gvn>}.
5333:
5334: @item @code{ORDER}
5335: Trigger will fire when intrinsic function @code{$ORDER} is called on @emph{<gvn>}.
5336:
5337: @item @code{QUERY}
5338: Trigger will fire when intrinsic function @code{$QUERY} is called on @emph{<gvn>}.
5339:
5340: @item @code{SET}
5341: Trigger will fire when @code{SET @emph{<gvn>}=@emph{value}} occurs.
5342:
5343: @item @code{ZDATA}
5344: Trigger will fire when intrinsic function @code{ZDATA} is called on @emph{<gvn>}.
5345:
5346: @end table
5347:
5348: When a @code{TRIGGER} event occurs, the @code{"GLOBAL"} node of the @code{^$EVENT} structured system variable will be populated with the global reference that invoked the trigger event.
5349:
5350: If a @code{SET} or @code{KILL} trigger was the source of the @code{TRIGGER} event, the @code{OLD_VALUE} node of @code{^$EVENT} will be populated with original value of @code{^$EVENT("GLOBAL")} prior to the change, and @code{NEW_VALUE} will be populated with the new value. This allows triggers to contain logic to undo global changes. This functionality can also be used to provide auditing of specific global changes.
5351:
5352: The following example shows a trigger implemented for @code{SET} operations on the @code{^DD} global.
5353:
5354: @example
5355: TRIGGER ;
5356: ;
5357: ; Set up a SET trigger on ^DD
5358: ;
5359: SET ^$JOB($JOB,"EVENT","TRIGGER","SET:^DD")="ONSET^TRIGGER"
5360: ;
5361: ; Enable the TRIGGER event class
5362: ;
5363: ASTART "TRIGGER"
5364: ;
5365: ; Try setting a node in ^DD
5366: ;
5367: SET ^DD(1)="Test"
5368: ;
5369: ; Quit
5370: ;
5371: QUIT
5372: ;
5373: ;
5374: ONSET ;
5375: WRITE "The "_^$EVENT("GLOBAL")_" global node was SET.",!
5376: QUIT
5377: @end example
5378:
5379: 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($JOB,"EVENT","TRIGGER",...)}.
5380:
5381: @node Synchronous Event Handling
5382: @chapter Synchronous Event Handling
5383:
5384: @node GUI Programming with MWAPI
5385: @chapter GUI Programming with MWAPI
5386:
5387: @node User-Defined Z Commands
5388: @chapter User-Defined Z Commands
5389:
5390: @node User-Defined Z Functions
5391: @chapter User-Defined Z Functions
5392:
5393: @cindex z functions, user-defined
5394:
5395: @node User-Defined SSVNs
5396: @chapter User-Defined SSVNs
5397:
5398: @cindex structured system variables, user-defined
5399: @cindex structured system variables
5400:
5401: @node Language Dialects
5402: @chapter Language Dialects
5403:
5404: @cindex language dialects
5405: @cindex dialects, language
5406:
5407:
5408: @node System Library Routines
5409: @chapter System Library Routines
5410: @cindex system library routines
5411:
5412: @section ^%ZCOLUMNS
5413: @cindex ^%ZCOLUMNS
5414: @cindex system library routines, ^%ZCOLUMNS
5415:
5416: This routine is the implementation of the @code{$ZCOLUMNS} intrinsic special variable.
5417:
1.28 snw 5418: @section %SYSINIT
5419: @cindex %SYSINIT
5420: @cindex system library routines, %SYSINIT
1.1 snw 5421:
5422: This routine is the default startup routine for FreeM running in direct mode.
5423:
5424: Running @code{DO INFO} from direct mode will use this routine to display information about the current FreeM status and namespace configuration.
5425:
5426: @section ^%ZHELP
5427: @cindex ^%ZHELP
5428: @cindex system library routines, ^%ZHELP
5429:
5430: 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}.
5431:
5432: @section ^%ZROWS
5433: @cindex ^%ZROWS
5434: @cindex system library routines, ^%ZROWS
5435:
5436: This routine is the implementation of the @code{$ZROWS} intrinsic special variable.
5437:
5438: @node Interrupt Handling
5439: @chapter Interrupt Handling
5440: @cindex interrupt handling
5441:
1.22 snw 5442: When FreeM receives the @code{SIGINT} signal, either by pressing @code{Ctrl-C} during program execution, or by external signal from the operating system, the FreeM environment daemon, or another external process, one of two things can happen, depending on the state of the @code{$ZI} special variable:
1.1 snw 5443:
5444: @table @asis
5445: @item @code{$ZI} evaluates @emph{true}
5446: In this case, the @code{ZINRPT} error is raised, and normal error handling procedures apply. If neither @code{$ZTRAP} nor @code{$ETRAP} are set, FreeM prints an error diagnostic on the home device and will exit the FreeM process in application mode (i.e., the @code{freem} executable was started with the @code{--routine} or @code{-r} flag), or return to the direct mode prompt otherwise.
5447:
5448: This is the default behavior of FreeM.
5449: @item @code{$ZI} evaluates @emph{false}
5450: 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.
5451:
5452: Checking the value of @code{$ZCONTROLC} will reset it to @emph{false}.
5453: @end table
5454:
5455: In either case, if asynchronous event handling is enabled for the @code{INTERRUPT} event class (i.e., @code{ASTART "INTERRUPT"} or @code{ASTART} have been invoked by the current process), an asynchronous event of event class @code{INTERRUPT} and event identifier @code{SIGINT} will be enqueued.
5456:
5457: @node Error Processing
5458: @chapter Error Processing
5459: @cindex error processing
5460:
5461: FreeM exposes three means of processing M program execution errors:
5462:
5463: @table @emph
5464:
5465: @item FreeM-style error processing
5466: FreeM-style error processing exposes a read/write error trap in @code{$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.
5467:
5468: @item DSM 2.0-style error processing
5469: 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.
5470:
5471: @item Standard error processing
5472: 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.
5473:
5474: 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.
5475:
5476: @end table
5477:
5478: For further information on switching between FreeM-style and DSM 2.0-style @code{$ZTRAP} error handling, see the documentation for the @code{BREAK} command.
5479:
5480: @node FreeM Error Codes
5481: @chapter FreeM Error Codes
5482: @cindex Error Codes
5483:
5484: @table @asis
5485:
5486: @item @code{ZINRPT} - @emph{interrupt}
5487: Raised when an interrupt signal is received.
5488:
5489: @item @code{ZBKERR} - @emph{BREAK point}
5490: Raised when a @code{BREAK} point is reached.
5491:
5492: @item @code{ZNOSTAND} - @emph{non standard syntax}
5493: Raised when features incompatible with the current value of @code{$DIALECT} are used.
5494:
5495: @item @code{ZUNDEF} - @emph{variable not found}
5496: 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}.
5497:
5498: @item @code{ZLBLUNDEF} - @emph{label not found}
5499: Raised when a referenced label is not found.
5500:
5501: @item @code{ZMISSOPD} - @emph{missing operand}
5502: Raised when an operand is missing from an expression.
5503:
5504: @item @code{ZMISSOP} - @emph{missing operator}
5505: Raised when an operator is missing from an expression.
5506:
5507: @item @code{ZILLOP} - @emph{unrecognized operator}
5508: Raised when an unrecognized operator is encountered in an expression.
5509:
5510: @item @code{ZQUOTER} - @emph{unmatched quotes}
5511: Raised when unbalanced quotes are encountered.
5512:
5513: @item @code{ZCOMMAER} - @emph{comma expected}
5514: Raised when a comma is expected in program syntax but is not found.
5515:
5516: @item @code{ZASSIGNER} - @emph{equals '=' expected}
5517: Raised when an equals sign is expected in program syntax but is not found.
5518:
5519: @item @code{ZARGER} - @emph{argument not permitted}
5520: Raised when an argument is encountered in a syntactic position where arguments are not permitted.
5521:
5522: @item @code{ZSPACER} - @emph{blank ' ' expected}
5523: Raised when a space character is expected in program syntax but is not found.
5524:
5525: @item @code{ZBRAER} - @emph{unmatched parentheses}
5526: Raised when unbalanced parentheses are detected in program syntax.
5527:
5528: @item @code{ZLVLERR} - @emph{level error}
5529: Raised when a level error occurs.
5530:
5531: @item @code{ZDIVER} - @emph{divide by zero}
5532: Raised when program code attempts to divide by zero. Deprecated in favor of standard error code @code{M9}.
5533:
5534: @item @code{ZILLFUN} - @emph{function not found}
5535: Raised when program code attempts to call intrinsic or extrinsic functions that are not defined.
5536:
5537: @item @code{ZFUNARG} - @emph{wrong number of function arguments}
5538: Raised when an intrinsic or extrinsic function is called with the wrong number of arguments.
5539:
5540: @item @code{ZZTERR} - @emph{ZTRAP error}
5541: Raised when a @code{$ZTRAP} error occurs.
5542:
5543: @item @code{ZNEXTERR} - @emph{$NEXT/$ORDER error}
5544: Raised when an error occurs in @code{$NEXT} or @code{$ORDER}.
5545:
5546: @item @code{ZSELER} - @emph{$SELECT error}
5547: Raised when an error occurs in @code{$SELECT}
5548:
5549: @item @code{ZCMMND} - @emph{illegal command}
5550: Raised when program code attempts to execute an illegal command.
5551:
5552: @item @code{ZARGLIST} - @emph{argument list incorrect}
5553: Raised when the argument list supplied to an M language element does not match that language element's syntactic requirements.
5554:
5555: @item @code{ZINVEXPR} - @emph{invalid expression}
5556: Raised when an invalid expression is encountered.
5557:
5558: @item @code{ZINVREF} - @emph{invalid reference}
5559: Raised when an invalid variable reference is encountered.
5560:
5561: @item @code{ZMXSTR} - @emph{string too long}
5562: Raised when a string is encountered that exceeds @code{^$SYSTEM("STRING_MAX")}.
5563:
5564: @item @code{ZTOOPARA} - @emph{too many parameters}
5565: Raised when too many parameters are passed to a function or subroutine.
5566:
5567: @item @code{ZNOPEN} - @emph{unit not open}
5568: Raised when attempting to access an I/O channel that has not been opened.
5569:
5570: @item @code{ZNODEVICE} - @emph{unit does not exist}
5571: Raised when attempting to access a device that does not exist.
5572:
5573: @item @code{ZPROTECT} - @emph{file protection violation}
5574: Raised when attempting to access a file or device to which you do not have permission.
5575:
5576: @item @code{ZGLOBER} - @emph{global not permitted}
5577: Raised when attempting to use a global in a syntactic element where global variables are not permitted.
5578:
5579: @item @code{ZFILERR} - @emph{file not found}
5580: Raised when attempting to access a file that does not exist.
5581:
5582: @item @code{ZPGMOV} - @emph{program overflow}
5583: Raised when a program overflows the limits of a routine buffer.
5584:
5585: @item @code{ZSTKOV} - @emph{stack overflow}
5586: Raised when @code{DO}, @code{FOR}, or @code{XECUTE} nesting levels exceed the value in @code{^$SYSTEM("NESTLEVLS")}.
5587:
5588: @item @code{ZSTORE} - @emph{symbol table overflow}
5589: Raised when program code attempts to store too much data in the local symbol table. Should not occur unless symbol table auto-adjust is disabled.
5590:
5591: @item @code{ZNOREAD} - @emph{file won't read}
5592: Raised when program code attempts to read from an unreadable file.
5593:
5594: @item @code{ZNOWRITE} - @emph{file won't write}
5595: Raised when program code attempts to write to an unwritable file.
5596:
5597: @item @code{ZNOPGM} - @emph{routine not found}
5598: Raised when an attempt is made to load or execute a routine that does not exist in the current namespace.
5599:
5600: @item @code{ZNAKED} - @emph{illegal naked reference}
5601: Raised when an attempt is made to use an illegal naked reference.
5602:
5603: @item @code{ZSBSCR} - @emph{illegal subscript}
5604: Raised when an illegal subscript access is attempted.
5605:
5606: @item @code{ZISYNTX} - @emph{insert syntax}
5607: Raised when illegal insert syntax is used.
5608:
5609: @item @code{ZDBDGD} - @emph{global data degradation}
5610: Raised when corruption is detected in global data files.
5611:
5612: @item @code{ZKILLER} - @emph{job kill signal}
5613: Raised on a job kill signal.
5614:
5615: @item @code{ZHUPER} - @emph{hangup signal}
5616: Raised on a job hangup signal.
5617:
5618: @item @code{ZMXNUM} - @emph{numeric overflow}
5619: Raised when an assignment or expression result exceeds @code{$ZPRECISION}.
5620:
5621: @item @code{ZNOVAL} - @emph{function returns no value}
5622: Raised when a function does not return a value. Extrinsic functions must @code{QUIT} with a value.
5623:
5624: @item @code{ZTYPEMISMATCH} - @emph{type mismatch}
5625: Raised when a type mismatch occurs.
5626:
5627: @item @code{ZMEMOV} - @emph{out of memory}
5628: Raised when FreeM runs out of heap memory.
5629:
5630: @item @code{ZNAMERES} - @emph{error in name resolution}
5631: Raised when an attempted name resolution fails.
5632:
5633: @item @code{ZSCKCREAT} - @emph{error creating socket}
5634: Raised when an error occurs creating a socket for network I/O.
5635:
5636: @item @code{ZSCKIFAM} - @emph{invalid address family (must be IPV4 or IPV6)}
5637: Raised when the address family specified in an @code{OPEN} command for a socket I/O channel is not IPV4 or IPV6.
5638:
5639: @item @code{ZSCKITYP} - @emph{invalid connection type (must be TCP or UDP)}
5640: Raised when the connection type specified in an @code{OPEN} command for a socket I/O channel is not @code{TCP} or @code{UDP}.
5641:
5642: @item @code{ZSCKIPRT} - @emph{invalid port number}
5643: 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.
5644:
5645: @item @code{ZSCKCERR} - @emph{connection error}
5646: Raised when an error occurs on a @code{USE <channel>:/CONNECT} command.
5647:
5648: @item @code{ZSCKAERR} - @emph{USE action invalid for connection type (possibly CONNECT on UDP socket?)}
5649: Raised when an attempt is made to @code{USE <channel>:/CONNECT} on a UDP socket I/O channel. The UDP protocol is connectionless.
5650:
5651: @item @code{ZSCKACON} - @emph{attempted to CONNECT an already-connected socket}
5652: Raised when an attempt is made to @code{USE <channel>:/CONNECT} on a TCP socket I/O channel that is already connected.
5653:
5654: @item @code{ZSCKNCON} - @emph{attempted to READ from a disconnected TCP socket}
5655: Raised when an attempt is made to @code{READ} a TCP socket that has not yet been connected.
5656:
5657: @item @code{ZSCKEOPT} - @emph{error setting socket options}
5658: Raised when an error is encountered while setting socket options.
5659:
5660: @item @code{ZSCKERCV} - @emph{error in READ from socket}
5661: Raised when an error occurs in a socket I/O channel @code{READ}.
5662:
5663: @item @code{ZSCKESND} - @emph{error in WRITE to socket}
5664: Raised when an error occurs while attempting to @code{WRITE} to a socket I/O channel.
5665:
5666: @item @code{ZNORPI} - @emph{^$ZRPI only supported on Raspberry Pi hardware}
5667: Raised when an attempt is made to use the @code{^$ZRPI} structured system variable on a platform other than the Raspberry Pi single-board computer.
5668:
5669: @item @code{ZCREDEF} - @emph{cannot redefine CONST}
5670: Raised when attempts are made to redefine a @code{CONST} after its initial definition.
5671:
5672: @item @code{ZCMODIFY} - @emph{cannot modify CONST}
5673: Raised when attempts are made to change the value of a @code{CONST}.
5674:
5675: @item @code{ZFILEXWR} - @emph{cannot open existing file for WRITE}
5676: Raised when an attempt is made to open an existing file in write (but not append) mode.
5677:
5678: @item @code{INEWMULT} - @emph{initializing NEW with multiple setarguments not supported}
5679: Raised when you attempt to use multiple setarguments with initializing @code{NEW}, e.g. @code{NEW X=2,Y=3}.
5680:
5681: @item @code{ZECODEINV} - @emph{invalid value for $ECODE}
5682: Raised when attempts are made to set @code{$ECODE} to an invalid error code value. Obsolete and replaced by standard error code @code{M101}.
5683:
5684: @item @code{ZASSERT} - @emph{programmer assertion failed}
5685: Raised when an @code{ASSERT} expression's result is not true.
5686:
5687: @item @code{ZUSERERR} - @emph{user-defined error}
5688: Raised when program code calls @code{THROW} with an error code argument for which the first character is @code{U}, or when @code{$ECODE} is set to an error code for which the first character is @code{U}.
5689:
5690: Custom error messages for @code{ZUSERERR} may be set in @code{^$JOB($JOB,"USER_ERRORS",<user_error_code>)}, where @code{<user_error_code>} represents the custom error code.
5691:
5692: For example:
5693:
5694: @example
1.22 snw 5695: DEFAULT.USER> S ^$JOB($JOB,"USER_ERRORS","UBLACKHOLE")="black hole encountered"
1.1 snw 5696:
5697:
1.22 snw 5698: DEFAULT.USER> THROW UBLACKHOLE
1.1 snw 5699:
5700:
5701: >> Error UBLACKHOLE: black hole encountered in SYSTEM::^%SYSINIT [$STACK = 0]
5702: >> THROW UBLACKHOLE
5703: ^
5704: @end example
5705:
5706: @item @code{ZSYNTERR} - @emph{syntax error}
5707: Raised when a syntax error without a more specific error code is encountered.
5708:
5709: @item @code{ZCTRLB} - @emph{break}
5710: Pseudo-error used by the FreeM debugger. Not visibly raised in normal program operation.
5711:
5712: @item @code{ZASYNC} - @emph{asynchronous interruption}
5713: Pseudo-error used by the FreeM asynchronous events subsystem. Not visibly raised in normal program operation.
5714:
5715: @item @code{M1} - @emph{naked indicator undefined}
5716: Raised when an attempt is made to use a naked reference before the naked indicator is set.
5717:
5718: @item @code{M2} - @emph{invalid combination with $FNUMBER code atom}
5719:
5720:
5721: @item @code{M3} - @emph{$RANDOM seed less than 1}
5722:
5723:
5724: @item @code{M4} - @emph{no true condition in $SELECT}
5725:
5726:
5727: @item @code{M5} - @emph{line reference less than zero}
5728:
5729:
5730: @item @code{M6} - @emph{undefined local variable}
5731:
5732:
5733: @item @code{M7} - @emph{undefined global variable}
5734:
5735:
5736: @item @code{M8} - @emph{undefined intrinsic special variable}
5737:
5738:
5739: @item @code{M9} - @emph{divide by zero}
5740:
5741:
5742: @item @code{M10} - @emph{invalid pattern match range}
5743:
5744:
5745: @item @code{M11} - @emph{no parameters passed}
5746:
5747:
5748: @item @code{M12} - @emph{invalid line reference (negative offset)}
5749:
5750:
5751: @item @code{M13} - @emph{invalid line reference (line not found)}
5752:
5753:
5754: @item @code{M14} - @emph{line level not 1}
5755:
5756:
5757: @item @code{M15} - @emph{undefined index variable}
5758:
5759:
5760: @item @code{M16} - @emph{argumented QUIT not allowed}
5761:
5762:
5763: @item @code{M17} - @emph{argumented QUIT required}
5764:
5765:
5766: @item @code{M18} - @emph{fixed length READ not greater than zero}
5767:
5768:
5769: @item @code{M19} - @emph{cannot copy a tree or subtree onto itself}
5770:
5771:
5772: @item @code{M20} - @emph{line must have a formal parameter list}
5773:
5774:
5775: @item @code{M21} - @emph{algorithm specification invalid}
5776:
5777:
5778: @item @code{M22} - @emph{SET or KILL to ^$GLOBAL when data in global}
5779:
5780:
5781: @item @code{M23} - @emph{SET or KILL to ^$JOB for non-existent job number}
5782:
5783:
5784: @item @code{M24} - @emph{change to collation algorithm while subscripted local variables defined}
5785:
5786:
5787: @item @code{M26} - @emph{non-existent environment}
5788:
5789:
5790: @item @code{M27} - @emph{attempt to rollback a transaction that is not restartable}
5791:
5792:
5793: @item @code{M28} - @emph{mathematical function, parameter out of range}
5794:
5795:
5796: @item @code{M29} - @emph{SET or KILL on structured system variable not allowed by implementation}
5797:
5798:
5799: @item @code{M30} - @emph{reference to global variable with different collating sequence within a collating algorithm}
5800:
5801:
5802: @item @code{M31} - @emph{control mnemonic used for device without a mnemonic space selected}
5803:
5804:
5805: @item @code{M32} - @emph{control mnemonic used in user-defined mnemonic space which has no associated line}
5806:
5807:
5808: @item @code{M33} - @emph{SET or KILL to ^$ROUTINE when routine exists}
5809:
5810:
5811: @item @code{M35} - @emph{device does not support mnemonic space}
5812:
5813:
5814: @item @code{M36} - @emph{incompatible mnemonic spaces}
5815:
5816:
5817: @item @code{M37} - @emph{READ from device identified by empty string}
5818:
5819:
5820: @item @code{M38} - @emph{invalid structured system variable subscript}
5821:
5822:
5823: @item @code{M39} - @emph{invalid $NAME argument}
5824:
5825:
5826: @item @code{M40} - @emph{call-by-reference in JOB actual parameter}
5827:
5828:
5829: @item @code{M41} - @emph{invalid LOCK argument within a transaction}
5830:
5831:
5832: @item @code{M42} - @emph{invalid QUIT within a transaction}
5833:
5834:
5835: @item @code{M43} - @emph{invalid range value ($X, $Y}
5836:
5837:
5838: @item @code{M44} - @emph{invalid command outside of a transaction}
5839:
5840:
5841: @item @code{M45} - @emph{invalid GOTO reference}
5842:
5843:
5844: @item @code{M56} - @emph{identifier exceeds maximum length}
5845:
5846:
5847: @item @code{M57} - @emph{more than one defining occurrence of label in routine}
5848:
5849:
5850: @item @code{M58} - @emph{too few formal parameters}
5851:
5852:
5853: @item @code{M60} - @emph{illegal attempt to use an undefined SSVN}
5854:
5855:
5856: @item @code{M101} - @emph{invalid value for $ECODE}
5857:
5858:
5859: @item @code{M102} - @emph{synchronous and asynchronous event processing cannot be simultaneously enabled for the same event class}
5860:
5861:
5862: @item @code{M103} - @emph{invalid event identifier}
5863:
5864:
5865: @item @code{M104} - @emph{ETRIGGER event identifier for IPC event class does not match job process identifier}
5866:
5867:
5868: @end table
5869:
1.35 snw 5870:
1.1 snw 5871: @node System Configuration
5872: @chapter System Configuration
5873: @cindex configuration, system
5874:
5875: @section Installing FreeM
5876: @cindex installation
5877:
1.35 snw 5878: @subsection Installation Methods
1.1 snw 5879:
1.35 snw 5880: FreeM allows the following installation methods:
1.1 snw 5881: @table @asis
1.35 snw 5882: @item Binary Repository
5883: 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 5884:
1.35 snw 5885: If available, this is the simplest method of installing FreeM.
5886: @item Binary Packages
5887: 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.
5888:
5889: See @emph{https://freem.coherent-logic.com/binaries.cfm} for downloads and instructions.
5890: @item Source Archive
5891: 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:
5892:
5893: @example
5894: $ gunzip freem-@emph{<version>}.tar.gz
5895: $ tar xf freem-@emph{<version>}.tar
5896: $ cd freem
5897: $ ./configure # see the Build Configuration section for optional flags
5898: $ make
5899: $ sudo make install
5900: @end example
1.1 snw 5901:
1.35 snw 5902: Once this process has been completed, you may proceed to @emph{Initial Configuration}.
1.1 snw 5903:
1.35 snw 5904: Installation from source archive is the most challenging but flexible supported option for advanced users.
5905: @item CVS Repository
5906: If you wish to try the bleeding-edge development version of FreeM, you may do so by following these steps:
1.1 snw 5907:
1.35 snw 5908: @verbatim
5909: $ cvs -d :pserver:anonymous@cvs.coherent-logic.com:/home/cvsroot co freem
5910: $ cd freem
5911: $ ./autogen.sh
5912: $ ./configure # see the Build Configuration section for optional flags
1.1 snw 5913: $ make
5914: $ sudo make install
1.35 snw 5915: @end verbatim
5916:
5917: Once this process has been completed, you may proceed to @emph{Initial Configuration}.
5918:
5919: 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.
5920:
5921: See the @emph{Contributor Guide} on the @emph{FreeM Wiki} for more information.
5922: @end table
5923: @subsection Build Configuration
5924: @cindex build configuration
5925:
5926: 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:
5927:
5928: @table @asis
1.1 snw 5929:
1.35 snw 5930: @item @code{--enable-mwapi} (EXPERIMENTAL)
5931: 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 5932:
5933: Please consult your operating system's documentation for the correct commands to install the required libraries.
5934:
5935: @emph{Example}
5936:
5937: @example
1.35 snw 5938: $ ./configure --enable-mwapi
1.1 snw 5939: $ make
5940: $ sudo make install
5941: @end example
5942:
1.35 snw 5943: @end table
1.1 snw 5944:
1.35 snw 5945: @subsection Initial Configuration
5946: Once FreeM is installed, you will need to configure it:
1.1 snw 5947:
1.35 snw 5948: @enumerate
5949: @item Create a user and group, each named @emph{freem}, under which FreeM will run
5950: @item Add any user accounts that will need to run FreeM to the @emph{freem} group
5951: @item Have all users added in step 2 sign out and sign in for the new group membership to take effect
5952: @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
5953: @item Run @code{fmadm start environment} with superuser privileges to start the @code{DEFAULT} environment
5954: @item Make sure the environment is ready by running @code{fmadm status environment} with superuser privileges
5955: @end enumerate
5956:
5957: @subsubsection Creating Additional Environments
5958: To create additional environments, do the following steps:
5959:
5960: @enumerate
5961: @item Create a new user and group for the environment @emph{(optional)}
5962: @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)}
5963: @item Run @code{fmadm start environment -e=@emph{<environment>}} to start the environment
5964: @item Run @code{fmadm status environment} to make sure the environment is healthy
5965: @end enumerate
1.1 snw 5966:
1.35 snw 5967: @subsubsection Additional Customization
1.1 snw 5968:
1.35 snw 5969: See the FreeM @emph{environment catalog} at @code{@emph{$PREFIX}/etc/freem/env.conf}, and the @emph{fmadm}(1) @code{man} page for more information.
1.1 snw 5970:
1.35 snw 5971: @emph{$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 5972:
5973: @node Accessing FreeM from C Programs
5974: @chapter Accessing FreeM from C Programs
5975:
5976: 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.
5977:
5978: 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.
5979:
5980: 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.
5981:
5982: 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}.
5983:
5984: @section freem_ref_t Data Structure
5985: @cindex libfreem, data structures: freem_ref_t
5986:
5987: 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.
5988:
5989: The data structure, defined in @file{freem.h}, looks like this:
5990:
5991: @verbatim
5992: typedef struct freem_ref_t {
5993:
5994: /*
5995: * The 'reftype' field can be one of:
5996: *
5997: * MREF_RT_LOCAL
5998: * MREF_RT_GLOBAL
5999: * MREF_RT_SSV
6000: */
6001: short reftype;
6002:
6003: /*
6004: * The 'name' field is the name of the local variable,
6005: * global variable, or SSVN (without ^ or ^$).
6006: */
6007: char name[256];
6008:
6009: /*
6010: * Returned data goes in a string, so you've got to figure out the
6011: * whole M canonical number thing yourself. Good luck. :-)
6012: */
6013: char value[STRLEN];
6014:
6015: short status;
6016:
6017: unsigned int subscript_count;
6018: char subscripts[255][256];
6019:
6020: } freem_ref_t;
6021: @end verbatim
6022:
6023: @emph{freem_ref_t Members}
6024:
6025: @table @asis
6026: @cindex libfreem, freem_ref_t.reftype
6027: @item @option{reftype}
6028: The @option{reftype} member determines whether we are operating on a local variable, a global variable, or a structured system variable. It may be set to any of following constants: @code{MREF_RT_LOCAL}, @code{MREF_RT_GLOBAL}, or @code{MREF_RT_SSV}.
6029:
6030: @cindex libfreem, freem_ref_t.name
6031: @item @option{name}
6032: The @option{name} member contains the name of the global, local, or SSVN to be accessed. You @emph{must not} include leading characters, such as @code{^} or @code{^$}.
6033:
6034: @cindex libfreem, freem_ref_t.value
6035: @item @option{value}
6036: This member contains the value read from or the value to be written to the global, local, or SSVN.
6037:
6038: @cindex libfreem, freem_ref_t.status
6039: @item @option{status}
6040: This member gives us various API status values after the API call returns. In general, this value is also returned by each API function.
6041:
6042: @cindex libfreem, freem_ref_t.subscript_count
6043: @item @option{subscript_count}
6044: 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.
6045:
6046: @cindex libfreem, freem_ref_t.subscripts
6047: @item @option{subscripts}
6048: A two-dimensional array containing the subscripts to which we are referring in this API call.
6049:
6050: @end table
6051:
6052: @section freem_ent_t Data Structure
6053: @cindex libfreem, data structures: freem_ent_t
6054:
6055: 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()}).
6056:
6057: The data structure, defined in @file{freem.h}, looks like this:
6058:
6059: @verbatim
6060: typedef struct freem_ent_t {
6061:
6062: /* name of function or procedure entry point */
6063: char name[256];
6064:
6065: /* return value */
6066: char value[STRLEN];
6067:
6068: /* value of ierr on return */
6069: short status;
6070:
6071: /* argument count and array */
6072: unsigned int argument_count;
6073: char arguments[255][256];
6074:
6075: } freem_ent_t;
6076: @end verbatim
6077:
6078: @emph{freem_ent_t Members}
6079:
6080: @table @asis
6081:
6082: @item @option{name}
6083: @cindex libfreem, freem_ent_t.name
6084: The @option{name} member contains the name of the extrinsic function or procedure to be called.
6085:
6086: @cindex libfreem, freem_ent_t.value
6087: @item @option{value}
6088: This member contains the value returned by the function called. Not used by @code{freem_procedure()}.
6089:
6090: @cindex libfreem, freem_ent_t.status
6091: @item @option{status}
6092: 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}.
6093:
6094: @cindex libfreem, freem_ent_t.argument_count
6095: @item @option{argument_count}
6096: 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.
6097:
6098: @cindex libfreem, freem_ent_t.arguments
6099: @item @option{arguments}
6100: A two-dimensional array containing the arguments to be passed into the extrinsic function or procedure being called.
6101:
6102: @end table
6103:
6104: @section freem_init()
6105: @cindex libfreem, freem_init()
6106:
6107: Initializes @code{libfreem} in preparation for calling other APIs.
6108:
6109: @emph{Synopsis}
6110:
6111: @code{pid_t freem_init(char *environment_name, char *namespace_name);}
6112:
6113: @emph{Parameters}
6114:
6115: @table @asis
6116: @item @code{environment_name}
6117: Specifies the environment to use.
6118: @item @code{namespace_name}
6119: Specifies the namespace to use.
6120: @end table
6121:
6122: @emph{Return Values}
6123:
6124: Returns the process ID of the @code{libfreem} process on success, or @code{-1} on failure.
6125:
6126: @emph{Example}
6127:
6128: This example prompts the user to enter a FreeM namespace and then attempts to initialize @code{libfreem} to use the selected namespace.
6129:
6130: @verbatim
6131: #include <stdio.h>
6132: #include <string.h>
6133: #include <freem.h>
6134:
6135: int main(int argc, char **argv, char **envp)
6136: {
6137: char namespace[256];
6138:
6139: /* get the namespace name to use */
6140: printf("Enter FreeM namespace to use: ");
6141: fgets(namespace, 255, stdin);
6142:
6143: /* remove the trailing newline */
6144: namespace[strcspn(buffer, "\n")] = '\0';
6145:
6146: /* initialize libfreem using the provided namespace */
6147: if(freem_init("DEFAULT", namespace) == TRUE) {
6148: printf("\nSuccess\n");
6149: }
6150: else {
6151: printf("\nFailure\n");
6152: }
6153:
6154: return 0;
6155: }
6156: @end verbatim
6157:
6158: @section freem_version()
6159: @cindex libfreem, freem_version()
6160:
6161: Returns the version of FreeM in use.
6162:
6163: @emph{Synopsis}
6164:
6165: @code{short freem_version(char *result);}
6166:
6167: @emph{Parameters}
6168:
6169: @table @asis
6170: @item @code{result}
6171: 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.
6172: @end table
6173:
6174: @emph{Return Value}
6175:
6176: Returns @code{0}.
6177:
6178: @emph{Example}
6179:
6180: This example will display the FreeM version on standard output.
6181:
6182: @verbatim
6183: #include <stdio.h>
6184: #include <string.h>
6185: #include <freem.h>
6186:
6187: int main(int argc, char **argv, char **envp)
6188: {
6189: char version[20] = {0};
6190:
6191: freem_init(``USER'');
6192: freem_version(version);
6193:
6194: printf(``FreeM version: %s\n'', version);
6195:
6196: }
6197: @end verbatim
6198:
6199: @section freem_set()
6200: @cindex libfreem, freem_set()
6201:
6202: Sets a FreeM local node, global node, or writable SSVN node.
6203:
6204: @emph{Synopsis}
6205:
6206: @code{short freem_set(freem_ref_t *ref);}
6207:
6208: @emph{Parameters}
6209:
6210: @table @asis
6211: @item @code{freem_ref_t}
6212: This parameter is a pointer to a @code{freem_ref_t} struct. The caller must allocate the memory for this struct.
6213: @end table
6214:
6215: @emph{Return Value}
6216:
6217: Returns @code{OK} on success, or one of the other error values defined in @code{merr.h}.
6218:
6219: @emph{Example}
6220:
6221: This example sets the value @code{blue} into global node @code{^car("color")}.
6222:
6223: @verbatim
6224: #include <stdio.h>
6225: #include <string.h>
6226: #include <freem.h>
6227:
6228: int main(int argc, char **argv, char **envp)
6229: {
6230: freem_ref_t ref;
6231:
6232: /* we're setting a global */
6233: ref.reftype = MREF_RT_GLOBAL;
6234:
6235: /* access global "car" */
6236: strcpy(ref.name, "car");
6237:
6238: /* set up the subscripts */
6239: ref.subscript_count = 1;
6240: strcpy(ref.subscripts[0], "color");
6241:
6242:
6243: /* use the USER namespace */
6244: freem_init("USER");
6245:
6246: /* write the data out */
6247: freem_set(&ref);
6248:
6249: }
6250: @end verbatim
6251:
6252: @section freem_get()
6253: @cindex libfreem, freem_get()
6254:
6255: Retrieves a FreeM local node, global node, or writable SSVN node.
6256:
6257: @emph{Synopsis}
6258:
6259: @code{short freem_get(freem_ref_t *ref);}
6260:
6261: @emph{Parameters}
6262:
6263: @table @asis
6264: @item @code{freem_ref_t}
6265: This parameter is a pointer to a @code{freem_ref_t} struct. The caller must allocate the memory for this struct.
6266: @end table
6267:
6268: @emph{Return Value}
6269:
6270: Returns @code{OK} on success, or one of the other error values defined in @code{merr.h}.
6271:
6272: @emph{Example}
6273:
6274: This example retrieves the character set of the current process.
6275:
6276: @verbatim
6277: #include <stdio.h>
6278: #include <sys/types.h>
6279: #include <unistd.h>
6280: #include <string.h>
6281: #include <freem.h>
6282:
6283: int main(int argc, char **argv, char)
6284: {
6285: pid_t pid;
6286: freem_ref_t ref;
6287:
6288: /* get the PID of this process */
6289: pid = getpid();
6290:
6291: /* we want to access an SSVN */
6292: ref.reftype = MREF_RT_SSV;
6293:
6294: /* set up the name and subscripts */
6295: strcpy(ref.name, "JOB");
6296:
6297: ref.subscript_count = 2;
6298: sprintf(ref.subscripts[0], "%d", pid);
6299: strcpy(ref.subscripts[1], "CHARACTER");
6300:
6301: /* initialize libfreem, using the USER namespace */
6302: freem_init("USER");
6303:
6304: /* call libfreem API */
6305: freem_get(&ref);
6306:
6307: /* output the character set info */
6308: printf("PID %d character set is '%s'\n", pid, ref.value);
6309: }
6310: @end verbatim
6311:
6312: @section freem_kill()
6313: @cindex libfreem, freem_kill()
6314:
6315: Deletes a FreeM local node, global node, or killable SSVN node, as well as all of its children.
6316:
6317: @emph{short freem_kill(freem_ref_t *ref);}
6318:
6319: @emph{Parameters}
6320:
6321: @table @asis
6322: @item @code{freem_ref_t}
6323: This parameter is a pointer to a @code{freem_ref_t} struct. The caller must allocate the memory for this struct.
6324: @end table
6325:
6326: @emph{Return Value}
6327:
6328: Returns @code{OK} on success, or one of the other error values defined in @code{merr.h}.
6329:
6330: @emph{Example}
6331:
6332: @verbatim
6333: #include <stdio.h>
6334: #include <string.h>
6335: #include <freem.h>
6336:
6337: int main(int argc, char **argv, char **envp)
6338: {
6339: freem_ref_t ref;
6340:
6341: /* we're killing a global node */
6342: ref.reftype = MREF_RT_GLOBAL;
6343:
6344: /* access global "car" */
6345: strcpy(ref.name, "car");
6346:
6347: /* set up the subscripts */
6348: ref.subscript_count = 0;
6349:
6350: /* use the USER namespace */
6351: freem_init("USER");
6352:
6353: /* kill the global and all its descendant subscripts */
6354: freem_kill(&ref);
6355: }
6356: @end verbatim
6357:
6358: @section freem_data()
6359: @cindex libfreem, freem_data()
6360:
6361: @section freem_order()
6362: @cindex libfreem, freem_order()
6363:
6364: @section freem_query()
6365: @cindex libfreem, freem_query()
6366:
6367: @section freem_lock()
6368: @cindex libfreem, freem_lock()
6369:
6370: @section freem_unlock()
6371: @cindex libfreem, freem_unlock()
6372:
6373: @section freem_tstart()
6374: @cindex libfreem, freem_tstart()
6375:
6376: @section freem_trestart()
6377: @cindex libfreem, freem_trestart()
6378:
6379: @section freem_trollback()
6380: @cindex libfreem, freem_trollback()
6381:
6382: @section freem_tlevel()
6383: @cindex libfreem, freem_tlevel()
6384:
6385: @section freem_tcommit()
6386: @cindex libfreem, freem_tcommit()
6387:
6388: @section freem_function()
6389: @cindex libfreem, freem_function()
6390:
6391: @section freem_procedure()
6392: @cindex libfreem, freem_procedure()
6393:
6394: @node FreeM Administrator
6395: @appendix FreeM Administrator
6396: @cindex utilities, system management
6397: @cindex utilities, fmadm
6398: @cindex fmadm
6399:
6400: The @code{fmadm} utility is the preferred method of managing a FreeM installation, and will eventually replace all of the existing utilities.
6401: Unlike the existing, legacy utilities, @code{fmadm} presents a consistent, simple interface for all FreeM management tasks, and is namespace-aware.
6402: This appendix will document each @code{fmadm} facility as it is implemented, until all of the legacy utilities have been replaced.
6403:
6404: The @code{fmadm} utility's functions all follow the below, consistent syntax:
6405:
6406: @example
6407: usage: fmadm <action> <object> <namespace> [OPTIONS]
6408: @end example
6409:
6410: The @emph{action} keyword can be one of the following:
6411:
6412: @table @emph
6413:
6414: @item list
6415: Lists instances of @emph{object}
6416:
6417: @item examine
6418: Examines a single instance of @emph{object}
6419:
6420: @item verify
6421: Verifies the integrity of @emph{object}
6422:
6423: @item compact
6424: Compacts @emph{object}
6425:
6426: @item repair
6427: Repairs integrity problems in @emph{object}
6428:
6429: @item create
6430: Creates an instance of @emph{object}
6431:
6432: @item remove
6433: Removes an instance of @emph{object}
6434:
6435: @item import
6436: Imports an @emph{object}
6437:
6438: @item export
6439: Exports an @emph{object}
6440:
6441: @item backup
6442: Creates a backup of @emph{object}
6443:
6444: @item restore
6445: Restores a backup of @emph{object}
6446:
6447: @item migrate
6448: Migrates an instance of @emph{object} from an older FreeM version to the current version
6449:
6450: @item edit
6451: Edits an instance of @emph{object}
6452:
6453: @end table
6454:
6455: The @emph{object} keyword can be one of the following:
6456:
6457: @table @emph
6458:
6459: @item lock
6460: The FreeM @code{LOCK} table.
6461:
6462: Supported actions are @code{list} and @code{remove}.
6463:
6464: @item journal
6465: FreeM after-image journaling.
6466:
6467: Supported actions are @code{examine} and @code{restore}.
6468:
6469: The @code{examine} action will dump the after-image journal entries for the selected namespace in human-readable format.
6470:
6471: The @code{restore} action will play after-image journals forward for the selected namespace.
6472:
6473: @item namespace
6474: FreeM namespaces (collections of M routines and globals).
6475:
6476: No actions yet implemented.
6477:
6478: @item global
6479: The data files representing each FreeM @emph{global}.
6480:
6481: Supported actions are @code{list}, @code{examine}, @code{remove}, and @code{verify}.
6482:
6483: @item routine
6484: An M routine, stored as a @code{.m} file.
6485:
6486: Supported actions are @code{list}, @code{examine}, @code{remove}, @code{import}, @code{export}, @code{backup}, and @code{edit}.
6487:
6488: @item job
6489: A UNIX process representing an instance of the FreeM runtime.
6490:
6491: Supported actions are @code{list} and @code{examine}.
6492:
6493: @end table
6494:
6495:
6496: @node FreeM Legacy Utilities
6497: @appendix FreeM Legacy Utilities
6498: @cindex utilities, legacy
6499:
6500: @section Global Compactor (gcompact)
6501: @cindex utilities, legacy, gcompact
6502:
6503: Compacts the specified global in place.
6504:
6505: @emph{Syntax}
6506:
6507: @example
6508: gcompact @emph{/path/to/global/file}
6509: @end example
6510:
6511: @section Block Examiner (gfix)
6512: @cindex utilities, gfix
6513:
6514: The @emph{gfix} interactive utility program permits navigation of the B-tree structure of the specified global a block at a time.
6515:
6516: @emph{Syntax}
6517:
6518: @example
6519: gfix @emph{</path/to/global/file>}
6520: @end example
6521:
6522: @section Global Repair Tool (grestore)
6523: @cindex utilities, legacy, grestore
6524:
6525: This utility will fix problems with the specified global.
6526:
6527: @emph{Syntax}
6528:
6529: @example
6530: grestore @emph{</path/to/global/file>}
6531: @end example
6532:
6533: @node FreeM VIEW Commands and Functions
6534: @appendix FreeM VIEW Commands and Functions
6535:
6536: @section VIEW 16: Total Count of Error Messages/View Single Error Message
6537: @cindex VIEW commands/functions, 16, total count of error messages/view single error message
6538:
6539: Unknown semantics
6540:
6541: @section VIEW 17: Intrinsic Z-Commands
6542: @cindex VIEW commands/functions, 17, intrinsic Z-commands
6543:
6544: 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.
6545:
6546: @section VIEW 18: Intrinsic Z-Functions
6547: @cindex VIEW commands/functions, 18, intrinsic Z-functions
6548:
6549: 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.
6550:
6551: @section VIEW 19: Intrinsic Special Variables
6552: @cindex VIEW commands/functions, 19, intrinsic special variables
6553:
6554: Allows the user to retrieve or specify which special variables are implemented internally.
6555:
6556: @section VIEW 20: Break Service Code
6557: @cindex VIEW commands/functions, 20, break service code
6558:
6559: Allows the user to view or specify the code that will be run when a @code{BREAK} is encountered.
6560:
6561: @section VIEW 21: View Size of Last Global
6562: @cindex VIEW commands/functions, 21, view size of last global
6563:
6564: Allows the user to view the size of the last referenced global.
6565:
6566: @section VIEW 22: Count VIEW 22 Aliases
6567: @cindex VIEW commands/functions, 22, count VIEW 22 aliases
6568:
6569: Retrieves the number of VIEW 22 aliases in effect.
6570:
6571: @section VIEW 23: View Contents of Input Buffer
6572: @cindex VIEW commands/functions, 23, input buffer contents
6573:
6574: Retrieves the contents of the I/O input buffer.
6575:
6576: @section VIEW 24: Maximum Number of Screen Rows
6577: @cindex VIEW commands/functions, 24, maximum number of screen rows
6578:
6579: Retrieves the maximum number of screen rows supported in the current FreeM build.
6580:
6581: @section VIEW 25: Maximum Number of Screen Columns
6582: @cindex VIEW commands/functions, 25, maximum number of screen columns
6583:
6584: Retrieves the maximum number of screen columns supported in the current FreeM build.
6585:
6586: @section VIEW 26: DO/FOR/XECUTE Stack Pointer
6587: @cindex VIEW commands/functions, 26, DO/FOR/XECUTE stack pointer
6588:
6589: Retrieves the @code{DO}, @code{FOR}, and @code{XECUTE} stack pointer.
6590:
6591: @section VIEW 27: DO/FOR/XECUTE Stack Pointer (On Error)
6592: @cindex VIEW commands/functions, 27, DO/FOR/XECUTE stack pointer, on error
6593:
6594: Retrieves the @code{DO}, @code{FOR}, and @code{XECUTE} stack pointer (on error).
6595:
6596: @section VIEW 29: Copy Symbol Table
6597: @cindex VIEW commands/functions, 29, copy symbol table
6598:
6599: Copies the symbol table? We aren't currently aware of what this means.
6600:
6601: @section VIEW 30: Inspect Arguments
6602: @cindex VIEW commands/functions, 30, inspect arguments
6603:
6604: Retrieves the arguments passed to the @code{freem} executable.
6605:
6606: @section VIEW 31: Count Environment Variables
6607: @cindex VIEW commands/functions, 31, count environment variables
6608:
6609: Allows the user to inspect the number of variables in the process environment table.
6610:
6611: @emph{Syntax}
6612:
6613: @example
6614: WRITE $VIEW(31),!
6615: @end example
6616:
6617: @node Implementation Limits
6618: @appendix Implementation Limits
6619:
6620: @cindex limitations, memory
6621: @cindex maximum size, routine
6622: @cindex maximum size, global
6623: @cindex maximum size, string
6624:
6625: @node US-ASCII Character Set
6626: @appendix US-ASCII Character Set
6627:
6628: @multitable {Code} {Character}
6629: @item Code @tab Character
6630: @item 000 @tab @code{<NUL>}
6631: @item 001 @tab @code{<SOH>}
6632: @item 002 @tab @code{<STX>}
6633: @item 003 @tab @code{<ETX>}
6634: @item 004 @tab @code{<EOT>}
6635: @item 005 @tab @code{<ENQ>}
6636: @item 006 @tab @code{<ACK>}
6637: @item 007 @tab @code{<BEL>}
6638: @item 008 @tab @code{<BS>}
6639: @item 009 @tab @code{<HT>}
6640: @item 010 @tab @code{<LF>}
6641: @item 011 @tab @code{<VT>}
6642: @item 012 @tab @code{<FF>}
6643: @item 013 @tab @code{<CR>}
6644: @item 014 @tab @code{<SO>}
6645: @item 015 @tab @code{<SI>}
6646: @item 016 @tab @code{<DLE>}
6647: @item 017 @tab @code{<DC1>}
6648: @item 018 @tab @code{<DC2>}
6649: @item 019 @tab @code{<DC3>}
6650: @item 020 @tab @code{<DC4>}
6651: @item 021 @tab @code{<NAK>}
6652: @item 022 @tab @code{<SYN>}
6653: @item 023 @tab @code{<ETB>}
6654: @item 024 @tab @code{<CAN>}
6655: @item 025 @tab @code{<EM>}
6656: @item 026 @tab @code{<SUB>}
6657: @item 027 @tab @code{<ESC>}
6658: @item 028 @tab @code{<FS>}
6659: @item 029 @tab @code{<GS>}
6660: @item 030 @tab @code{<RS>}
6661: @item 031 @tab @code{<US>}
6662: @item 032 @tab @code{<space>}
6663: @item 033 @tab !
6664: @item 034 @tab ``
6665: @item 035 @tab #
6666:
6667:
6668: @end multitable
6669:
6670: @node FreeM Project Coding Standards
6671: @appendix FreeM Project Coding Standards
6672:
6673: @section Module Headers
6674: @cindex coding standards, module headers
6675:
1.4 snw 6676: Module headers should adhere to the following format (where @code{Dollar} should be replaced with a dollar sign):
1.1 snw 6677:
6678: @verbatim
6679: /*
1.4 snw 6680: * DollarIdDollar
1.1 snw 6681: * Function prototypes, structs, and macros for FreeM
6682: * binding library
6683: *
6684: *
1.28 snw 6685: * Author: Serena Willis <snw@coherent-logic.com>
1.1 snw 6686: * Copyright (C) 1998 MUG Deutschland
1.4 snw 6687: * Copyright (C) <Year> Coherent Logic Development LLC
6688: *
6689: * This file is part of FreeM.
6690: *
6691: * FreeM is free software: you can redistribute it and/or modify
6692: * it under the terms of the GNU Affero Public License as published by
6693: * the Free Software Foundation, either version 3 of the License, or
6694: * (at your option) any later version.
6695: *
6696: * FreeM is distributed in the hope that it will be useful,
6697: * but WITHOUT ANY WARRANTY; without even the implied warranty of
6698: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
6699: * GNU Affero Public License for more details.
6700: *
6701: * You should have received a copy of the GNU Affero Public License
6702: * along with FreeM. If not, see <https://www.gnu.org/licenses/>.
6703: *
6704: * DollarLogDollar
1.1 snw 6705: *
1.4 snw 6706: * SPDX-FileCopyrightText: (C) 2025 Coherent Logic Development LLC
6707: * SPDX-License-Identifier: AGPL-3.0-or-later
1.1 snw 6708: **/
6709: @end verbatim
6710:
6711: @section Variable Naming
6712: @cindex coding standards, variable naming
6713:
6714: 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.
6715:
6716: Constants defined via the C preprocessor should be in all uppercase letters, with words within them likewise delimited by underscores, such as:
6717:
6718: @verbatim
6719: #define MY_USEFUL_CONSTANT 1
6720: @end verbatim
6721:
6722: @section Indentation and General Layout
6723: @cindex coding standards, indentation
6724: @cindex coding standards, layout
6725:
6726: 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.
6727:
6728: This project follows a modified version of what is known as the Stroustrup indentation style.
6729:
6730: @section Brace Placement (Functions)
6731: @cindex coding standards, brace placement, functions
6732:
6733: 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.
6734:
6735: Below is a correct example:
6736:
6737: @verbatim
6738: int main(int argc, char **argv, char **envp)
6739: {
6740:
6741: }
6742: @end verbatim
6743:
6744: @section Brace Placement (if-for-while-do)
6745: @cindex coding standards, brace placement, if-for-while-do
6746:
6747: 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}:
6748:
6749: @verbatim
6750: if (x) {
6751: ...
6752: }
6753: else {
6754: ...
6755: }
6756:
6757: while (1) {
6758: ...
6759: }
6760:
6761: for (i = 1; i < 10; i++) {
6762: ...
6763: }
6764:
6765: do {
6766: ...
6767: } while (x);
6768: @end verbatim
6769:
6770: Single-statement if blocks should be isolated to a single line:
6771:
6772: @verbatim
6773: if (x) stmt();
6774: @end verbatim
6775:
6776: not:
6777:
6778: @verbatim
6779: if (x)
6780: stmt ();
6781: @end verbatim
6782:
6783: 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.
6784:
6785: 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:
6786:
6787: @verbatim
6788: if (x) {
6789: foo();
6790: }
6791: else if (y) {
6792: bar();
6793: }
6794: else {
6795: bas();
6796: }
6797: @end verbatim
6798:
6799: @section Labels and goto
6800: @cindex coding standards, labels
6801: @cindex coding standards, goto
6802:
6803: Labels must begin in column 1, and have two lines of vertical space above and one beneath.
6804:
6805: @section Preprocessor Conditionals
6806: @section coding standards, preprocessor conditionals
6807:
6808: I have struggled with this, but have settled upon the standard practice of keeping them in column 1.
6809:
6810: @section Overall Program Spacing
6811: @cindex coding standards, spacing of programs
6812:
6813: @itemize @bullet
6814: @item
6815: Variable declarations fall immediately beneath the opening curly brace, and should initialize the variable right there whenever initialization is used.
6816:
6817: @item
6818: One line between the last variable declaration and the first line of real code.
6819:
6820: @item
6821: 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.
6822:
6823: @item
6824: 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.
6825: @end itemize
6826:
6827: @section The switch() Statement
6828: @cindex coding standards, switch()
6829:
6830: 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:
6831:
6832: @verbatim
6833: switch(foo) {
6834:
6835: case some_const:
6836: foo();
6837:
6838: break;
6839:
6840: case some_other_const:
6841: bar();
6842:
6843: break;
6844:
6845: default:
6846: exit(1);
6847:
6848: break;
6849: }
6850: @end verbatim
6851:
6852: @section Comments
6853: @cindex coding standards, comments
6854:
6855: We use C-style comments (@code{/* comment */}) exclusively, even on single-line comments. C++ comments (@code{// comment}) are not permitted.
6856:
6857: @node Index
6858: @unnumbered Index
6859:
6860: @printindex cp
6861:
6862: @bye
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