Annotation of freem/doc/freem.texi, revision 1.37
1.1 snw 1: \input texinfo
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:
10:
1.5 snw 11: Copyright @copyright{} 2014-2025 Coherent Logic Development LLC
1.1 snw 12:
13: @quotation
14: Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover texts, and with no Back-Cover Texts.
15: @end quotation
16: @end copying
17:
18: @titlepage
19:
20: @title The FreeM Manual
21: @subtitle @sc{The Official Manual of FreeM}
1.32 snw 22: @subtitle Version 0.64.0-rc1
1.1 snw 23: @c@vskip 10pt
24: @c@center @image{freem-logo-sm,,,,.png}
25: @author Serena Willis
26: @page
27: @vskip 0pt plus 1filll
28: @insertcopying
29: @end titlepage
30: @contents
31:
32: @ifnottex
33: @node Top
34: @top The FreeM Manual
35:
36: This is the official manual for the FreeM programming language.
37: @end ifnottex
38:
39: @dircategory The FreeM Manual
40: @direntry
41: * FreeM: (freem). The FreeM M programming language.
42: @end direntry
43:
44: @menu
45: * Introduction:: About the FreeM Project, its history, and its goals.
1.36 snw 46: * Document Conventions:: Conventions used in this manual.
1.1 snw 47: * FreeM Invocation:: How to invoke FreeM from the command line.
1.22 snw 48: * The FreeM Environment Daemon:: Managing shared resources in the FreeM environment.
1.1 snw 49: * The FreeM Direct-Mode Environment:: Executing M programs interactively.
1.36 snw 50: * Debugging:: The program development cycle of FreeM.
1.1 snw 51:
52: * Directives:: Per-Routine Language Directives.
53: * Intrinsic Special Variables:: Intrinsic Special Variables.
54: * Intrinsic Functions:: Intrinsic Functions.
55: * OBJECT Methods:: Methods for OBJECT variables.
56: * STRING Methods:: Methods for STRING variables.
57: * Commands:: Commands.
58: * Structured System Variables:: Structured System Variables.
59: * Operators:: FreeM Operators.
60:
61: * Routines:: The units of M code in FreeM.
62: * Types:: FreeM data types.
63: * Globals:: FreeM persistent sparse arrays.
64: * Concurrency Control:: @code{LOCK}ing and transaction processing.
65: * Local Variables:: In-memory variables.
66: * Scoping:: Scoping in FreeM.
67: * Decision Constructs:: @code{IF}, @code{THEN}, @code{ELSE}, @code{$SELECT}, and postconditionals.
68: * Branch Constructs:: Labels, @code{GOTO}, @code{DO}, and @code{JOB}.
69: * Loop Constructs:: The @code{FOR} loop.
70: * Modular Programming:: Extrinsic functions and subroutines.
71: * Object-Oriented Programming:: Classes and objects in FreeM.
72: * Libraries:: System and user libraries.
73: * Sequential I/O:: Processing sequential files in FreeM.
74: * Network I/O:: Handling network sockets in FreeM.
75: * Extended Global References:: Accessing globals in non-default namespaces.
76: * Global Aliasing:: Defining alternate names for globals.
77: * Global Mappings:: Mapping global names to non-default namespaces.
78:
79: * Asynchronous Event Handling:: Handling asynchronous events in FreeM.
80: * Global Triggers:: Responding to global accesses in M code.
81: * Synchronous Event Handling:: Synchronous events in FreeM.
82:
83:
84: * GUI Programming with MWAPI:: Creating graphical interfaces in FreeM.
85:
86: * User-Defined Z Commands:: Adding your own Z commands to FreeM.
87: * User-Defined Z Functions:: Adding your own Z functions to FreeM.
88: * User-Defined SSVNs:: Adding your own SSVNs to FreeM.
89:
90: * Language Dialects:: Controlling FreeM standards compliance.
91:
92: * System Library Routines:: FreeM built-in library of M routines.
93:
94: * Interrupt Handling:: How FreeM handles interrupts.
95: * Error Processing:: How to handle errors in M program code.
96: * FreeM Error Codes:: Explanations of each FreeM error code.
97:
98: * System Configuration:: Configuring your FreeM installation.
99: * Accessing FreeM from C Programs:: How to use the mlib interface.
100:
101: * FreeM Administrator:: The fmadm system manager tool.
102: * FreeM Legacy Utilities:: FreeM legacy system manager utilities.
103: * FreeM VIEW Commands and Functions:: Getting and setting info about FreeM internals.
104: * Implementation Limits:: FreeM limitations.
105: * US-ASCII Character Set:: The US-ASCII character set.
106: * FreeM Project Coding Standards:: How to write code for submission to the FreeM project.
107:
108: * Index:: Complete index.
109: @end menu
110:
111: @node Introduction
112: @unnumbered Introduction
113:
1.36 snw 114: FreeM started its life as @emph{FreeMUMPS}, written for MS-DOS and ported to SCO UNIX by a mysterious individual going by the name of "Shalom ha-Ashkenaz". It was released to MUG Deutschland in 1998. In 1999, Ronald L. Fox ported FreeM to the Red Hat Linux 5 distribution of the GNU/Linux operating system. Thereafter, maintenance was taken over by the Generic Universal M Project, which changed its name first to Public Standard MUMPS and then by popular request to FreeM.
1.1 snw 115:
116: When GT.M was open-sourced in late 1999, FreeM and GUMP were essentially abandoned. L.D. Landis, the owner of the original GUMP SourceForge project, and one of FreeM's significant contributors, passed maintenance of FreeM and ownership of its SourceForge project to Serena Willis in 2014. At this point, FreeM would not compile or run on modern Linux systems, so steps were taken to remedy the most pressing issues in the codebase. Limitations on the terminal size (previously hard-coded to 80x25) were lifted, and new @code{$VIEW} functions were added to retrieve the terminal size information. @code{$X} and @code{$Y} intrinsic special variables were updated to support arbitrary terminal sizes, and FreeM was once again able to build and run.
117:
1.36 snw 118: In February of 2020, work began in earnest to build a development and support infrastructure for FreeM and begin the careful process of refining it into a more stable and robust application.
1.1 snw 119:
120: @section Production Readiness
121:
122: FreeM is not yet production-ready. There are several show-stopping bugs that preclude a general release for public use:
123:
124: @itemize @bullet
125:
126: @item
127: @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.
128:
129: @item
130: Server sockets are not yet implemented.
131:
132: @item
133: There are some situations that can result in segmentation faults and/or lock-ups.
134:
135: @item
136: In spite of our best efforts, this manual is not yet complete.
137:
138: @end itemize
139:
140: @section Contributors
141: Current contributors denoted with a @emph{+} following their name and role.
142: @cindex contributors, ha-Ashkenaz, Shalom
143: @cindex contributors, Best, John
144: @cindex contributors, Diamond, Jon
145: @cindex contributors, Fox, Ronald L.
146: @cindex contributors, Gerum, Winfried
147: @cindex contributors, Kreis, Greg
148: @cindex contributors, Landis, Larry
149: @cindex contributors, Milligan, Lloyd
150: @cindex contributors, Morris, Steve
151: @cindex contributors, Murray, John
152: @cindex contributors, Pastoors, Wilhelm
153: @cindex contributors, Schell, Kate
154: @cindex contributors, Schofield, Lyle
155: @cindex contributors, Stefanik, Jim
156: @cindex contributors, Trocha, Axel
157: @cindex contributors, Walters, Dick
158: @cindex contributors, Whitten, David
159: @cindex contributors, Wicksell, David
160: @cindex contributors, Willis, Serena
161: @cindex contributors, Zeck, Steve
162:
163: @itemize @bullet
164:
165: @item
166: Shalom ha-Ashkenaz (Original Implementer)
167:
168: @item
169: John Best (IBM i and OS/400)
170:
171: @item
172: Jon Diamond (Library, Utilities, Conformance)
173:
174: @item
175: Ronald L. Fox (Initial port to Red Hat 5/libc-6)
176:
177: @item
178: Winfried Gerum (Code, Advice, MTA coordination)
179:
180: @item
181: Greg Kreis (Hardhats coordination, Dependencies)
182:
183: @item
184: Larry Landis (Coordination, Code, Documentation)
185:
186: @item
187: Rick Marshall (Testing, MDC Conformance) @emph{+}
188:
189: @item
190: Lloyd Milligan (Code, Testing, Documentation)
191:
192: @item
193: Steve Morris (Code, Microsoft)
194:
195: @item
196: John Murray (Code, Conformance)
197:
198: @item
199: Wilhelm Pastoors (Testing, Documentation)
200:
201: @item
202: Kate Schell (Coordination, Conformance, MTA, MDC, Advice)
203:
204: @item
205: Lyle Schofield (Advice, Prioritization, Tracking, Project Management)
206:
207: @item
208: Jim Stefanik (GNU/Linux on s390x, IBM AIX, IBM z/OS)
209:
210: @item
211: Axel Trocha (Code, Utilities)
212:
213: @item
214: Dick Walters (Project Lead, Chief Coordinator, MTA)
215:
216: @item
217: David Whitten (QA Test Suite, MDC, Advice) @emph{+}
218:
219: @item
220: David Wicksell (Debugging, Code, Testing) @emph{+}
221:
222: @item
223: Serena Willis (Current Maintainer and Project Lead) @emph{+}
224:
225: @item
226: Steve Zeck (Code)
227:
228: @end itemize
1.36 snw 229:
230: @node Document Conventions
231: @chapter Document Conventions
232: @cindex document conventions
233: @cindex conventions
234:
235: @section Formatting Conventions
236:
237: This manual uses the following formatting conventions:
238: @itemize
239: @item Code examples, filesystem paths, and commands are presented in @code{monospace}
240: @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
241: @item New terminology is introduced in @emph{proportional italics}
242: @end itemize
243:
244: @section Definitions
245:
246: FreeM uses abbreviations for common language elements:
247:
248: @table @asis
249: @item @emph{$PREFIX}
250: Refers to the base filesystem location within which FreeM is installed. For most distribution methods of FreeM, @emph{$PREFIX} represents either @code{/} or @code{/usr/local}.
1.37 ! snw 251: @item @emph{dlabel}
! 252: Refers to a label in an M routine, beginning in the first column of the line. Can be a @emph{name} or an @emph{intlit}.
! 253: @item @emph{entryref}
! 254: Refers to an M routine entry point, denoted in the format @code{@emph{dlabel} [+@emph{intexpr}][^@emph{routine}]}.
1.36 snw 255: @item @emph{expr}
256: Refers to any expression. Often presented in the format @emph{expr V <type>}, where @emph{V} means @emph{giving}; e.g., @emph{expr V lvn} means @emph{expression giving local variable name}.
257: @item @emph{glvn}
258: Refers to the name of an M global, local, or structured system variable.
259: @item @emph{gvn}
260: Refers to the name of an M global variable.
261: @item @emph{intexpr}
262: Refers to an integer expression.
1.37 ! snw 263: @item @emph{intlit}
! 264: Refers to an integer literal.
1.36 snw 265: @item @emph{ISV}, @emph{isv}
266: Refers to an M intrinsic special variable; @code{$JOB} and @code{$IO} are examples of ISVs.
267: @item @emph{L}
268: Indicates a @emph{list} of the following item, e.g., @emph{L gvn} means @emph{list of global variable names}.
269: @item @emph{lvn}
270: Refers to the name of an M local variable.
1.37 ! snw 271: @item @emph{strlit}
! 272: Refers to an M string literal.
1.36 snw 273: @item @emph{ssvn}
274: Refers to the name of an M structured system variable.
275: @item @emph{tvexpr}
276: Refers to a truth-valued expression.
277: @end table
278:
1.1 snw 279: @node FreeM Invocation
280: @chapter FreeM Invocation
281: @cindex invocation, command-line
282: @cindex options, command-line
283:
284: @section Synopsis
285: @example
286: $ @command{./freem} [@emph{OPTIONS}...] [[-r <entryref>] | [--routine=<entryref>]]
287: @end example
288:
1.28 snw 289: When FreeM loads, it searches the @code{SYSTEM} namespace for the @code{%SYSINIT} routine, and begins executing it.
1.1 snw 290:
1.28 snw 291: 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 292:
293: @section %SYSINIT Routine
294:
1.36 snw 295: 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 296:
1.28 snw 297: 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 298:
299: @section Command-Line Options
1.22 snw 300: @cindex options, command-line
1.1 snw 301:
302: @table @asis
303:
304: @item @option{-d}, @option{--daemon}
1.22 snw 305: 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 306:
307: @item @option{-e}, @option{--environment}
308: Selects the environment to be used. If no environment is specified, @code{DEFAULT} is used.
309:
310: @item @option{-k}, @option{--nofork}
1.22 snw 311: 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 312:
313: @item @option{-S}, @option{--shmsize}
314: 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.
315:
316: @item @option{-c}, @option{--config}
317: Specify a configuration file other than @code{$PREFIX/etc/freem.conf}.
318:
319: @item @option{-h}, @option{--help}
320: Display a help message showing valid FreeM options.
321:
322: @item @option{-i}, @option{--import}
323: Causes your UNIX environment variables to be imported into FreeM's local symbol table.
324:
325: @item @option{-f}, @option{--filter}
326: Allows your M routines to be used as UNIX filters.
327:
328: @item @option{-n @emph{<namespace-name>}}, @option{--namespace=@emph{<namespace-name>}}
1.22 snw 329: Selects the FreeM namespace to be entered on startup. Must be defined in @file{/etc/<environment>/freem.conf}.
1.1 snw 330:
331: @item @option{-r @emph{<entryref>}}, @option{--routine=@emph{<entryref>}}
1.28 snw 332: Causes @code{<entryref>} to be executed at load, instead of @code{%SYSINIT}.
1.1 snw 333:
334: @item @option{--standard=@emph{<standard>}}
335: Sets the default FreeM dialect to use for new routine buffers.
336:
337: Valid values for @code{@emph{<standard>}} are as follows:
338:
339: @table @code
340: @item @code{M77}
341: Restricts FreeM to use only features specified by the 1977 M standard.
342: @item @code{M84}
343: Restricts FreeM to use only features specified by the 1984 M standard.
344: @item @code{M90}
345: Restricts FreeM to use only features specified by the 1990 M standard.
346: @item @code{M95}
347: Restricts FreeM to use only features specified by the 1995 M standard.
348: @item @code{MDS}
349: Restricts FreeM to use only features proposed by the Millennium Draft Standard.
350: @item @code{M5}
351: Restricts FreeM to use only features proposed by the upcoming M5 standard.
352: @item @code{FREEM}, @code{EXTENDED}
353: Removes all standards-based restrictions and allows full access to all FreeM features. This is the default value of @code{$DIALECT}.
354: @end table
355:
356: Please note that FreeM is not entirely standards-compliant, regardless of the value of @code{@emph{<standard>}}.
357:
358: @item @option{-v}, @option{--version}
359: Displays FreeM version information.
360:
361: @item @option{-x @emph{<mcode>}}, @option{--execute=@emph{<mcode>}}
1.22 snw 362: Executes M code @code{<mcode>} at startup.
1.1 snw 363:
364: @end table
365:
366: @section Using FreeM for Shell Scripting
367: @cindex routines, as shell scripts
368: @cindex shebang line
369: @cindex shell scripting
370:
371: 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.
372: The following example presumes that FreeM is installed at @file{/usr/local/bin/freem} and uses the @code{USER} namespace:
373:
374: @example
375: #!/usr/local/bin/freem
376: MYSCRIPT ;
377: SET ^$JOB($JOB,"NAMESPACE")="USER"
378: WRITE "This is output from an M routine used as a shell script.",!
379: Q
380: @end example
381:
382: 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.
383:
384: You will also need to set the script's permissions to @emph{executable} in order for this to work:
385:
386: @example
387: $ chmod +x @emph{myscript.m}
388: @end example
389:
1.22 snw 390: @node The FreeM Environment Daemon
391: @chapter The FreeM Environment Daemon
1.1 snw 392: @cindex daemon, freem
393:
1.22 snw 394: 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.
395:
396: One daemon process is required per FreeM environment, and can be started in the following ways, in order of preference:
1.1 snw 397:
1.22 snw 398: @example
399: $ sudo fmadm start environment [-e=<environment-name>]
400: @end example
1.1 snw 401:
402: @example
1.22 snw 403: $ freem --daemon [--nofork] [--environment=<environment-name>] [--shmsize=<bytes>]
1.1 snw 404: @end example
405:
406: 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.
407:
408: 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.
409:
410: 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.
411:
412: Attempting to start a FreeM interpreter process without a daemon running with the same environment name will result in an error.
413:
414: @node The FreeM Direct-Mode Environment
415: @chapter The FreeM Direct-Mode Environment
416: @cindex command line interface
417: @cindex direct mode
418: @cindex execution, interactive
419: @cindex modes, programmer
420:
421:
422: 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>}}:
423:
424: @example
1.32 snw 425: Coherent Logic Development FreeM version 0.64.0-rc1 (x86_64-pc-linux-gnu)
1.1 snw 426: Copyright (C) 2014, 2020, 2021 Coherent Logic Development LLC
427:
428:
429: USER>
430: @end example
431:
1.25 snw 432: 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{$TLEVEL}}:
1.1 snw 433:
434: @example
1.22 snw 435: TL1:DEFAULT.USER>
1.1 snw 436: @end example
437:
438: In the above example, @code{TL1} indicates that @code{@ref{$TLEVEL}} is currently @emph{1}.
439:
440: @section Direct-Mode Commands
441:
442: When you are in direct mode, in addition to M commands, a number of internal commands are available to help developers be more productive:
443:
444: @table @asis
445:
446: @item @command{?}
447: Accesses FreeM online help. Requires GNU @command{info(1)} to be installed on your local system.
448:
449: @item @command{events}
450: Writes a list of @emph{event classes} and their @code{ABLOCK} counts:
451:
452: @example
1.22 snw 453: DEFAULT.USER> events
1.1 snw 454:
455: Event Class Processing Mode ABLOCK Count
456: ----------- --------------- ------------
457: COMM Disabled 0
458: HALT Disabled 0
459: IPC Disabled 0
460: INTERRUPT Disabled 0
461: POWER Disabled 0
462: TIMER Disabled 0
463: USER Disabled 0
464: WAPI Disabled 0
465: TRIGGER Disabled 0
466: @end example
467:
468:
469: @anchor{trantab}
470: @item @command{trantab}
471: Displays information about any uncommitted transactions currently in-flight for this process.
472:
1.22 snw 473: @anchor{glstat}
474: @item @command{trantab}
475: Displays statistics about globals that have been opened in the current FreeM process.
476:
1.1 snw 477: @anchor{jobtab}
478: @item @command{jobtab}
479: Displays a summary of the FreeM job table.
480:
481: @anchor{locktab}
482: @item @command{locktab}
483: Displays a list of @code{LOCK}s held in the current environment.
484:
485: @anchor{rbuf}
486: @item @command{rbuf}
487: Lists the status of all FreeM routine buffers.
488:
489: @anchor{wh}
490: @item @command{wh}
491: Forces an immediate flush of this process's @code{readline} history buffer to disk.
492:
493: @anchor{shmstat}
494: @item @command{shmstat}
495: Displays the configuration of FreeM shared memory. Intended only for advanced debugging of the FreeM environment.
496:
497: @anchor{shmpages}
498: @item @command{shmpages}
499: Lists the status of each FreeM shared memory page. Intended only for advanced debugging of the FreeM environment.
500:
501: @anchor{history}
502: @item @command{history}
503: Prints a list of all the direct-mode commands you have entered across all sessions.
504:
505: @anchor{rcl}
506: @item @command{rcl @emph{<history-index>}}
507: 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.
508:
509: @item @command{!!}
510: Launches a subshell within the FreeM direct mode, allowing the user to run operating system commands.
511:
512: @example
1.22 snw 513: DEFAULT.USER> !!
1.1 snw 514:
515: Type Ctrl-D to exit from the shell
516: $ uname -a
517: Linux hesperos 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux
518: $ exit
519:
1.22 snw 520: DEFAULT.USER>
1.1 snw 521: @end example
522:
523: @item @command{!@emph{<external-command>}}
1.28 snw 524: 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 525:
526: 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>}.
527:
528: 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")}.
529:
530: 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}.
531:
532: @end table
533:
534: @cindex HALT, in direct-mode
535: 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:
536:
537: @example
1.22 snw 538: DEFAULT.USER> TSTART
1.1 snw 539:
540:
1.22 snw 541: TL1:DEFAULT.USER> SET ^MYGLOBAL=1
1.1 snw 542:
543:
1.22 snw 544: TL1:DEFAULT.USER> HALT
1.1 snw 545:
546: UNCOMMITTED TRANSACTIONS EXIST:
547:
548: $TLEVEL 1*
549: Operations for Transaction ID: k8xj1de
550: 1: action = 0 key = ^MYGLOBAL data = 1
551:
552: Would you like to c)ommit or r)ollback the above transactions and their operations? ($TLEVEL = 1) r
553:
554:
555: Transactions have been rolled back.
556: @end example
557:
558: In the above example, the user selected @code{r} to rollback the single pending transaction.
559:
560: @section REPL Functionality
561: @cindex REPL, direct-mode
562:
563: FreeM direct mode allows you to enter M expressions directly from the direct-mode prompt, as long as they begin with a number:
564:
565: @example
1.22 snw 566: DEFAULT.USER> S DENOM=10
1.1 snw 567:
568:
1.22 snw 569: DEFAULT.USER> 100/DENOM
1.1 snw 570:
571: 10
1.22 snw 572: DEFAULT.USER>
1.1 snw 573: @end example
574:
575: Such expressions will be immediately evaluated, and the result printed on @code{@ref{$IO}}.
576:
1.36 snw 577: @node Debugging
578: @chapter Debugging
579: @cindex debugging
580:
581: @section Debugging Synopsis
582: 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.
583:
584: If you would like to enter the debugger automatically each time an error is encountered, add the following to your @code{LCLINIT} routine:
585:
586: @example
587: S $ETR="B ""DEBUG"""
588: @end example
589:
590: @section Debugging Commands
591: The debugger uses its own unique command language, where M commands are unavailable. Commands are as follows:
592:
593: @table @asis
594: @item @code{exit}, @code{quit}
595: Exits the debugger and returns to direct mode or normal program execution.
596: @item @code{e} @emph{glvn}, @code{examine} @emph{glvn}
597: Prints the value of @emph{glvn} to the terminal.
598: @item @code{t}, @code{trace}
599: 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.
600: @item @code{s}, @code{step}
601: Single-steps through FreeM code command-by-command.
602: @item @code{n}, @code{next}
603: Single-steps through FreeM code line-by-line.
604: @item @code{c}, @code{cont}, @code{continue}
605: Resumes normal program execution, disabling single-step mode.
606: @item @code{bt}, @code{backtrace}
607: Produces a stack trace.
608: @item @code{h}, @code{halt}
609: Halts the process being debugged and returns control to the operating system.
610: @item @code{w [[+|-|?]@emph{<glvn>}]}, @code{watch [[+|-|?]@emph{<glvn>}]}
611: 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>}.
612: @end table
613:
1.1 snw 614: @node Directives
615: @chapter Directives
616: @cindex directives
617:
618: 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.
619:
620: The format of a directive is @code{;%@emph{<directive-name>}}, where @code{@emph{<directive-name>}} is one of the directives listed below.
621:
622: @menu
623: * %DIALECT:: Sets the M dialect in effect.
624: @end menu
625:
626: @anchor{%DIALECT}
627: @section %DIALECT
628: @cindex %DIALECT
629: @cindex directives, %DIALECT
630:
631: Sets the M dialect in effect for the current routine buffer; also sets the @code{$DIALECT} special variable to match. See also @ref{$DIALECT}.
632:
633: @emph{Syntax}
634:
635: @example
636: ;%DIALECT @emph{<dialect>}
637: @end example
638:
639: Valid values for @code{@emph{<dialect>}} are as follows:
640:
641: @table @code
642: @item @code{M77}
643: Restricts FreeM to use only features specified by the 1977 M standard.
644: @item @code{M84}
645: Restricts FreeM to use only features specified by the 1984 M standard.
646: @item @code{M90}
647: Restricts FreeM to use only features specified by the 1990 M standard.
648: @item @code{M95}
649: Restricts FreeM to use only features specified by the 1995 M standard.
650: @item @code{MDS}
651: Restricts FreeM to use only features proposed by the Millennium Draft Standard.
652: @item @code{M5}
653: Restricts FreeM to use only features proposed by the upcoming M5 standard.
654: @item @code{FREEM}, @code{EXTENDED}
655: Removes all standards-based restrictions and allows full access to all FreeM features. This is the default value of @code{%DIALECT}.
656: @end table
657:
658: Please note that FreeM is not entirely standards-compliant, regardless of the value of @code{%DIALECT}.
659:
660:
661: @node Intrinsic Special Variables
662: @chapter Intrinsic Special Variables
663: @cindex variables, intrinsic special
664:
665: @menu
666: * $DEVICE:: $IO device status.
667: * $DIALECT:: Current M dialect.
668: * $ECODE:: Latest M error code.
669: * $ESTACK:: Error stack info.
670: * $ETRAP:: Standard error handler code.
671: * $HOROLOG:: Current date and time.
672: * $IO:: Current I/O device.
673: * $JOB:: PID of current process.
674: * $KEY:: Characters terminating last @code{READ} command.
675: * $PDISPLAY:: Current primary MWAPI display.
676: * $PRINCIPAL:: I/O channel of terminal.
677: * $REFERENCE:: Most recent global reference.
678: * $QUIT:: Whether a @code{QUIT} command requires an argument in the current execution context.
679: * $STACK:: Current program execution stack level.
680: * $STORAGE:: Number of bytes available in the heap.
681: * $SYSTEM:: MDC system ID of FreeM.
682: * $TEST:: Truth value of last conditional expression or result of certain @code{LOCK} operations.
683: * $TLEVEL:: Current level of transaction nesting.
684: * $WITH:: Current variable prefix set by @code{WITH} command.
685: * $X:: Current horizontal screen position.
686: * $Y:: Current vertical screen position.
687: * $ZA:: Current position of file on @code{$IO}.
688: * $ZB:: Most recent keystroke.
689: * $ZCONTROLC:: Control-C handling flag.
690: * $ZDATE:: Current date in locale-specific representation.
691: * $ZERROR:: Last error message.
692: * $ZHOROLOG:: Date and time, including milliseconds.
693: * $ZINRPT:: State of the interrupt enable/disable flag.
694: * $ZJOB:: PID of parent process, if applicable.
695: * $ZLOCAL:: Last local variable reference.
696: * $ZNAME:: Name of current M routine.
697: * $ZPRECISION:: Digits of arithmetical precision.
698: * $ZREFERENCE:: Last gvn referenced.
699: * $ZSYSTEM:: Return value of last external command.
700: * $ZTIME:: Current time in locale-specific representation.
701: * $ZTRAP:: Entryref to be executed on error condition.
702: * $ZUT:: Microseconds since the UNIX epoch.
703: * $ZVERSION:: Version of FreeM and GNU host triplet.
704: @end menu
705:
706: @node $DEVICE
707: @section $DEVICE
708: @cindex $DEVICE
709: @cindex intrinsic special variables, $DEVICE
710:
711: Returns the status of the device currently in use.
712:
713: If @code{$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.
714:
715: @node $DIALECT
716: @section $DIALECT
717: @cindex $DIALECT
718: @cindex intrinsic special variables, $DIALECT
719:
720: Returns or sets the language dialect of the current routine.
721:
722: Valid values for @code{$DIALECT} are as follows:
723:
724: @table @code
725: @item @code{M77}
726: Restricts FreeM to use only features specified by the 1977 M standard.
727: @item @code{M84}
728: Restricts FreeM to use only features specified by the 1984 M standard.
729: @item @code{M90}
730: Restricts FreeM to use only features specified by the 1990 M standard.
731: @item @code{M95}
732: Restricts FreeM to use only features specified by the 1995 M standard.
733: @item @code{MDS}
734: Restricts FreeM to use only features proposed by the Millennium Draft Standard.
735: @item @code{M5}
736: Restricts FreeM to use only features proposed by the upcoming M5 standard.
737: @item @code{FREEM}, @code{EXTENDED}
738: Removes all standards-based restrictions and allows full access to all FreeM features. This is the default value of @code{$DIALECT}.
739: @end table
740:
741: Please note that FreeM is not entirely standards-compliant, regardless of the value of @code{$DIALECT}.
742:
743: @node $ECODE
744: @section $ECODE
745: @cindex $ECODE
746: @cindex intrinsic special variables, $ECODE
747:
748: Returns a comma-delimited list of error conditions currently present, and is writable. An empty @code{$ECODE} indicates no errors.
749:
1.28 snw 750: Writing a value in the format @code{,<error-code>,} into @code{$ECODE} will raise that error condition.
751:
1.1 snw 752: @node $ESTACK
753: @section $ESTACK
754: @cindex $ESTACK
755: @cindex intrinsic special variables, $ESTACK
756:
757: Returns the depth of the program execution stack since the last time @code{$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.
758:
759: @node $ETRAP
760: @section $ETRAP
761: @cindex $ETRAP
762: @cindex intrinsic special variables, $ETRAP
763:
764: Sets or retrieves the M code that is run when an error is encountered or @code{@ref{$ECODE}} is set to a non-blank value. @code{$ETRAP} code executes when @code{$ECODE} becomes non-blank.
765:
766:
767: @node $HOROLOG
768: @section $HOROLOG
769: @cindex $HOROLOG
770: @cindex intrinsic special variables, $HOROLOG
771:
772: Returns a string containing the current date and time as @code{<days>,<seconds>}, where @code{<days>} represents the number of days since the M epoch (midnight on 31 December 1840),
773: and @code{<seconds>} represents the number of seconds since the most recent midnight.
774:
775: @cartouche
776: @quotation
777: @emph{FreeM Extension}
778:
779: In FreeM, @code{$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.
780: @end quotation
781: @end cartouche
782:
783: @node $IO
784: @section $IO
785: @cindex $IO
786: @cindex intrinsic special variables, $IO
787:
788: Represents the current input/output device. Read-only.
789:
790: @node $JOB
791: @section $JOB
792: @cindex $JOB
793: @cindex intrinsic special variables, $JOB
794:
795: Represents the process ID of the FreeM instance currently in use.
796:
797: @node $KEY
798: @section $KEY
799: @cindex $KEY
800: @cindex intrinsic special variables, $KEY
801:
802: Represents the sequence of control characters that terminated the last @code{@ref{READ}} command on @code{@ref{$IO}}.
803:
804: @node $PDISPLAY
805: @section $PDISPLAY
806: @cindex $PDISPLAY
807: @cindex intrinsic special variables, $PDISPLAY
808:
809: Represents the current principal display for M Windowing API operations. Commonly used as an index into the @code{@ref{^$DISPLAY}} structured system variable.
810:
811: @node $PRINCIPAL
812: @section $PRINCIPAL
813: @cindex $PRINCIPAL
814: @cindex intrinsic special variables, $PRINCIPAL
815:
816: Represents the primary input/output device. Usually a terminal or virtual terminal.
817:
818: @node $REFERENCE
819: @section $REFERENCE
820: @cindex $REFERENCE
821: @cindex intrinsic special variables, $REFERENCE
822:
823: Returns the last @emph{glvn} referenced. Can be @code{@ref{SET}}, and also stacked with @code{@ref{NEW}}.
824:
825: @node $QUIT
826: @section $QUIT
827: @cindex $QUIT
828: @cindex intrinsic special variables, $QUIT
829:
830: If the current execution context was invoked as an extrinsic function, @code{$QUIT} returns @emph{1}. Otherwise, returns @emph{0}.
831:
832: When @code{$QUIT} returns @emph{1}, a subsequent @code{@ref{QUIT}} command must have an argument.
833:
834: @node $STACK
835: @section $STACK
836: @cindex $STACK
837: @cindex intrinsic special variables, $STACK
838:
839: Represents the current stack level.
840:
841: @node $STORAGE
842: @section $STORAGE
843: @cindex $STORAGE
844: @cindex intrinsic special variables, $STORAGE
845:
846: Represents the number of bytes of free space available in FreeM's heap.
847:
848: @node $SYSTEM
849: @section $SYSTEM
850: @cindex $SYSTEM
851: @cindex intrinsic special variables, $SYSTEM
852:
853: Returns the MDC system ID of FreeM, as well as the environment ID of the current environment.
854:
855: @node $TEST
856: @section $TEST
857: @cindex $TEST
858: @cindex intrinsic special variables, $TEST
859:
860: @code{$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}.
861:
862: @code{$TEST} is implicitly @code{NEW}ed when entering a new stack frame for extrinsic functions and argumentless @code{@ref{DO}}. @code{$TEST}
863: is @emph{not} implicitly @code{NEW}ed when a new stack frame is entered with an argumented @code{DO}.
864:
865: 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.
866:
867: @node $TLEVEL
868: @section $TLEVEL
869: @cindex $TLEVEL
870: @cindex intrinsic special variables, $TLEVEL
871:
872: Returns a numeric value indicating the current level of transaction nesting in the process. When @code{$TLEVEL} is greater than @emph{0},
873: uncommitted transactions exist.
874:
875: @node $WITH
876: @section $WITH
877: @cindex $WITH
878: @cindex intrinsic special variables, $WITH
879:
880: Returns the variable prefix set by the @code{@ref{WITH}} command.
881:
882: @node $X
883: @section $X
884: @cindex $X
885: @cindex intrinsic special variables, $X
886:
887: Represents the current column position of the FreeM cursor.
888:
889: @cartouche
890: @quotation
891: In FreeM, setting @code{$X} will move the FreeM cursor.
892: @end quotation
893: @end cartouche
894:
895:
896: @node $Y
897: @section $Y
898: @cindex $Y
899: @cindex intrinsic special variables, $Y
900:
901: Represents the current row position of the FreeM cursor.
902:
903: @cartouche
904: @quotation
905: In FreeM, setting @code{$Y} will move the FreeM cursor.
906: @end quotation
907: @end cartouche
908:
909:
910: @node $ZA
911: @section $ZA
912: @cindex $ZA
913: @cindex intrinsic special variables, $ZA
914: @cindex intrinsic special variables, implementation-specific
915:
916: On the @code{HOME} device, always @code{0}. On other devices, returns the current position of the file opened on I/O channel @code{@ref{$IO}}.
917:
918: @node $ZB
919: @section $ZB
920: @cindex $ZB
921: @cindex intrinsic special variables, $ZB
922: @cindex intrinsic special variables, implementation-specific
923:
924: Represents the last keystroke.
925:
926: @node $ZCONTROLC
927: @section $ZCONTROLC
928: @cindex $ZCONTROLC
929: @cindex intrinsic special variables, $ZCONTROLC
930: @cindex intrinsic special variables, implementation-specific
931:
932: Returns the status of the Ctrl-C flag and resets it to @emph{false}.
933:
934: @node $ZDATE
935: @section $ZDATE
936: @cindex $ZDATE
937: @cindex intrinsic special variables, $ZDATE
938: @cindex intrinsic special variables, implementation-specific
939:
940: Returns the current date, in the preferred representation for the current system locale.
941:
942: @node $ZERROR
943: @section $ZERROR
944: @cindex $ZERROR
945: @cindex intrinsic special variables, $ZERROR
946: @cindex intrinsic special variables, implementation-specific
947:
948: Returns the last error message.
949:
950: @node $ZHOROLOG
951: @section $ZHOROLOG
952: @cindex $ZHOROLOG
953: @cindex intrinsic special variables, $ZHOROLOG
954: @cindex intrinsic special variables, implementation-specific
955:
956: Output @code{@ref{$HOROLOG}}-style time, with the addition of milliseconds.
957:
958: @node $ZINRPT
959: @section $ZINRPT
960: @cindex $ZINRPT
961: @cindex intrinsic special variables, $ZINRPT
962: @cindex intrinsic special variables, implementation-specific
963:
964: Gets or sets the interrupt enable/disable flag.
965:
966: @node $ZJOB
967: @section $ZJOB
968: @cindex $ZJOB
969: @cindex intrinsic special variables, $ZJOB
970: @cindex intrinsic special variables, implementation-specific
971:
972: Returns the @code{@ref{$JOB}} value of the parent process if the current process was started by a @code{@ref{JOB}} command. Otherwise, returns an empty string.
973:
974: @node $ZLOCAL
975: @section $ZLOCAL
976: @cindex $ZLOCAL
977: @cindex intrinsic special variables, $ZLOCAL
978: @cindex intrinsic special variables, implementation-specific
979:
980: Returns the last local variable referenced.
981:
982: @node $ZNAME
983: @section $ZNAME
984: @cindex $ZNAME
985: @cindex intrinsic special variables, $ZNAME
986: @cindex intrinsic special variables, implementation-specific
987:
988: Returns the name of the current routine.
989:
990: @node $ZPRECISION
991: @section $ZPRECISION
992: @cindex $ZPRECISION
993: @cindex intrinsic special variables, $ZPRECISION
994: @cindex intrinsic special variables, implementation-specific
995:
996: Gets or sets the number of digits of numeric precision used for fixed-point decimal arithmetic. If @code{^$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{$ZPRECISION} defaults to 100 digits, with a maximum of 20,000 digits.
997:
998: @xref{^$JOB}.
999:
1000: @node $ZREFERENCE
1001: @section $ZREFERENCE
1002: @cindex $ZREFERENCE
1003: @cindex intrinsic special variables, $ZREFERENCE
1004: @cindex intrinsic special variables, implementation-specific
1005:
1006: Returns the last @emph{gvn} referenced.
1007:
1008: @node $ZSYSTEM
1009: @section $ZSYSTEM
1010: @cindex $ZSYSTEM
1011: @cindex intrinsic special variables, $ZSYSTEM
1012: @cindex intrinsic special variables, implementation-specific
1013:
1014: Represents the return value of the last external command run with @code{!}.
1015:
1016: @node $ZTIME
1017: @section $ZTIME
1018: @cindex $ZTIME
1019: @cindex intrinsic special variables, $ZTIME
1020: @cindex intrinsic special variables, implementation-specific
1021:
1022: Returns the system time in the preferred representation for the current system locale.
1023:
1024: @node $ZTRAP
1025: @section $ZTRAP
1026: @cindex $ZTRAP
1027: @cindex intrinsic special variables, $ZTRAP
1028: @cindex intrinsic special variables, implementation-specific
1029:
1030: Sets or retrieves the entryref to be executed when an M program execution error occurs under FreeM-style or DSM 2.0-style error processing.
1031:
1032: In FreeM-style error processing, @code{$ZTRAP} is specific to each program execution stack level.
1033:
1034: In DSM 2.0-style error processing, @code{$ZTRAP} is the same for all program execution stack levels.
1035:
1036: When FreeM encounters an error, if @code{$ZTRAP} is nonempty and @code{$ETRAP} is empty, FreeM will perform an implicit @code{@ref{GOTO}} to the entryref indicated in @code{$ZTRAP}.
1037:
1038: 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.
1039:
1040: @node $ZUT
1041: @section $ZUT
1042: @cindex $ZUT
1043: @cindex intrinsic special variables, $ZUT
1044: @cindex intrinsic special variables, implementation-specific
1045:
1046: Returns the number of microseconds elapsed since the UNIX epoch (Jan 1, 1970 0:00:00).
1047:
1048: @node $ZVERSION
1049: @section $ZVERSION
1050: @cindex $ZVERSION
1051: @cindex intrinsic special variables, $ZVERSION
1052: @cindex intrinsic special variables, implementation-specific
1053:
1054: Returns the version of FreeM in use, as well as the GNU host triplet for the current FreeM build.
1055:
1056: See @emph{https://wiki.osdev.org/Target_Triplet}.
1057:
1058: @node Intrinsic Functions
1059: @chapter Intrinsic Functions
1060:
1061: @menu
1062: * $ASCII():: Return ASCII code for character in string.
1063: * $CHAR():: Return character for one or more ASCII codes.
1064: * $DATA():: Retrieve definition and characteristics of array node.
1065: * $EXTRACT():: Return a substring of a string.
1066: * $FIND():: Find position of substring within string.
1067: * $FNUMBER():: Format a number according to formatting codes.
1068: * $GET():: Return value of glvn or a default if undefined.
1069: * $INSTANCEOF():: Determine if lvn is an instance of a class.
1070: * $JUSTIFY():: Right-justify a string based on specified length.
1071: * $LENGTH():: Return length or delimiter-based piece count of string.
1072: * $NAME():: Return canonical name from string representation of glvn.
1073: * $NEXT():: Return next numeric subscript following given glvn.
1074: * $ORDER():: Return next subscript at same level of specified glvn.
1075: * $PIECE():: Return one or more delimited pieces of a string.
1076: * $QLENGTH():: Return subscript count of glvn.
1077: * $QSUBSCRIPT():: Return a specified subscript from glvn.
1078: * $QUERY():: Return next subscript of specified glvn.
1079: * $RANDOM():: Return pseudorandom integer up to a maximum value.
1080: * $REVERSE():: Reverse a string.
1081: * $SELECT():: Return value from first true condition in list of expressions.
1082: * $STACK():: Return information about the program stack.
1083: * $TEXT():: Return line of code from a routine.
1084: * $TRANSLATE():: Substitute specified characters in a string.
1085: * $TYPE():: Return class of the specified lvn.
1086: * $VIEW():: Retrieve implementation-specific information.
1087: * $ZBOOLEAN():: Perform boolean operations on numeric arguments.
1088: * $ZCALL():: Unknown.
1089: * $ZCRC():: Generate checksum of a string argument.
1090: * $ZDATA():: Unknown.
1091: * $ZDATE():: Convert @code{@ref{$HOROLOG}} string into human-readable date.
1092: * $ZEDIT():: Unknown.
1093: * $ZHOROLOG():: Convert date/time values to @code{@ref{$HOROLOG}} format.
1094: * $ZKEY():: Unknown.
1095: * $ZLENGTH():: Unknown.
1096: * $ZLSD():: Compute Levenshtein distance between two arguments.
1097: * $ZM():: Unknown.
1098: * $ZNAME():: Unknown.
1099: * $ZNEXT():: Unknown.
1100: * $ZORDER():: Unknown.
1101: * $ZPIECE():: Unknown.
1102: * $ZPREVIOUS():: Unknown.
1103: * $ZREPLACE():: Replace all instances of a substring within a string.
1104: * $ZSYNTAX():: Perform syntax check on string argument.
1105: * $ZTIME():: Convert a @code{@ref{$HOROLOG}} string into human-readable time.
1106: @end menu
1107:
1108: @node $ASCII()
1109: @section $ASCII
1110: @cindex $ASCII
1111: @cindex intrinsic functions, $ASCII
1112:
1113: Returns the ASCII code (in decimal) for one character in a string.
1114:
1115: @example
1116: SET RESULT=$ASCII(@emph{<string>}[,@emph{<index>}])
1117: @end example
1118:
1119:
1120: 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>}.
1121:
1122: @node $CHAR()
1123: @section $CHAR
1124: @cindex $CHAR
1125: @cindex intrinsic functions, $CHAR
1126:
1127: Returns a string of characters corresponding to a list of ASCII codes.
1128:
1129: @example
1130: SET RESULT=$CHAR(@emph{<ascii-code>}[,@emph{<ascii-code>},...])
1131: @end example
1132:
1133: @node $DATA()
1134: @section $DATA
1135: @cindex $DATA
1136: @cindex intrinsic functions, $DATA
1137:
1138: Returns a numeric value 0, 1, 10, or 11, depending on whether a referenced node is defined, has data, or has children:
1139:
1140: @example
1141: SET RESULT=$DATA(@emph{<node>})
1142: @end example
1143:
1144: The return values are as follows:
1145:
1146: @example
1147: 0: @emph{<node>} is undefined
1148: 1: @emph{<node>} has data but no children
1149: 10: @emph{<node>} has children but no data
1150: 11: @emph{<node>} has children and data
1151: @end example
1152:
1153: @node $EXTRACT()
1154: @section $EXTRACT
1155: @cindex $EXTRACT
1156: @cindex intrinsic functions, $EXTRACT
1157:
1158: Extracts a substring of a string.
1159:
1160: The first argument is the source string.
1161:
1162: The optional second argument specifies the starting position of the substring to extract, and defaults to @code{1}.
1163:
1164: The optional third argument specifies the ending position of the substring to extract, and defaults to the value of the second argument, or @code{1}.
1165:
1166: This example will extract the string @emph{FreeM} into the local variable @code{M}.
1167:
1168: @example
1169: SET NAME="FreeM is the best!"
1170: SET M=$EXTRACT(NAME,1,5)
1171: @end example
1172:
1173: It is also possible to use @code{$EXTRACT} on the left-hand side of a @code{SET} assignment in order to modify a substring:
1174:
1175: @example
1.22 snw 1176: DEFAULT.USER> SET FOO="ABCDEFG"
1.1 snw 1177:
1178:
1.22 snw 1179: DEFAULT.USER> SET $EXTRACT(FOO,1,3)="XYZ"
1.1 snw 1180:
1181:
1.22 snw 1182: DEFAULT.USER> WRITE FOO
1.1 snw 1183:
1184: XYZDEFG
1185: @end example
1186:
1187: @node $FIND()
1188: @section $FIND
1189: @cindex $FIND
1190: @cindex intrinsic functions, $FIND
1191:
1192: Finds the character immediately following the first occurence of a substring within a string.
1193:
1194: The first argument is the source string.
1195:
1196: The second argument is the substring to be located.
1197:
1198: The optional third argument indicates the position within the source string at which to begin searching.
1199:
1200: @node $FNUMBER()
1201: @section $FNUMBER
1202: @cindex $FNUMBER
1203: @cindex intrinsic functions, $FNUMBER
1204:
1205: Formats a number according to a particular set of formatting codes.
1206:
1207: The first argument is the number to format.
1208:
1.22 snw 1209: The second argument is the series of formatting codes:
1210:
1211: @table @asis
1212: @item 'P' or 'p'
1213: Will display negative numbers within parentheses instead of showing a minus sign.
1214: @item , (comma)
1215: Will add commas as thousands separators.
1216: @item +
1217: Will include a plus sign for positive numbers. Not compatible with 'P' or 'p'.
1218: @item -
1219: Will remove the minus sign from negative numbers. Not compatible with 'p' or 'P'.
1220: @item 't' or 'T'
1221: Will place the sign after the number instead of before the number.
1.23 snw 1222: @end table
1.22 snw 1223:
1224: 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 1225:
1226: @node $GET()
1227: @section $GET
1228: @cindex $GET
1229: @cindex intrinsic functions, $GET
1230:
1231: Returns the value of a local, global, or SSVN if the specified item is defined, or a default value otherwise.
1232:
1233: The first argument is the local, global, or SSVN to be examined.
1234:
1235: The optional second argument is the default value to be returned if the referenced item is undefined, and defaults to the empty string.
1236:
1237: @node $INSTANCEOF()
1238: @section $INSTANCEOF
1239: @cindex $INSTANCEOF
1240: @cindex intrinsic functions, $INSTANCEOF
1241: @cindex object functions, $INSTANCEOF
1242:
1243: Returns @code{1} if the specified @emph{lvn} is an instance of class @emph{class}, or @code{0} otherwise.
1244:
1245: The first argument is a string representing a valid FreeM local variable.
1246:
1247: The second argument is a string representing a valid FreeM class.
1248:
1249: @example
1.22 snw 1250: DEFAULT.USER> N STR=$$^%STRING
1.1 snw 1251:
1.22 snw 1252: DEFAULT.USER> W $INSTANCEOF("STR","^%STRING")
1.1 snw 1253: 1
1254: @end example
1255:
1256: @node $JUSTIFY()
1257: @section $JUSTIFY
1258: @cindex $JUSTIFY
1259: @cindex intrinsic functions, $JUSTIFY
1260:
1261: Right-justifies a string based on a specified fixed length.
1262:
1263: The first argument is the source string.
1264:
1265: The second argument is the character length of the output.
1266:
1267: 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.
1268:
1269: @node $LENGTH()
1270: @section $LENGTH
1271: @cindex $LENGTH
1272: @cindex intrinsic functions, $LENGTH
1273:
1274: 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()}}).
1275:
1276: The first argument is the source string.
1277:
1278: 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.
1279:
1280: @node $NAME()
1281: @section $NAME
1282: @cindex $NAME
1283: @cindex intrinsic functions, $NAME
1284:
1285: Returns the canonical name reference along with some or all of its subscripts.
1286:
1287: The first argument is the source name.
1288:
1289: The optional second argument indicates the maximum subscript count to be returned, and defaults to the subscript count of the source name.
1290:
1291: @node $NEXT()
1292: @section $NEXT
1293: @cindex $NEXT
1294: @cindex intrinsic functions, $NEXT
1295:
1.25 snw 1296: Deprecated. Use @code{$ORDER} instead.
1297:
1.1 snw 1298: @node $ORDER()
1299: @section $ORDER
1300: @cindex $ORDER
1301: @cindex intrinsic functions, $ORDER
1302:
1.25 snw 1303: Returns the previous subscript or next subscript in a local, global, or a subset of structured system variables.
1304:
1305: The first argument is the subscripted local, global, or SSVN.
1306:
1307: The optional second argument can be @code{1} to retrieve the next subscript, or @code{-1} to return the previous.
1308:
1.1 snw 1309: @node $PIECE()
1310: @section $PIECE
1311: @cindex $PIECE
1312: @cindex intrinsic functions, $PIECE
1313:
1314: @emph{Syntax}
1315:
1316: @code{$PIECE(@emph{s},@emph{d}[,@emph{n}[,@emph{end}]])}
1317:
1318: Accesses the @code{n}th through @code{end} @code{d}-delimited pieces of string @code{s}.
1319:
1320: The first argument is the string to be evaluated.
1321:
1322: The second argument is the delimiter to be used.
1323:
1324: The optional third argument is the first @code{d}-delimited piece to access, and defaults to @code{1}.
1325:
1326: The optional fourth argument is the final @code{d}-delimited piece to access, and defaults to the value of the third argument (@code{n}).
1327:
1328: 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:
1329:
1330: @example
1.28 snw 1331: ; ^snw="this^is^a^piece"
1332: SET $PIECE(^snw,"^",2)="isn't" ; => "this^isn't^a^piece"
1.1 snw 1333: @end example
1334:
1335: @node $QLENGTH()
1336: @section $QLENGTH
1337: @cindex $QLENGTH
1338: @cindex intrinsic functions, $QLENGTH
1339:
1340: @emph{Syntax}
1341:
1342: @example
1343: @code{$QLENGTH(@emph{expr V glvn})}
1344: @end example
1345:
1346: Returns the number of subscripts in @emph{glvn}.
1347:
1348: @emph{Example}
1349: @example
1350: @code{SET SUBCT=$QLENGTH("^GBL(1,2,3)") ; => 3}
1351: @end example
1352:
1353: @node $QSUBSCRIPT()
1354: @section $QSUBSCRIPT
1355: @cindex $QSUBSCRIPT
1356: @cindex intrinsic functions, $QSUBSCRIPT
1357:
1358: @emph{Syntax}
1359:
1360: @example
1361: @code{$QSUBSCRIPT(@emph{expr V glvn},@emph{expr V n})}
1362: @end example
1363:
1.28 snw 1364: In the RHS form, returns the @emph{n}th subscript of @emph{glvn}.
1.1 snw 1365:
1366: @emph{Example}
1367:
1368: @example
1369: @code{SET SUB=$QSUBSCRIPT("^GBL(1,2,3)",2) ; => 2}
1370: @end example
1371:
1.28 snw 1372: @emph{Syntax}
1373:
1374: @example
1375: @code{SET $QSUBSCRIPT(@emph{expr V glvn},@emph{expr V n})=@emph{expr} ; => ^GBL(1,4,3)}
1376: @end example
1377:
1378: In the LHS form, sets the @emph{n}th subscript of @emph{glvn} to @emph{expr}.
1379:
1.1 snw 1380: @node $QUERY()
1381: @section $QUERY
1382: @cindex $QUERY
1383: @cindex intrinsic functions, $QUERY
1384:
1385: Returns the next subscripted reference in a global.
1386:
1387: @emph{Syntax}
1388:
1389: @example
1390: @code{$QUERY(@emph{glvn})}
1391: @end example
1392:
1393: @emph{Example}
1394:
1395: We will assume the following data structure exists:
1396: @example
1.28 snw 1397: ^snw(1)=1
1398: ^snw(1,2)="foo"
1399: ^snw(2)=3
1400: ^snw(3)=""
1.1 snw 1401: @end example
1402:
1.28 snw 1403: The following code will retrieve the next subscripted name after @code{^snw(1)}:
1.1 snw 1404:
1405: @example
1.28 snw 1406: @code{SET NEXTNAM=$QUERY(^snw(1)) ; => ^snw(1,2)}
1.1 snw 1407: @end example
1408:
1409: @node $RANDOM()
1410: @section $RANDOM
1411: @cindex $RANDOM
1412: @cindex intrinsic functions, $RANDOM
1413:
1414: @emph{Syntax}
1415:
1416: @example
1417: $RANDOM(@emph{max})
1418: @end example
1419:
1420: Returns a pseudo-random integer in the range of @code{0..@emph{max} - 1}
1421:
1422: @node $REVERSE()
1423: @section $REVERSE
1424: @cindex $REVERSE
1425: @cindex intrinsic functions, $REVERSE
1426:
1427: @emph{Syntax}
1428:
1429: @example
1430: $REVERSE(@emph{s})
1431: @end example
1432:
1433: Returns the reverse of string @emph{s}.
1434:
1435: @emph{Example}
1436:
1437: @example
1438: SET FOO=$REVERSE("ABC") ; => CBA
1439: @end example
1440:
1441: @node $SELECT()
1442: @section $SELECT
1443: @cindex $SELECT
1444: @cindex intrinsic functions, $SELECT
1445:
1446: 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.
1447:
1448: @emph{Example}
1449:
1450: @example
1451: SET FOO=$SELECT(1=2:"math is broken",1=1:"the world makes sense") ; => "the world makes sense"
1452: @end example
1453:
1454: @node $STACK()
1455: @section $STACK
1456: @cindex $STACK
1457: @cindex intrinsic functions, $STACK
1458:
1459: Returns information about the program execution stack. The @code{$STACK} intrinsic function has both a one-argument form and a two-argument form.
1460:
1461: @emph{Syntax (One-Argument)}
1462:
1463: @example
1464: $STACK(@emph{<num>})
1465: @end example
1466:
1467: If @emph{num} is @code{0}, returns the command with which this FreeM instance was invoked.
1468:
1469: If @emph{num} is @code{-1}, returns the current program execution stack level.
1470:
1471: 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:
1472:
1473: @table @asis
1474:
1475: @item @code{$$}
1476: If @code{$STACK(@emph{<num>})="$$"}, program execution stack level @code{num} was created as the result of an extrinsic function call
1477:
1478: @item @emph{<m-command>}
1479: 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.
1480:
1481: @end table
1482:
1483: @emph{Syntax (Two-Argument})
1484:
1485: @example
1486: $STACK(@emph{<num>},"[ECODE|MCODE|PLACE]")
1487: @end example
1488:
1489: Returns the error codes, M program code, or entryref applicable to the action that created program execution stack level @emph{num}.
1490:
1491: @node $TEXT()
1492: @section $TEXT
1493: @cindex $TEXT
1494: @cindex intrinsic functions, $TEXT
1495:
1496: Returns a line of code from a routine.
1497:
1498: @node $TRANSLATE()
1499: @section $TRANSLATE
1500: @cindex $TRANSLATE
1501: @cindex intrinsic functions, $TRANSLATE
1502:
1.25 snw 1503: Replaces characters in a string.
1504:
1505: The first argument is a string expression representing the text to be changed.
1506:
1507: The second argument is a list of characters to replace.
1508:
1509: The third argument is a list of characters to use as the replacements for the characters in the second argument.
1510:
1511: @emph{Example}
1512:
1513: @example
1514: DEFAULT.USER> W $TRANSLATE("twig","wt","rb")
1515: brig
1516: @end example
1517:
1.1 snw 1518: @node $TYPE()
1519: @section $TYPE
1520: @cindex $TYPE
1521: @cindex intrinsic functions, $TYPE
1522: @cindex object functions, $TYPE
1523:
1524: Returns a string giving the class of the object specified in the parameter.
1525:
1526: @xref{Object-Oriented Programming}
1527:
1528: @node $VIEW()
1529: @section $VIEW
1530: @cindex $VIEW
1531: @cindex intrinsic functions, $VIEW
1532:
1533: @node $ZBOOLEAN()
1534: @section $ZBOOLEAN
1535: @cindex $ZBOOLEAN
1536: @cindex intrinsic functions, $ZBOOLEAN
1537: @cindex intrinsic functions, implementation-specific
1538:
1539:
1540: Performs @emph{boolean-operation} on numeric arguments @emph{A} and @emph{B}.
1541:
1542: @emph{Syntax}
1543:
1544: @example
1545: SET RESULT=$ZBOOLEAN(@emph{A},@emph{B},@emph{boolean-operation})
1546: @end example
1547:
1548: @code{$ZBOOLEAN} Operations (@emph{boolean-operation} values)
1549:
1550: @table @code
1551: @item 0
1552: Always @emph{false}
1553: @item 1
1554: @code{A AND B}
1555: @item 2
1556: @code{A AND NOT B}
1557: @item 3
1558: @code{A}
1559: @item 4
1560: @code{NOT A AND B}
1561: @item 5
1562: @code{B}
1563: @item 6
1564: @code{A XOR B}
1565: @item 7
1566: @code{A OR B}
1567: @item 8
1568: @code{A NOR B}
1569: @item 9
1570: @code{A EQUALS B}
1571: @item 10
1572: @code{NOT B}
1573: @item 11
1574: @code{A OR NOT B}
1575: @item 12
1576: @code{NOT A}
1577: @item 13
1578: @code{NOT A OR B}
1579: @item 14
1580: @code{A NAND B}
1581: @item 15
1582: Always @emph{true}
1583: @end table
1584:
1585: @node $ZCALL()
1586: @section $ZCALL
1587: @cindex $ZCALL
1588: @cindex intrinsic functions, $ZCALL
1589: @cindex intrinsic functions, implementation-specific
1590:
1.26 snw 1591: Purpose unknown.
1592:
1.1 snw 1593: @node $ZCRC()
1594: @section $ZCRC
1595: @cindex $ZCRC
1596: @cindex intrinsic functions, $ZCRC
1597: @cindex intrinsic functions, implementation-specific
1598:
1599: Returns a checksum of @code{arg1}.
1600:
1601: @emph{Syntax}
1602:
1603: @code{$ZCRC(@emph{arg1})}
1604:
1605: @code{SET VAR=$ZCRC("MUMPS") ; => 86}
1606:
1607: @node $ZDATA()
1608: @section $ZDATA
1609: @cindex $ZDATA
1610: @cindex intrinsic functions, $ZDATA
1611: @cindex intrinsic functions, implementation-specific
1612:
1.26 snw 1613: Purpose unknown.
1614:
1.1 snw 1615: @node $ZDATE()
1616: @section $ZDATE
1617: @cindex $ZDATE
1618: @cindex intrinsic functions, $ZDATE
1619: @cindex intrinsic functions, implementation-specific
1620:
1621: Converts a @code{@ref{$HOROLOG}} string into a human-readable date.
1622:
1623: @emph{Syntax}
1624:
1625: @example
1626: SET VAR=$ZDATE($H[,@emph{<format-string>}])
1627: @end example
1628:
1629: 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}).
1630:
1631: @xref{^$SYSTEM}
1632:
1633: @node $ZEDIT()
1634: @section $ZEDIT
1635: @cindex $ZEDIT
1636: @cindex intrinsic functions, $ZEDIT
1637: @cindex intrinsic functions, implementation-specific
1638:
1.26 snw 1639: Purpose unknown.
1640:
1.1 snw 1641: @node $ZHOROLOG()
1642: @section $ZHOROLOG
1643: @cindex $ZHOROLOG
1644: @cindex intrinsic functions, $ZHOROLOG
1645: @cindex intrinsic functions, implementation-specific
1646:
1647: Converts date and/or time values producible by @code{@ref{$ZDATE()}} or @code{@ref{$ZTIME()}} to @code{@ref{$HOROLOG}} format.
1648:
1649: @emph{Syntax}
1650:
1651: @example
1652: $ZHOROLOG(@emph{<date-value>},@emph{<format-string>})
1653: @end example
1654:
1655: @emph{<date-value>} is a date or time string compatible with the formats from @code{@ref{$ZDATE()}} or @code{@ref{$ZTIME}}.
1656:
1657: @emph{<format-string>} is a format string of the same format as used by the @code{strptime(3)} UNIX function.
1658:
1659: @node $ZKEY()
1660: @section $ZKEY
1661: @cindex $ZKEY
1662: @cindex intrinsic functions, $ZKEY
1663: @cindex intrinsic functions, implementation-specific
1664:
1.26 snw 1665: Purpose unknown.
1666:
1.1 snw 1667: @node $ZLENGTH()
1668: @section $ZLENGTH
1669: @cindex $ZLENGTH
1670: @cindex intrinsic functions, $ZLENGTH
1671: @cindex intrinsic functions, implementation-specific
1672:
1.26 snw 1673: Purpose unknown.
1674:
1.1 snw 1675: @node $ZLSD()
1676: @section $ZLSD
1677: @cindex $ZLSD
1678: @cindex intrinsic functions, $ZLSD
1679: @cindex intrinsic functions, implementation-specific
1680:
1681: 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.
1682:
1683: @emph{Syntax}
1684:
1685: @code{SET VAR=$ZLSD(@emph{arg1},@emph{arg2})}
1686:
1687: @emph{Example}
1688:
1689: @code{SET VAR=$ZLSD("KITTENS","MITTENS") ; => 1}
1690:
1691: @node $ZM()
1692: @section $ZM
1693: @cindex $ZM
1694: @cindex intrinsic functions, $ZM
1695: @cindex intrinsic functions, implementation-specific
1696:
1697: @node $ZNAME()
1698: @section $ZNAME
1699: @cindex $ZNAME
1700: @cindex intrinsic functions, $ZNAME
1701: @cindex intrinsic functions, implementation-specific
1702:
1.26 snw 1703: Purpose unknown.
1704:
1.1 snw 1705: @node $ZNEXT()
1706: @section $ZNEXT
1707: @cindex $ZNEXT
1708: @cindex intrinsic functions, $ZNEXT
1709: @cindex intrinsic functions, implementation-specific
1710:
1.26 snw 1711: Purpose unknown.
1712:
1.1 snw 1713: @node $ZORDER()
1714: @section $ZORDER
1715: @cindex $ZORDER
1716: @cindex intrinsic functions, $ZORDER
1717: @cindex intrinsic functions, implementation-specific
1718:
1.26 snw 1719: Purpose unknown.
1720:
1.1 snw 1721: @node $ZPIECE()
1722: @section $ZPIECE
1723: @cindex $ZPIECE
1724: @cindex intrinsic functions, $ZPIECE
1725: @cindex intrinsic functions, implementation-specific
1726:
1.26 snw 1727: Purpose unknown.
1728:
1.1 snw 1729: @node $ZPREVIOUS()
1730: @section $ZPREVIOUS
1731: @cindex $ZPREVIOUS
1732: @cindex intrinsic functions, $ZPREVIOUS
1733: @cindex intrinsic functions, implementation-specific
1734:
1.26 snw 1735: Purpose unknown.
1736:
1.1 snw 1737: @node $ZREPLACE()
1738: @section $ZREPLACE
1739: @cindex $ZREPLACE
1740: @cindex intrinsic functions, $ZREPLACE
1741: @cindex intrinsic functions, implementation-specific
1742:
1743: Replaces all instances of @code{arg2} with @code{arg3} in string @code{arg1}.
1744:
1745: @emph{Syntax}
1746: @code{$ZREPLACE(@emph{arg1},@emph{arg2},@emph{arg3})}
1747:
1748: @emph{Example}
1749:
1750: @code{SET VAR=$ZREPLACE("CAT","C","B") ; => BAT}
1751:
1752: @node $ZSYNTAX()
1753: @section $ZSYNTAX
1754: @cindex $ZSYNTAX
1755: @cindex intrinsic functions, $ZSYNTAX
1756: @cindex intrinsic functions, implementation-specific
1757:
1758: @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.
1759:
1760: @emph{Syntax}
1761: @example
1762: $ZSYNTAX(@emph{expr V mcode})
1763: @end example
1764:
1765: If no syntax error is found, returns the empty string.
1766:
1767: 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.
1768:
1769: @node $ZTIME()
1770: @section $ZTIME
1771: @cindex $ZTIME
1772: @cindex intrinsic functions, $ZTIME
1773: @cindex intrinsic functions, implementation-specific
1774:
1775: Converts a @code{@ref{$HOROLOG}} string into a human-readable time.
1776:
1777: @emph{Syntax}
1778:
1779: @example
1780: SET VAR=$ZTIME($H[,@emph{<format-string>}])
1781: @end example
1782:
1783: 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}).
1784:
1785: @node OBJECT Methods
1786: @chapter OBJECT Methods
1787:
1788: These methods are part of the @code{^%OBJECT} class, from which all FreeM objects ultimately inherit.
1789:
1790: 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.
1791:
1792: @menu
1793: * $$TONUMBER:: Returns the canonical numeric representation of the object.
1794: * $$TYPE:: Returns the fully-qualified class name of the object.
1795: * $$VALUE:: Returns the value of the object.
1796: @end menu
1797:
1798: @node $$TONUMBER
1799: @section $$TONUMBER
1800:
1801: Returns (when applicable) a canonical numeric representation of the referenced object.
1802:
1803: @emph{Syntax}
1804:
1805: @example
1806: W $$MYOBJECT.TONUMBER(),!
1807: @end example
1808:
1809: If no canonical numeric representation of the object is possible, will return the empty string.
1810:
1811: @node $$TYPE
1812: @section $$TYPE
1813:
1814: Returns the fully-qualified class of the referenced object.
1815:
1816: @emph{Syntax}
1817:
1818: @example
1819: W $$MYOBJECT.TYPE()
1820: @end example
1821:
1822: Note that M variables that are created by non-object-oriented means will be objects of the @code{^%STRING} class.
1823:
1824: @node $$VALUE
1825: @section $$VALUE
1826:
1827: Returns the value of the referenced object.
1828:
1829: @emph{Syntax}
1830:
1831: @example
1832: W $$MYOBJECT.VALUE()
1833: @end example
1834:
1835: @node STRING Methods
1836: @chapter STRING Methods
1837:
1838: These are methods inherent to the @code{^%STRING} class, which is the default class for M variables created without specifying a class.
1839:
1840: @menu
1841: * $$ASCII:: Return the ASCII code of a character within the string.
1842: * $$DATA:: Return tree characteristics of the string.
1843: * $$DISTANCE:: Determine Levenstein distance between this string and another.
1844: * $$EXTRACT:: Return a substring of the string.
1845: * $$FIND:: Find the position of a substring within the string.
1846: * $$FNUMBER:: Format numbers.
1847: * $$JUSTIFY:: Pad the string to specific positions.
1848: * $$LENGTH:: Return the length of the string.
1849: * $$PIECECOUNT:: Return the count of pieces existing between instances of a delimiter.
1850: * $$PIECE:: Return a delimited subset of the string.
1851: * $$REPLACE:: Replace instances of a substring within the string.
1852: * $$REVERSE:: Reverse the order of characters in the string.
1853: * $$TOLOWER:: Return a lowercase version of the string.
1854: * $$TOUPPER:: Return an uppercase version of the string.
1855: * $$TRANSLATE:: Replace individual characters within the string.
1856: @end menu
1857:
1858: @node $$ASCII
1859: @section $$ASCII
1860:
1861: Returns the ASCII code of a character within the string. See @ref{$ASCII()}.
1862:
1863: @emph{Syntax}
1864:
1865: @example
1866: W $$MYOBJECT.ASCII(3)
1867: @end example
1868:
1869: The above example returns the ASCII code in position 3 of string object @code{MYOBJECT}.
1870:
1871: @node $$DATA
1872: @section $$DATA
1873:
1874: Returns the value of the @code{$DATA} intrinsic function as performed on the value of the object. See @ref{$DATA()}.
1875:
1876: @emph{Syntax}
1877:
1878: @example
1879: W $$MYOBJECT.DATA()
1880: @end example
1881:
1882: @node $$DISTANCE
1883: @section $$DISTANCE
1884:
1885: Returns the Levenstein distance between the string and another string. See @ref{$ZLSD()}.
1886:
1887: @emph{Syntax}
1888:
1889: @example
1890: W $$MYOBJECT.DISTANCE("someString")
1891: @end example
1892:
1893: @node $$EXTRACT
1894: @section $$EXTRACT
1895:
1896: Returns a substring of the string. See @ref{$EXTRACT()}.
1897:
1898: @emph{Syntax}
1899:
1900: @example
1901: $$<objectName>.EXTRACT(<start>,<end>)
1902: @end example
1903:
1904:
1905: @node $$FIND
1906: @section $$FIND
1907:
1.25 snw 1908: Finds the character immediately following the first occurence of a substring within a string.
1909:
1910: The first argument is the substring to be located.
1911:
1912: The second argument is the position within the string at which to begin searching.
1913:
1914: See @ref{$FIND()}.
1915:
1.1 snw 1916: @node $$FNUMBER
1917: @section $$FNUMBER
1918:
1.25 snw 1919: Formats a number according to a set of formatting codes.
1920:
1921: The argument is a series of formatting codes. See @ref{$FNUMBER()} for details.
1922:
1.1 snw 1923: @node $$JUSTIFY
1924: @section $$JUSTIFY
1925:
1.25 snw 1926: Right-justifies a string based on a specified fixed length.
1927:
1928: The first argument is the character length of the output.
1929:
1930: 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.
1931:
1932: See @ref{$JUSTIFY()} for details.
1933:
1.1 snw 1934: @node $$LENGTH
1935: @section $$LENGTH
1936:
1.25 snw 1937: Returns the length of the string.
1938:
1.1 snw 1939: @node $$PIECECOUNT
1940: @section $$PIECECOUNT
1941:
1.25 snw 1942: Returns the number of items in a list delimited by the character specified in the argument.
1943:
1.1 snw 1944: @node $$PIECE
1945: @section $$PIECE
1946:
1.25 snw 1947: @emph{Syntax}
1948:
1949: @code{$PIECE(@emph{d}[,@emph{n}[,@emph{end}]])}
1950:
1951: Accesses the @code{n}th through @code{end} @code{d}-delimited pieces of the string.
1952:
1953: The first argument is the delimiter to be used.
1954:
1955: The optional second argument is the first @code{d}-delimited piece to access, and defaults to @code{1}.
1956:
1957: The optional third argument is the final @code{d}-delimited piece to access, and defaults to the value of the third argument (@code{n}).
1958:
1959:
1.1 snw 1960: @node $$REPLACE
1961: @section $$REPLACE
1962:
1.25 snw 1963: @emph{Syntax}
1964: @code{myString.$$REPLACE(@emph{arg1},@emph{arg2})}
1965:
1966: Replaces all instances of @code{arg2} with @code{arg3} in @code{myString}.
1967:
1.1 snw 1968: @node $$REVERSE
1969: @section $$REVERSE
1970:
1.25 snw 1971: Returns the reverse of the string.
1972:
1.1 snw 1973: @node $$TOLOWER
1974: @section $$TOLOWER
1975:
1.25 snw 1976: Returns an all-lowercase version of the string.
1977:
1.1 snw 1978: @node $$TOUPPER
1979: @section $$TOUPPER
1980:
1.25 snw 1981: Returns an all-uppercase version of the string.
1982:
1.1 snw 1983: @node $$TRANSLATE
1984: @section $$TRANSLATE
1985:
1.25 snw 1986: Identical to @ref{$TRANSLATE()}, except that the arguments are shifted left by one, and the input string is implicit (the object).
1987:
1.1 snw 1988: @node Commands
1989: @chapter Commands
1990: @cindex commands
1991:
1992: @menu
1993: * @@:: Execute the following expression as M code.
1994: * !:: Run an external program or command.
1995: * !!:: Launch a subshell from FreeM direct mode.
1996: * ABLOCK:: Increment the block counter for one or more event classes.
1997: * ASSERT:: Raise error when a conditional expression evaluates @emph{false}.
1998: * ASTART:: Enable asynchronous event handling for one or more event classes.
1999: * ASTOP:: Disable asynchronous event handling for one or more event classes.
2000: * AUNBLOCK:: Decrement the block counter for one or more event classes.
2001: * BREAK:: Interrupt a running routine to allow interactive debugging.
2002: * CLOSE:: Close an input/output device.
2003: * CONST:: Define a constant that cannot be altered after initial definition.
2004: * DO:: Transfer program control to one or more subroutines or introduces a new execution level.
2005: * ELSE:: Execute the remainder of a line if @code{@ref{$TEST}} evaluates @emph{false}.
2006: * FOR:: Repeat execution of a line or block of code.
2007: * GOTO:: Unconditionally transfer program execution to a supplied @emph{entryref}.
2008: * HALT:: Terminate the current FreeM interpreter instance.
2009: * HANG:: Temporarily suspend the running program.
2010: * IF:: Execute the remainder of a line if a conditional expression evaluates @emph{true}.
2011: * JOB:: Execute an @emph{entryref} in a child process.
2012: * KILL:: Remove data from a local, global, or structured system variable.
2013: * KSUBSCRIPTS:: Kill only the descendant subscripts of a local, global, global, or structured system variable.
2014: * KVALUE:: Kill only the value of a local, global, or structured system variable.
2015: * LOCK:: Control advisory locking for concurrency control.
2016: * MAP:: Map a global name to a non-default namespace.
2017: * MERGE:: Merge contents of one local, global, or structured system variable into another.
2018: * NEW:: Introduce a new scope for a specified local variable or intrinsic special variable or instantiate an object.
2019: * OPEN:: Open a sequential or socket input/output device.
2020: * QUIT:: End execution of the current process level, optionally with return value.
2021: * READ:: Read input from an input/output device.
2022: * SET:: Set the value of a local variable, global, intrinsic special variable, or structured system variable.
2023: * TCOMMIT:: Commit a transaction.
2024: * THEN:: Preserve @code{@ref{$TEST}} until the end of the current line.
2025: * THROW:: Programmatically raise an error condition.
2026: * TROLLBACK:: Roll back all pending transactions.
2027: * TSTART:: Introduce a new transaction processing level.
2028: * UNMAP:: Remove a mapping of a global to a non-default namespace.
2029: * USE:: Set the currently-active input/output device.
2030: * VIEW:: Modify FreeM internal parameters.
2031: * WATCH:: Enable or disable watchpoints, or set or clear watchpoints on specified globals, locals, or structured system variables.
2032: * WITH:: Set prefix for future variable references.
2033: * WRITE:: Write output to current input/output device.
2034: * XECUTE:: Interpret string as M code.
2035: * ZBREAK:: Unknown.
2036: * ZGO:: Unknown.
2037: * ZHALT:: Unknown.
2038: * ZINSERT:: Insert code into routine buffer.
2039: * ZJOB:: Unknown.
2040: * ZLOAD:: Load routine into routine buffer.
2041: * ZNEW:: Unknown.
2042: * ZPRINT:: Print contents of routine buffer.
2043: * ZQUIT:: Unknown.
2044: * ZREMOVE:: Remove code from routine buffer.
2045: * ZSAVE:: Save routine buffer to disk.
2046: * ZTRAP:: Unknown.
2047: * ZWRITE:: Write local variable, global, or structured system variable to @code{@ref{$IO}}.
2048: @end menu
2049:
2050: @node @@
2051: @section @@
2052: @cindex @@
2053: @cindex commands, @@
2054: @cindex commands, implementation-specific
2055: @cindex commands, non-standard
2056:
2057: Executes FreeM code @emph{expr V mcode}.
2058:
2059: @emph{Syntax}
2060:
2061: @example
2062: @@@emph{expr V mcode}
2063: @end example
2064:
2065: @emph{Example (Using Variable)}
2066:
2067: @example
1.22 snw 2068: DEFAULT.USER> SET FOO="WRITE ""HELLO WORLD"",!"
2069: DEFAULT.USER> @@FOO
1.1 snw 2070:
2071: HELLO WORLD
2072:
1.22 snw 2073: DEFAULT.USER>
1.1 snw 2074: @end example
2075:
2076: @emph{Example (Using String Literal)}
2077:
2078: @example
1.22 snw 2079: DEFAULT.USER> @@"WRITE ""HELLO WORLD"",!"
1.1 snw 2080:
2081: HELLO WORLD
2082:
1.22 snw 2083: DEFAULT.USER>
1.1 snw 2084: @end example
2085:
2086: @emph{Example (Using Indirection)}
2087:
2088: @example
1.22 snw 2089: DEFAULT.USER> SET FOO="BAR"
1.1 snw 2090:
1.22 snw 2091: DEFAULT.USER> SET BAR="WRITE ""HELLO WORLD"",!"
1.1 snw 2092:
1.22 snw 2093: DEFAULT.USER> @@@@FOO
1.1 snw 2094:
2095: HELLO WORLD
2096:
1.22 snw 2097: DEFAULT.USER>
1.1 snw 2098: @end example
2099:
2100:
2101: @node !
2102: @section !
2103: @cindex !
2104: @cindex commands, !
2105: @cindex commands, external
2106: @cindex commands, non-standard
2107: @emph{FreeM Extension}
2108:
2109: 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}.
2110:
2111: 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.
2112:
2113: 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{%}.
2114:
2115: @code{%} contains the number of lines in the input or output. @code{%(1)..%(@emph{n})} contains the data for lines 1-@emph{n}.
2116:
2117: @node !!
2118: @section !!
2119: @cindex !!
2120: @cindex commands, !!
2121: @cindex commands, external
2122: @cindex commands, non-standard
2123: @emph{FreeM Extension}
2124:
2125: Launches a subshell within the FreeM direct mode, allowing the user to run operating system commands.
2126:
2127: @example
1.22 snw 2128: DEFAULT.USER> !!
1.1 snw 2129:
2130: Type Ctrl-D to exit from the shell
2131: $ uname -a
2132: Linux hesperos 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux
2133: $ exit
2134:
1.22 snw 2135: DEFAULT.USER>
1.1 snw 2136: @end example
2137:
2138:
2139: @node ABLOCK
2140: @section ABLOCK
2141: @cindex ABLOCK
2142: @cindex commands, ABLOCK
2143:
2144: 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).
2145:
2146: 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.
2147:
2148: @emph{Syntax}
2149:
2150: @example
2151: ABLOCK@emph{:postcondition}
2152: @end example
2153:
2154: 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.
2155:
2156: @example
2157: ABLOCK@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2158: @end example
2159:
2160: 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.
2161:
2162: @example
2163: ABLOCK@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN}
2164: @end example
2165:
2166: 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.
2167:
2168: @node ASSERT
2169: @section ASSERT
2170: @cindex ASSERT
2171: @cindex commands, ASSERT
2172: @cindex commands, debugging
2173: @cindex commands, implementation-specific
2174: @cindex commands, non-standard
2175: @emph{FreeM Extension}
2176:
2177: 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.
2178:
2179: The @code{ASSERT} error is catchable whether using standard-style, FreeM-style, or DSM 2.0-style error processing.
2180:
2181: @emph{Syntax}
2182:
2183: @example
2184: ASSERT@emph{:postcondition} @emph{<tvexpr>}
2185: @end example
2186:
2187: @emph{Example}
2188:
2189: @example
1.22 snw 2190: DEFAULT.USER> SET DEBUG=1
1.1 snw 2191:
2192:
1.22 snw 2193: DEFAULT.USER> ASSERT:DEBUG 1=1
1.1 snw 2194:
2195:
1.22 snw 2196: DEFAULT.USER> ASSERT:DEBUG 1=0
1.1 snw 2197:
2198:
2199: >> Error ZASSERT: programmer assertion failed in SYSTEM::^%SYSINIT [$STACK = 0]
2200: >> ASSERT:DEBUG 1=0
2201: ^
2202: @end example
2203:
2204: @node ASTART
2205: @section ASTART
2206: @cindex ASTART
2207: @cindex commands, ASTART
2208:
2209: Enables asynchronous event handling for one or more event classes.
2210:
2211: @emph{Syntax}
2212:
2213: @example
2214: ASTART@emph{:postcondition}
2215: @end example
2216:
2217: 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.
2218:
2219: @example
2220: ASTART@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2221: @end example
2222:
2223: 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.
2224:
2225: @example
2226: ASTART@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN})
2227: @end example
2228:
2229: 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.
2230:
2231: @node ASTOP
2232: @section ASTOP
2233: @cindex ASTOP
2234: @cindex commands, ASTOP
2235:
2236: Disables asynchronous event handling for one or more event classes.
2237:
2238: @emph{Syntax}
2239:
2240: @example
2241: ASTOP@emph{:postcondition}
2242: @end example
2243:
2244: 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.
2245:
2246: @example
2247: ASTOP@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2248: @end example
2249:
2250: 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.
2251:
2252: @example
2253: ASTOP@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN})
2254: @end example
2255:
2256: 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.
2257:
2258: @node AUNBLOCK
2259: @section AUNBLOCK
2260: @cindex AUNBLOCK
2261: @cindex commands, AUNBLOCK
2262:
2263: Decrements the event block counter for one or more event classes.
2264:
2265: @emph{Syntax}
2266:
2267: @example
2268: AUNBLOCK@emph{:postcondition}
2269: @end example
2270:
2271: 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.
2272:
2273: @example
2274: AUNBLOCK@emph{:postcondition} @emph{evclass1}...,@emph{evclassN}
2275: @end example
2276:
2277: 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.
2278:
2279: @example
2280: AUNBLOCK@emph{:postcondition} (@emph{evclass1}...,@emph{evclassN}
2281: @end example
2282:
2283: 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.
2284:
2285:
2286: @node BREAK
2287: @section BREAK
2288: @cindex BREAK
2289: @cindex commands, BREAK
2290:
2291: Interrupts running routine to allow interactive debugging.
2292:
2293: @emph{Syntax}
2294:
2295: @example
2296: @code{BREAK@emph{:postcondition}}
2297: @end example
2298:
2299: In its argumentless form, @code{BREAK} suspends execution of running code, provided the optional @emph{postcondition} is @emph{true} or omitted.
2300:
2301: @example
2302: @code{BREAK@emph{:postcondition} @emph{breakflag}}
2303: @end example
2304:
2305: @emph{FreeM Extension}
2306:
1.35 snw 2307: 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 2308: The following table enumerates the possible values of @emph{breakflag}
2309:
2310: @table @code
1.35 snw 2311: @item "DEBUG"
2312: Enters the interactive debugger
1.1 snw 2313: @item 0
2314: Disables @emph{Ctrl-C} handling
2315: @item -2
2316: Enables normal FreeM error handling
2317: @item 2
2318: Enables @emph{Digital Standard MUMPS} v2 error handling
2319: @item @emph{any integer value other than 0, 2, or -2}
2320: Enables @emph{Ctrl-C} handling
2321: @end table
2322:
2323: @node CLOSE
2324: @section CLOSE
2325: @cindex CLOSE
2326: @cindex commands, CLOSE
2327:
2328: Closes an input/output device.
2329:
2330: @emph{Syntax}
2331:
2332: @example
2333: @code{CLOSE@emph{:postcondition}}
2334: @end example
2335:
2336: 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.
2337:
2338: @example
2339: @code{CLOSE@emph{:postcondition} @emph{channel}}
2340: @end example
2341:
2342: 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.
2343:
2344: @node CONST
2345: @section CONST
2346: @cindex CONST
2347: @cindex commands, CONST
2348: @cindex commands, non-standard
2349: @emph{FreeM Extension}
2350:
2351: 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.
2352:
2353: Constants must only be locals, and globals are not supported.
2354:
2355: @emph{Syntax}
2356:
2357: @example
2358: @code{CONST@emph{:postcondition} @emph{mref1}=@emph{initial-value1},...,@emph{mrefN}=@emph{initial-valueN}}
2359: @end example
2360:
2361: @node DO
2362: @section DO
2363: @cindex DO
2364: @cindex commands, DO
2365:
2366: 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.
2367:
2368: @emph{Syntax}
2369:
2370: @example
2371: DO[@emph{:postcondition}] @emph{entryref}[@emph{:postcondition}[,...]]
2372: @end example
2373:
1.35 snw 2374: @cartouche
2375: @quotation
2376: @emph{Non-Standard Behavior}
2377:
2378: 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.
2379: @end quotation
2380: @end cartouche
2381:
1.1 snw 2382: 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.
2383:
2384: @emph{Syntax}
2385:
2386: @example
2387: DO[@emph{:postcondition}]
2388: @end example
2389:
2390: @node ELSE
2391: @section ELSE
2392: @cindex ELSE
2393: @cindex commands, ELSE
2394:
2395: 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.
2396:
2397: @emph{Syntax}
2398:
2399: @example
2400: ELSE[@emph{:postcondition}]
2401: @end example
2402:
2403: @cartouche
2404: @quotation
2405: @emph{Non-Standard Behavior}
2406:
2407: FreeM allows a @emph{postcondition} on @code{ELSE}. While explicitly forbidden in the @emph{standard}--and for good reason--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.
2408:
1.35 snw 2409: 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 2410: @end quotation
2411: @end cartouche
2412:
2413: @node FOR
2414: @section FOR
2415: @cindex FOR
2416: @cindex commands, FOR
2417:
2418: 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.
2419:
2420: @emph{Syntax}
2421:
2422: @example
2423: FOR[@emph{:postcondition}]
2424: @end example
2425:
2426: @cartouche
2427: @quotation
2428: @emph{Non-Standard Behavior}
2429:
2430: 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.
2431:
2432: 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.
2433: @end quotation
2434: @end cartouche
2435:
2436: 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.
2437:
2438: 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}.
2439:
2440: @emph{Syntax}
2441:
2442: @example
2443: FOR[@emph{:postcondition}] @emph{glvn}=@emph{initializer-expression}:@emph{increment-expression}:@emph{max-expression}
2444: @end example
2445:
2446: @emph{Example}
2447:
2448: @example
1.22 snw 2449: DEFAULT.USER> FOR I=1:1:10 WRITE I,!
1.1 snw 2450:
2451: 1
2452: 2
2453: 3
2454: 4
2455: 5
2456: 6
2457: 7
2458: 8
2459: 9
2460: 10
2461:
1.22 snw 2462: DEFAULT.USER> FOR I=2:2:10 WRITE I,!
1.1 snw 2463:
2464: 2
2465: 4
2466: 6
2467: 8
2468: 10
2469: @end example
2470:
2471: 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.
2472:
2473: @emph{Syntax}
2474:
2475: @example
2476: FOR[@emph{:postcondition}] @emph{glvn}=@emph{expr1}[,..@emph{exprN}]
2477: @end example
2478:
2479: @emph{Example}
2480:
2481: @example
1.22 snw 2482: DEFAULT.USER> FOR I=60,"FOO",-3,"George",1450,$HOROLOG WRITE I,!
1.1 snw 2483:
2484: 60
2485: FOO
2486: -3
2487: George
2488: 1450
2489: 66106,52388
2490: @end example
2491:
2492: @node GOTO
2493: @section GOTO
2494: @cindex GOTO
2495: @cindex commands, GOTO
2496:
2497: 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}.
2498:
2499: @emph{Syntax}
2500:
2501: @example
2502: GOTO[@emph{:postcondition}] @emph{entryref}
2503: @end example
2504:
1.35 snw 2505: @cartouche
2506: @quotation
2507: @emph{Non-Standard Behavior}
2508:
2509: 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.
2510: @end quotation
2511: @end cartouche
2512:
2513:
1.1 snw 2514: @node HALT
2515: @section HALT
2516: @cindex HALT
2517: @cindex commands, HALT
2518:
2519: Halts program execution and frees resources allocated during execution, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2520:
2521: @emph{Syntax}
2522:
2523: @example
2524: HALT[@emph{:postcondition}]
2525: @end example
2526:
2527: @node HANG
2528: @section HANG
2529: @cindex HANG
2530: @cindex commands, HANG
2531:
2532: 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.
2533:
2534: @emph{Syntax}
2535:
2536: @example
2537: HANG[@emph{:postcondition}] @emph{expr}
2538: @end example
2539:
2540: @cartouche
2541: @quotation
2542: @emph{Non-Standard Behavior}
2543:
2544: FreeM supports sub-second values for @emph{expr}.
2545: @end quotation
2546: @end cartouche
2547:
2548: @node IF
2549: @section IF
2550: @cindex IF
2551: @cindex commands, IF
2552:
2553: 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.
2554:
2555: @emph{Syntax}
2556: @example
2557: IF[@emph{:postcondition}] @emph{tvexpr}[,...@emph{tvexpr}]
2558: @end example
2559:
2560: 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.
2561:
2562: @emph{Syntax}
2563: @example
2564: IF[@emph{:postcondition}]
2565: @end example
2566:
2567: @node JOB
2568: @section JOB
2569: @cindex JOB
2570: @cindex commands, JOB
2571:
2572: Executes @emph{entryref} in a separate process, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2573:
2574: @emph{Syntax}
2575: @example
2576: JOB[@emph{:postcondition}] @emph{entryref}[:@emph{job-parameters}[:@emph{timeout}]]
2577: @end example
2578:
2579: If @emph{timeout} is supplied, FreeM will set @code{$TEST} to @emph{1} if the child process completes within @emph{timeout} seconds.
2580:
2581: @node KILL
2582: @section KILL
2583: @cindex KILL
2584: @cindex commands, KILL
2585:
2586: 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.
2587:
2588: @emph{Syntax}
2589: @example
2590: KILL[@emph{:postcondition}] @emph{glvn}[,...@emph{glvn}]
2591: @end example
2592:
2593: 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.
2594:
2595: @emph{Syntax}
2596: @example
2597: KILL[@emph{:postcondition}] (@emph{lvn}[,...@emph{lvn}])
2598: @end example
2599:
2600: In its argumentless form, @code{KILL} deletes all local variables, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2601:
2602: @emph{Syntax}
2603: @example
2604: KILL[@emph{:postcondition}]
2605: @end example
2606:
2607: @node KSUBSCRIPTS
2608: @section KSUBSCRIPTS
2609: @cindex KSUBSCRIPTS
2610: @cindex commands, KSUBSCRIPTS
2611:
2612: Kills only the descendant subscripts (but not the data value) of a referenced global, local, or SSVN (where allowed).
2613:
2614: @emph{Syntax}
2615:
2616: @example
2617: KSUBSCRIPTS@emph{:postcondition} @emph{var1},...
2618: @end example
2619:
2620: 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.
2621:
2622: @cartouche
2623: @quotation
2624: @emph{Note}
1.32 snw 2625: 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 2626: @end quotation
2627: @end cartouche
2628:
2629: @example
2630: KSUBSCRIPTS@emph{:postcondition}
2631: @end example
2632:
2633: 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.
2634:
2635: @example
2636: KSUBSCRIPTS@emph{:postcondition} (@emph{var1},...)
2637: @end example
2638:
2639: 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.
2640:
2641:
2642: @node KVALUE
2643: @section KVALUE
2644: @cindex KVALUE
2645: @cindex commands, KVALUE
2646:
2647: Kills only the data value (but not descendant subscripts) of a referenced global, local, or SSVN (where allowed).
2648:
2649: @emph{Syntax}
2650:
2651: @example
2652: KVALUE@emph{:postcondition} @emph{var1},...
2653: @end example
2654:
2655: 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.
2656:
2657: @cartouche
2658: @quotation
2659: @emph{Note}
1.32 snw 2660: 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 2661: @end quotation
2662: @end cartouche
2663:
2664: @example
2665: KVALUE@emph{:postcondition}
2666: @end example
2667:
2668: 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.
2669:
2670: @example
2671: KVALUE@emph{:postcondition} (@emph{var1},...)
2672: @end example
2673:
2674: 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.
2675:
2676: @node LOCK
2677: @section LOCK
2678: @cindex LOCK
2679: @cindex commands, LOCK
2680:
2681: Acquires or releases ownership of names.
2682:
2683: 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.
2684:
2685: @emph{Syntax}
2686: @example
2687: LOCK[@emph{:postcondition}]
2688: @end example
2689:
2690: 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}.
2691:
2692: If @code{LOCK} succeeds within @emph{timeout}, @code{$TEST} is set to @emph{1}. Otherwise, @code{$TEST} is set to @emph{0}.
2693:
2694: @emph{Syntax}
2695: @example
2696: LOCK[@emph{:postcondition}] [+|-]@emph{name}[:@emph{timeout}][,...[+|-]@emph{name}[:@emph{timeout}]]
2697: @end example
2698:
2699: @emph{Example}
2700:
1.26 snw 2701: This example will increment the lock counter for @code{^SNW} and decrement the lock counter for @code{^MJR}.
1.1 snw 2702:
2703: @example
1.26 snw 2704: LOCK +^SNW,-^MJR
1.1 snw 2705: @end example
2706:
2707: 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.
2708:
2709: If @code{LOCK} succeeds within @emph{timeout}, @code{$TEST} is set to @emph{1}. Otherwise, @code{$TEST} is set to @emph{0}.
2710:
2711: @emph{Syntax}
2712: @example
2713: LOCK[@emph{:postcondition}] @emph{name}[:@emph{timeout}][,...@emph{name}[:@emph{timeout}]]
2714: @end example
2715:
2716: @node MAP
2717: @section MAP
2718: @cindex MAP
2719: @cindex commands, MAP
2720: @cindex commands, implementation-specific
2721: @cindex commands, non-standard
2722:
2723: 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.
2724:
2725: @emph{Syntax}
2726:
2727: @example
2728: MAP[@emph{:postcondition}] GLOBAL @emph{gvn}=@emph{expr V namespace}
2729: @end example
2730:
2731: @node MERGE
2732: @section MERGE
2733: @cindex MERGE
2734: @cindex commands, MERGE
2735:
2736: Merges the contents of one global, local, or SSVN subtree to another global, local, or SSVN.
2737:
2738: @emph{Syntax}
2739:
2740: @example
2741: @code{MERGE A=^$JOB}
2742: @end example
2743:
2744: 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.
2745:
2746: @node NEW
2747: @section NEW
2748: @cindex NEW
2749: @cindex commands, NEW
2750:
2751: In all forms of @code{NEW}, @emph{name} must be a local variable name or @code{NEW}-able structured or intrinsic system variable.
2752:
2753: 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.
2754:
2755: @emph{Syntax}
2756:
2757: @example
2758: NEW[@emph{:postcondition}] @emph{name}[,...@emph{name}]
2759: @end example
2760:
2761: 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.
2762:
2763: @emph{Syntax}
2764: @example
2765: NEW[@emph{:postcondition}] (@emph{name}[,...@emph{name}])
2766: @end example
2767:
2768: 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.
2769:
2770: @emph{Syntax}
2771: @example
2772: NEW@emph{:postcondition} @emph{name}=@emph{expr}
2773: @end example
2774:
2775: 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.
2776:
1.26 snw 2777: @emph{Syntax}
2778: @example
2779: NEW@emph{:postcondition} @emph{name}=$%@emph{^CLASS}(@emph{initializer-list})
2780: @end example
2781:
2782: 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).
2783:
1.1 snw 2784: @node OPEN
2785: @section OPEN
2786: @cindex OPEN
2787: @cindex commands, OPEN
2788:
2789: Opens sequential or socket I/O devices and files and associates them with a numeric FreeM input/output channel.
2790:
2791: @emph{Syntax (Sequential Files)}
2792:
2793: @example
2794: @code{OPEN@emph{:postcondition} @emph{channel}:"@emph{filename}/@emph{access-mode}"}
2795: @end example
2796:
2797: 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.
2798: The below table lists the valid options for @emph{access-mode}:
2799:
2800: @table @code
2801: @item r
2802: Read-only access
2803: @item w
2804: Create a new file for write access
2805: @item a
2806: Write access; append to existing file
2807: @item r+
2808: Read/write access
2809: @end table
2810:
2811: @cartouche
2812: @quotation
2813: @emph{I/O Path}
2814:
2815: 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
2816: access files in other directories, you must first set the @emph{I/O Path} in @code{^$JOB($JOB,"IOPATH")}.
2817:
2818: The following example will set the I/O path to @code{/etc}:
2819:
2820: @example
2821: @code{SET ^$JOB($JOB,"IOPATH")="/etc"}
2822: @end example
2823:
2824: @end quotation
2825: @end cartouche
2826:
2827: 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}.
2828:
2829: @emph{Syntax (Network Sockets)}
2830:
2831: 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.
2832:
2833: @example
2834: OPEN@emph{:postcondition} @emph{socket-channel}:"@emph{hostname-or-address}:@emph{port}:@emph{address-family}:@emph{connection-type}"
2835: @end example
2836:
2837: @emph{Socket Parameters}
2838:
2839: @table @emph
2840:
2841: @item socket-channel
2842: The socket I/O channel to use. This must be in the range of 100-255.
2843:
2844: @item hostname-or-address
2845: 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.
2846:
2847: @item port
2848: The TCP or UDP port to which the socket will connect on the remote host.
2849:
2850: @item address-family
2851: The address family to use. Either @emph{IPV4} or @emph{IPV6}.
2852:
2853: @item connection-type
2854: Which connection type to use. Either @emph{TCP} or @emph{UDP}.
2855:
2856: @end table
2857:
2858: If you do not specify the address family and connection type, they will default to @emph{IPV4} and @emph{TCP}, respectively.
2859:
2860: @node QUIT
2861: @section QUIT
2862: @cindex QUIT
2863: @cindex commands, QUIT
2864:
2865: @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.
2866:
2867: @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}.
2868:
2869: Argumentless @code{QUIT} may also be used to exit a @code{FOR} loop occurring on the same line.
2870:
2871: @emph{Syntax}
2872: @example
2873: QUIT[@emph{:postcondition}] [@emph{expr}]
2874: @end example
2875:
2876: @node READ
2877: @section READ
2878: @cindex READ
2879: @cindex commands, READ
2880:
2881: 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.
2882:
2883: @emph{Syntax}
2884: @example
2885: READ[@emph{:postcondition}] @emph{read-argument}[,...@emph{read-argument}]
2886: @end example
2887:
2888: Each @emph{read-argument} may be one of the following:
2889:
2890: @table @asis
2891:
2892: @item String Literal
2893: String literal @emph{read-argument}s will be output to @code{$IO} unmodified.
2894:
2895: @item Format Specifier
2896: One or more of the following:
2897:
2898: @table @asis
2899: @item @code{!} (newline)
2900: Advances the cursor down by one line and returns it to the first column.
2901:
2902: @item @code{#} (form-feed)
2903: Advances the screen down by @code{$ZROWS} and moves the cursor to the upper-left corner of the screen.
2904:
2905: @item @code{?@emph{n}} (position)
2906: Advances the cursor and @code{$X} forward to position @emph{n}.
2907:
2908: @end table
2909:
2910: @item Single-Character Read (@code{*@emph{variable-name}[@emph{:timeout}]})
2911: 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}.
2912:
2913: @item Variable-Length Character Read (@code{@emph{variable-name}[@emph{:timeout}]})
2914: 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}.
2915:
2916: @item Fixed-Length Character Read (@code{@emph{variable-name}#@emph{count}[@emph{:timeout}]})
2917: 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}.
2918:
2919: @item Control Mnemonic (@code{/@emph{control-mnemonic}[@emph{(arg1[,...argN])}]})
2920: Outputs X3.64 control mnemonic @emph{control-mnemonic} to @code{$IO}. Please see the appendix on X3.64 Control Mnemonics for more information.
2921:
2922: @end table
2923:
2924: @node SET
2925: @section SET
2926: @cindex SET
2927: @cindex commands, SET
2928:
2929: The @code{SET} command places values into one or more variables, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2930:
2931: @emph{Syntax}
2932: @example
2933: SET[@emph{:postcondition}] @emph{set-argument}[=@emph{expression} | @emph{postfix-operator}][@emph{,...set-argument}[=@emph{expression} | @emph{postfix-operator}]]
2934: @end example
2935:
2936: Each @emph{set-argument} can be:
2937:
2938: @table @asis
2939: @item @emph{variable-name}
2940: A local variable, global variable, writable intrinsic special variable, or writable structured system variable.
2941:
2942: @item @emph{lhs-function}
2943: @code{$EXTRACT} or @code{$PIECE}.
2944: @end table
2945:
2946: 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}.
2947:
2948: 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.
2949:
2950: @emph{Example (postfix-operator)}
2951:
2952: @example
2953: SET A++,B-- ; increments A, decrements B
2954: @end example
2955:
2956: @node TCOMMIT
2957: @section TCOMMIT
2958: @cindex TCOMMIT
2959: @cindex commands, TCOMMIT
2960:
2961: Commits all pending transactions to the data files, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
2962:
2963: @emph{Syntax}
2964: @example
2965: TCOMMIT[@emph{:postcondition}]
2966: @end example
2967:
2968: @node THEN
2969: @section THEN
2970: @cindex THEN
2971: @cindex commands, THEN
2972:
2973: 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}.
2974:
2975: @emph{Example}
2976: @example
2977: IF 1 THEN WRITE "HELLO!",!
2978: @end example
2979:
2980: @node THROW
2981: @section THROW
2982: @cindex THROW
2983: @cindex commands, THROW
2984: @cindex commands, non-standard
2985: @emph{FreeM Extension}
2986:
2987: Raises an error condition as long as the optional @emph{postcondition} is @emph{true} or omitted.
2988:
2989: @emph{Syntax}
2990:
2991: @example
2992: @code{THROW@emph{:postcondition} @emph{expr V error-code}}
2993: @end example
2994:
2995: @emph{Example}
2996:
2997: @example
2998: @code{THROW "M102"}
2999: @end example
3000:
3001: @node TROLLBACK
3002: @section TROLLBACK
3003: @cindex TROLLBACK
3004: @cindex commands, TROLLBACK
3005:
3006: Rolls back all pending transactions for the current process, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
3007:
3008: @emph{Syntax}
3009:
3010: @example
3011: TROLLBACK[@emph{:postcondition}]
3012: @end example
3013:
3014: @node TSTART
3015: @section TSTART
3016: @cindex TSTART
3017: @cindex commands, TSTART
3018:
3019: 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.
3020:
3021: If a transaction is restartable, variables in the @emph{variables-list} will be restored to their original values on a restart of the transaction.
3022:
3023: @emph{Syntax}
3024:
3025: @example
3026: TSTART[@emph{:postcondition}] @emph{<variables-list>}:@emph{<transaction-parameters>}
3027: @end example
3028:
3029: @emph{<variables-list>} can be:
3030:
3031: @table @asis
3032:
3033: @item @code{()}
3034: Do not save off any local variables. Makes the transaction non-restartable.
3035:
3036: @item @code{*}
3037: Save off all local variables. Makes the transaction restartable.
3038:
3039: @item @code{@emph{variableName}}
3040: Saves off only one local variable, @emph{variableName}. Makes the transaction restartable.
3041:
3042: @item @code{(@emph{variableName1},...,@emph{variableNameN})}
3043: Saves off all local variables listed. Makes the transaction restartable.
3044:
3045: @end table
3046:
3047: @emph{<transaction-parameters>} can be:
3048:
3049: @table @asis
3050:
3051: @item @code{S[ERIAL]}
3052: 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.
3053:
3054: @item @code{T[RANSACTIONID]=@emph{transaction-id}}
3055: Sets the ID of the transaction to @emph{transaction-id}
3056:
3057: @end table
3058:
3059: If you are using more than one transaction parameter, surround all of them in parentheses and separate them with commas, e.g.:
3060:
3061: @example
3062: TSTART (FOO,BAR):(SERIAL,TRANSACTIONID="FOO")
3063: @end example
3064:
3065: @node UNMAP
3066: @section UNMAP
3067: @cindex UNMAP
3068: @cindex commands, UNMAP
3069: @cindex commands, implementation-specific
3070: @cindex commands, non-standard
3071:
3072: Removes any mapping connecting @emph{gvn} to a non-default namespace, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
3073:
3074: @emph{Syntax}
3075:
3076: @example
3077: UNMAP GLOBAL @emph{gvn}
3078: @end example
3079:
3080: @node USE
3081: @section USE
3082: @cindex USE
3083: @cindex commands, USE
3084:
3085: 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.
3086:
3087: @emph{Syntax (Terminal)}
3088:
3089: @example
3090: 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})]
3091: @end example
3092:
3093: For terminals, @emph{io-channel} must be 0.
3094:
3095: Semantic and functional description of each device parameter TBA.
3096:
3097: @emph{Syntax (Sequential Files)}
3098:
3099: @example
3100: USE@emph{:postcondition} @emph{io-channel}[:@emph{seek-position}:@emph{terminator}:@emph{nodelay})]
3101: @end example
3102:
3103: For sequential files, @emph{io-channel} must be in the range 1-99.
3104:
3105: Semantic and functional description of each device parameter TBA.
3106:
3107: @emph{Syntax (Network Sockets)}
3108:
3109: @example
3110: USE@emph{:postcondition} @emph{io-channel}
3111: @end example
3112:
3113: 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.
3114:
3115: @example
3116: USE@emph{:postcondition} @emph{io-channel}:/CONNECT
3117: @end example
3118:
3119: 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).
3120:
3121: For network sockets, @emph{io-channel} must be in the range 100-255.
3122:
3123: @node VIEW
3124: @section VIEW
3125: @cindex VIEW
3126: @cindex commands, VIEW
3127:
3128: Provides write access to various FreeM internal parameters, provided the optional @emph{postcondition} evaluates to @emph{true} or is omitted.
3129:
3130: @emph{Syntax}
3131: @example
3132: VIEW[@emph{:postcondition}] @emph{view-number}[:@emph{view-argument}[:@emph{view-argument}...]]
3133: @end example
3134:
3135: The @emph{view-number} argument can be one of the following:
3136:
3137: @table @asis
3138:
3139: @item @code{21} - Close All Globals
3140: Closes all global data files open in the current process. Takes no arguments.
3141:
3142: @emph{Syntax}
3143: @example
3144: VIEW 21
3145: @end example
3146:
3147: @item @code{52} - Set G0 Input Translation Table for @code{$IO}
3148:
3149: @emph{Syntax}
3150: @example
3151: VIEW 52:@emph{expr V trantab}
3152: @end example
3153:
3154: @item @code{53} - Set G0 Output Translation Table for @code{$IO}
3155:
3156: @emph{Syntax}
3157: @example
3158: VIEW 53:@emph{expr V trantab}
3159: @end example
3160:
3161: @item @code{54} - Set G1 Input Translation Table for @code{$IO}
3162:
3163: @emph{Syntax}
3164: @example
3165: VIEW 54:@emph{expr V trantab}
3166: @end example
3167:
3168: @item @code{55} - Set G1 Output Translation Table for @code{$IO}
3169:
3170: @emph{Syntax}
3171: @example
3172: VIEW 55:@emph{expr V trantab}
3173: @end example
3174:
3175: @item @code{62} - Set @code{$RANDOM} Seed Number
3176: Sets the seed number used by @code{$RANDOM} to @emph{numexpr}.
3177:
3178: @emph{Syntax}
3179: @example
3180: VIEW 62:@emph{numexpr}
3181: @end example
3182:
3183: @item @code{63} - Set @code{$RANDOM} Parameter A
3184: Sets the number used for @code{$RANDOM} Parameter A to @emph{numexpr}.
3185:
3186: @emph{Syntax}
3187: @example
3188: VIEW 63:@emph{numexpr}
3189: @end example
3190:
3191: @item @code{64} - Set @code{$RANDOM} Parameter B
3192: Sets the number used for @code{$RANDOM} Parameter B to @emph{numexpr}.
3193:
3194: @emph{Syntax}
3195: @example
3196: VIEW 64:@emph{numexpr}
3197: @end example
3198:
3199: @item @code{65} - Set @code{$RANDOM} Parameter C
3200: Sets the number used for @code{$RANDOM} Parameter C to @emph{numexpr}.
3201:
3202: @emph{Syntax}
3203: @example
3204: VIEW 65:@emph{numexpr}
3205: @end example
3206:
3207: @item @code{66} - Set or Clear @code{SIGTERM} Handling Flag
3208: 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.
3209:
3210: @emph{Syntax}
3211: @example
3212: VIEW 66:@emph{tvexpr}
3213: @end example
3214:
3215: @item @code{67} - Set or Clear @code{SIGHUP} Handling Flag
3216: 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.
3217:
3218: @emph{Syntax}
3219: @example
3220: VIEW 67:@emph{tvexpr}
3221: @end example
3222:
3223: @item @code{70} - Set @code{$ZSORT}/@code{$ZSYNTAX} Flag
3224: Selects whether @code{$ZS} resolves to @code{$ZSORT} or @code{$ZSYNTAX}.
3225:
3226: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZSYNTAX}. Otherwise, selects @code{$ZSORT}.
3227:
3228: @emph{Syntax}
3229: @example
3230: VIEW 70:@emph{tvexpr}
3231: @end example
3232:
3233: @item @code{71} - Set @code{$ZNEXT}/@code{$ZNAME} Flag
3234: Selects whether @code{$ZN} resolves to @code{$ZNEXT} or @code{$ZNAME}.
3235:
3236: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZNAME}. Otherwise, selects @code{$ZNEXT}.
3237:
3238: @emph{Syntax}
3239: @example
3240: VIEW 71:@emph{tvexpr}
3241: @end example
3242:
3243: @item @code{72} - Set @code{$ZPREVIOUS}/@code{$ZPIECE} Flag
3244: Selects whether @code{$ZP} resolves to @code{$ZPREVIOUS} or @code{$ZPIECE}.
3245:
3246: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZPIECE}. Otherwise, selects @code{$ZPREVIOUS}.
3247:
3248: @emph{Syntax}
3249: @example
3250: VIEW 72:@emph{tvexpr}
3251: @end example
3252:
3253: @item @code{73} - Set @code{$ZDATA}/@code{$ZDATE} Flag
3254: Selects whether @code{$ZD} resolves to @code{$ZDATA} or @code{$ZDATE}.
3255:
3256: If @emph{tvexpr} evaluates to @emph{true}, selects @code{$ZDATE}. Otherwise, selects @code{$ZDATA}.
3257:
3258: @emph{Syntax}
3259: @example
3260: VIEW 73:@emph{tvexpr}
3261: @end example
3262:
3263: @item @code{79} - Set Old @code{ZJOB} vs. New @code{ZJOB} Flag
3264: If @emph{tvexpr} evaluates to @emph{true}, sets the @code{ZJOB} mode to new, otherwise, sets it to old.
3265:
3266: @emph{Syntax}
3267: @example
3268: VIEW 79:@emph{tvexpr}
3269: @end example
3270:
3271: @item @code{80} - Set or Clear 8-Bit Flag
3272: If @emph{tvexpr} evaluates to @emph{true}, sets FreeM to 8-bit mode. Otherwise, sets FreeM to 7-bit mode.
3273:
3274: @emph{Syntax}
3275: @example
3276: VIEW 80:@emph{tvexpr}
3277: @end example
3278:
3279: @item @code{81} - Set or Clear PF1 Flag
3280: If @emph{tvexpr} evaluates to @emph{true}, sets the @code{PF1} flag. We do not yet know what this does.
3281:
3282: @emph{Syntax}
3283: @example
3284: VIEW 81:@emph{tvexpr}
3285: @end example
3286:
3287: @item @code{83} - Set or Clear Text in @code{$ZERROR} Flag
3288: 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}.
3289:
3290: @emph{Syntax}
3291: @example
3292: VIEW 83:@emph{tvexpr}
3293: @end example
3294:
3295: @item @code{92} - Set Type Mismatch Error Flag on @code{EUR2DEM}
3296: 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.
3297:
3298: @emph{Syntax}
3299: @example
3300: VIEW 92:@emph{tvexpr}
3301: @end example
3302:
3303: @item @code{93} - Define @code{ZKEY} Production Rule
3304: We do not know what this does.
3305:
3306: @item @code{96} - Set Global Prefix
3307: Forces global data filenames to be prefixed with the result of @emph{expr}.
3308:
3309: @emph{Syntax}
3310: @example
3311: VIEW 96:@emph{expr V string}
3312: @end example
3313:
3314: @item @code{97} - Set Global Postfix
3315: Forces global data filenames to be postfixed with the result of @emph{expr}.
3316:
3317: @emph{Syntax}
3318: @example
3319: VIEW 97:@emph{expr V string}
3320: @end example
3321:
3322: @item @code{98} - Set Routine Extension
3323: Sets the default extension for M routine filenames to the result of @emph{expr}.
3324:
3325: @emph{Syntax}
3326: @example
3327: VIEW 98:@emph{expr V string}
3328: @end example
3329:
3330: @item @code{101} - Set @code{ierr}
3331: Sets the FreeM internal @code{ierr} value to @emph{intexpr}. Used by some FreeM polyfills (commands or functions implemented in M code).
3332:
3333: @emph{Syntax}
3334: @example
3335: VIEW 101:@emph{intexpr}
3336: @end example
3337:
3338: @item @code{102} - Set @code{ierr} (Deferred)
3339: 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.
3340:
3341: @emph{Syntax}
3342: @example
3343: VIEW 102:@emph{intexpr}
3344: @end example
3345:
3346: @item @code{103} - Signal @code{MERGE} to @code{^$WINDOW} Complete
3347: Signals FreeM's MWAPI implementation that a @code{MERGE} to @code{^$WINDOW} or descendant subscripts thereof has completed.
3348:
3349: @emph{Syntax}
3350: @example
3351: VIEW 103[@emph{:subscript}]
3352: @end example
3353:
3354: @item @code{110} - Set Local @code{$ORDER}/@code{$QUERY} Data Value
3355: Sets the local variable @code{$ORDER}/@code{$QUERY} data value to the result of @emph{expr}. We're not entirely sure what this is.
3356:
3357: @emph{Syntax}
3358: @example
3359: VIEW 110:@emph{expr}
3360: @end example
3361:
3362: @item @code{111} - Set Global @code{$ORDER}/@code{$QUERY} Data Value
3363: Sets the global variable @code{$ORDER}/@code{$QUERY} data value to the result of @emph{expr}. We're not entirely sure what this is.
3364:
3365: @emph{Syntax}
3366: @example
3367: VIEW 111:@emph{expr}
3368: @end example
3369:
3370: @item @code{113} - Set @code{termio} Information
3371: We don't know what this does.
3372:
3373: @item @code{133} - Remember @code{ZLOAD} Directory on @code{ZSAVE}
3374: We don't know what this does, but it takes a @emph{tvexpr}.
3375:
3376: @emph{Syntax}
3377: @example
3378: VIEW 133:@emph{tvexpr}
3379: @end example
3380:
3381: @end table
3382:
3383: @node WATCH
3384: @section WATCH
3385: @cindex WATCH
3386: @cindex commands, WATCH
3387: @cindex commands, debugging
3388: @cindex commands, implementation-specific
3389: @cindex commands, non-standard
3390: @emph{FreeM Extension}
3391:
3392: Sets a watchpoint on a global, local, or SSVN node.
3393:
3394: @emph{Syntax}
3395:
3396:
3397: In its @emph{argumentless} form, @code{WATCH} toggles watchpoints on and off, provided the optional @emph{postcondition} is @emph{true} or omitted.
3398:
3399: @example
3400: WATCH[@emph{:postcondition}]
3401: @end example
3402:
3403: In its @emph{inclusive} form, @code{WATCH} adds, removes, or examines watchpoints, provided the optional @emph{postcondition} is @emph{true} or omitted.
3404:
3405: A @code{+} adds a new watchpoint to the following variable.
3406:
3407: A @code{-} removes an existing watchpoint for the following variable.
3408:
3409: A @code{?} examines the status of a watchpoint for the following variable.
3410:
3411: @example
3412: WATCH[@emph{:postcondition}] [+|-|?]@emph{var1}...,[+|-|?]@emph{varN}
3413: @end example
3414:
3415:
1.28 snw 3416: 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)}.
1.1 snw 3417:
3418: @example
1.22 snw 3419: DEFAULT.USER> WATCH
1.1 snw 3420:
3421: Watchpoints enabled.
3422:
1.28 snw 3423: DEFAULT.USER> WATCH +^SNW(1)
1.1 snw 3424:
1.28 snw 3425: Added '^SNW("1")' to the watchlist.
1.1 snw 3426:
1.28 snw 3427: DEFAULT.USER> SET ^SNW(1)="new value"
1.1 snw 3428:
1.28 snw 3429: >> WATCHPOINT: ^SNW("1") => 'new value' (changed 1 times)
1.1 snw 3430:
3431: @end example
3432:
3433: The following example will remove that watchpoint:
3434:
3435: @example
1.28 snw 3436: DEFAULT.USER> WATCH -^SNW(1)
1.1 snw 3437:
1.28 snw 3438: Removed '^SNW("1")' from the watchlist.
1.1 snw 3439:
1.28 snw 3440: DEFAULT.USER> WATCH ?^SNW(1)
1.1 snw 3441:
1.28 snw 3442: '^SNW("1")' is not being watched.
1.1 snw 3443: @end example
3444:
3445: @node WITH
3446: @section WITH
3447: @cindex WITH
3448: @cindex commands, WITH
3449: @cindex commands, non-standard
3450: @emph{FreeM Extension}
3451:
1.26 snw 3452: NOTE: This command may be deprecated and removed in future FreeM releases.
3453:
1.1 snw 3454: Sets a prefix to be applied to all subsequent local variable or constant references.
3455:
3456: @emph{Syntax}
3457:
3458: @example
3459: @code{WITH@emph{:postcondition} @emph{var-prefix}}
3460: @end example
3461:
3462: 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.
3463:
3464: The @emph{var-prefix} argument may be a string literal or any valid FreeM expression.
3465:
3466: @example
3467: @code{WITH@emph{:postcondition}}
3468: @end example
3469:
3470: In the above argumentless form, clears the @code{$WITH} prefix, provided the optional @emph{postcondition} is either @emph{true} or omitted. Equivalent to @code{WITH ""}.
3471:
3472:
3473: @node WRITE
3474: @section WRITE
3475: @cindex WRITE
3476: @cindex commands, WRITE
3477:
3478: @node XECUTE
3479: @section XECUTE
3480: @cindex XECUTE
3481: @cindex commands, XECUTE
3482:
3483: @node ZBREAK
3484: @section ZBREAK
3485: @cindex ZBREAK
3486: @cindex commands, ZBREAK
3487: @cindex commands, debugging
3488: @cindex commands, implementation-specific
3489: @cindex commands, non-standard
3490: @emph{FreeM Extension}
3491:
3492: @node ZGO
3493: @section ZGO
3494: @cindex ZGO
3495: @cindex commands, ZGO
3496: @cindex commands, implementation-specific
3497: @cindex commands, non-standard
3498: @emph{FreeM Extension}
3499:
3500: @node ZHALT
3501: @section ZHALT
3502: @cindex ZHALT
3503: @cindex commands, ZHALT
3504: @cindex commands, implementation-specific
3505: @cindex commands, non-standard
3506: @emph{FreeM Extension}
3507:
3508: @node ZINSERT
3509: @section ZINSERT
3510: @cindex ZINSERT
3511: @cindex commands, ZINSERT
3512: @cindex commands, implementation-specific
3513: @cindex commands, non-standard
3514: @emph{FreeM Extension}
3515:
3516: @node ZJOB
3517: @section ZJOB
3518: @cindex ZJOB
3519: @cindex commands, ZJOB
3520: @cindex commands, implementation-specific
3521: @cindex commands, non-standard
3522: @emph{FreeM Extension}
3523:
3524: 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.
3525:
3526: For more information, see @code{JOB}.
3527:
3528: @node ZLOAD
3529: @section ZLOAD
3530: @cindex ZLOAD
3531: @cindex commands, ZLOAD
3532: @cindex commands, implementation-specific
3533: @cindex commands, non-standard
3534: @emph{FreeM Extension}
3535:
3536: Loads routine @emph{<routine-name>} into FreeM's routine buffer, provided the optional @emph{postcondition} is @emph{true} or omitted.
3537:
3538: @emph{Syntax}
3539:
3540: @example
3541: ZLOAD@emph{:postcondition} @emph{<routine-name>}
3542: @end example
3543:
3544: @node ZNEW
3545: @section ZNEW
3546: @cindex ZNEW
3547: @cindex commands, ZNEW
3548: @cindex commands, implementation-specific
3549: @cindex commands, non-standard
3550: @emph{FreeM Extension}
3551:
3552: @node ZPRINT
3553: @section ZPRINT
3554: @cindex ZPRINT
3555: @cindex commands, ZPRINT
3556: @cindex commands, implementation-specific
3557: @cindex commands, non-standard
3558: @emph{FreeM Extension}
3559:
3560: Prints the contents of the current routine buffer, provided the optional @emph{postcondition} is @emph{true} or omitted.
3561:
3562: @emph{Syntax}
3563:
3564: @example
3565: ZPRINT@emph{:postcondition}
3566: @end example
3567:
3568: @node ZQUIT
3569: @section ZQUIT
3570: @cindex ZQUIT
3571: @cindex commands, ZQUIT
3572: @cindex commands, implementation-specific
3573: @cindex commands, non-standard
3574: @emph{FreeM Extension}
3575:
3576: In its single-argument form, quits from @emph{levels} levels of the stack, provided the optional @emph{postcondition} is @emph{true} or omitted.
3577:
3578: In its argumentless form, quits from @code{$STACK} levels of the stack, provided the optional @emph{postcondition} is @emph{true} or omitted.
3579:
3580: @emph{Syntax}
3581:
3582: @example
3583: @code{ZQUIT@emph{:postcondition} [@emph{levels}]}
3584: @end example
3585:
3586: @node ZREMOVE
3587: @section ZREMOVE
3588: @cindex ZREMOVE
3589: @cindex commands, ZREMOVE
3590: @cindex commands, implementation-specific
3591: @cindex commands, non-standard
3592: @emph{FreeM Extension}
3593:
3594: @node ZSAVE
3595: @section ZSAVE
3596: @cindex ZSAVE
3597: @cindex commands, ZSAVE
3598: @cindex commands, implementation-specific
3599: @cindex commands, non-standard
3600: @emph{FreeM Extension}
3601:
3602: @node ZTRAP
3603: @section ZTRAP
3604: @cindex ZTRAP
3605: @cindex commands, ZTRAP
3606: @cindex commands, debugging
3607: @cindex commands, implementation-specific
3608: @cindex commands, non-standard
3609: @emph{FreeM Extension}
3610:
3611: @node ZWRITE
3612: @section ZWRITE
3613: @cindex ZWRITE
3614: @cindex commands, ZWRITE
3615: @cindex commands, implementation-specific
3616: @cindex commands, non-standard
3617: @emph{FreeM Extension}
3618:
3619: Writes the names and values of M variables to @code{$IO}.
3620:
3621: @emph{Syntax}
3622:
3623: @example
3624: ZWRITE@emph{:postcondition}
3625: @end example
3626:
3627: 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.
3628:
3629: @example
3630: ZWRITE@emph{:postcondition} @emph{ArrayName},@dots{}
3631: @end example
3632:
3633: 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.
3634:
3635: @example
3636: ZWRITE@emph{:postcondition} (@emph{ArrayName},@dots{})
3637: @end example
3638:
3639: 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.
3640:
3641:
3642: @node Structured System Variables
3643: @chapter Structured System Variables
3644: @cindex variables, structured system
3645: @cindex structured system variables
3646: @cindex SSVNs
3647:
3648: @menu
3649: * ^$CHARACTER:: Character set information.
3650: * ^$DEVICE:: Device information.
3651: * ^$DISPLAY:: Information about graphic display.
3652: * ^$EVENT:: Information supplied about a synchronous or asynchronous event.
3653: * ^$GLOBAL:: Information about M globals.
3654: * ^$JOB:: Information about and control of FreeM jobs.
3655: * ^$LOCK:: Information about the FreeM lock table.
3656: * ^$OBJECT:: Information about FreeM objects.
3657: * ^$ROUTINE:: Information about FreeM routines.
3658: * ^$SYSTEM:: Information about the running system.
3659: * ^$WINDOW:: Configuration of MWAPI windows.
3660: * ^$ZPROCESS:: Information about and control of system processes.
3661: * ^$ZRPI:: Information about and control of Raspberry Pi GPIO pins.
3662: @end menu
3663:
3664: SSVN subscripts are each described in the following format:
3665:
3666: @table @asis
3667: @item @code{@emph{<ssvn-subscript-name>}} +/-R +/-U +/-D
3668: @end table
3669:
3670: 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.
3671:
3672: @node ^$CHARACTER
3673: @section ^$CHARACTER
3674: @cindex ^$CHARACTER
3675: @cindex structured system variables, ^$CHARACTER
3676:
3677: 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"}.
3678:
3679: The following values for the second subscript are supported:
3680:
3681: @table @asis
3682:
3683: @item @code{IDENT} +R -U -D
3684: Returns the empty string.
3685:
3686: @item @code{COLLATE} +R -U -D
3687: Returns the empty string.
3688:
3689: @item @code{INPUT} +R -U -D
3690: Returns the empty string if the third subscript is @code{M}, otherwise, raises error @code{M38}.
3691:
3692: @item @code{OUTPUT} +R -U -D
3693: Returns the empty string if the third subscript is @code{M}, otherwise, raises error @code{M38}.
3694:
3695: @end table
3696:
3697: @node ^$DEVICE
3698: @section ^$DEVICE
3699: @cindex ^$DEVICE
3700: @cindex structured system variables, ^$DEVICE
3701:
3702: FreeM implements several important pieces of functionality in the @code{^$DEVICE} SSVN.
3703:
3704: The first subscript of @code{^$DEVICE} represents the I/O channel of an @code{OPEN}ed device.
3705:
3706: The following values for the second subscript are supported:
3707:
3708: @table @asis
3709:
3710: @item @code{$DEVICE}
3711: Returns the value of @code{$DEVICE} for the specified I/O channel.
3712:
3713: @item @code{$X} +R -U -D
3714: Returns the horizontal cursor position of a terminal device. Only valid if the I/O channel is @code{0}.
3715:
3716: @item @code{$Y} +R -U -D
3717: Returns the vertical cursor position of a terminal device. Only valid if the I/O channel is @code{0}.
3718:
3719: @item @code{ROWS} +R -U -D
3720: Returns the number of character rows on the terminal device. Only valid if the I/O channel is @code{0}.
3721:
3722: @item @code{COLUMNS} +R -U -D
3723: Returns the number of character columns on the terminal device. Only valid if the I/O channel is @code{0}.
3724:
3725: @item @code{CHARACTER} +R -U -D
3726: Returns the character set of the specified I/O channel; always @code{M} in the current implementation.
3727:
3728: @item @code{INPUT_BUFFER} +R +U -D
3729: 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.
3730:
3731: @item @code{NAME} +R -U -D
3732: Returns the operating system's name for the file, device, or socket attached to the specified I/O channel.
3733:
3734: @item @code{FD} +R -U -D
3735: Returns the UNIX file descriptor of the specified I/O channel.
3736:
3737: @item @code{MODE} +R -U -D
3738: 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.
3739:
3740: @item @code{EOF} +R -U -D
3741: 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.
3742:
3743: @item @code{LENGTH} +R -U -D
3744: 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.
3745:
3746: @item @code{NAMESPACE} +R -U -D
3747: Returns the current @emph{mnemonic-space} in use for the referenced I/O channel. Always @code{X364} for terminals and blank for sequential files.
3748:
3749: @item @code{TYPE} +R -U -D
3750: Returns either @code{1,FILE}, @code{2,SOCKET}, or @code{4,TERMINAL}, depending on the device type associated with the specified I/O channel.
3751:
3752: @item @code{OPTIONS} -R -U -D
3753: 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:
3754:
3755: @table @asis
3756:
3757: @item @code{DSW} +R +U -D
3758: Sets or returns the current @emph{Device Status Word} controlling terminal characteristics. Only valid for I/O channel 0.
3759:
3760: @item @code{TERMINATOR} +R +U -D
3761: 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).
3762:
3763: @item @code{TERMID} +R -U -D
3764: Returns the type of terminal connected to channel 0. Only valid for I/O channel 0.
3765:
3766: @item @code{ECHO} +R +U -D
3767: 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.
3768:
3769: @item @code{DELMODE} +R +U -D
3770: 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.
3771:
3772: @item @code{ESCAPE} +R +U -D
3773: 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.
3774:
3775: @item @code{CONVUPPER} +R +U -D
3776: 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.
3777:
3778: @item @code{DELEMPTY} +R +U -D
3779: 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.
3780:
3781: @item @code{NOCTRLS} +R +U -D
3782: TBD. Only valid for I/O channel 0. Corresponds to bit 20 of the Device Status Word.
3783:
3784: @item @code{CTRLOPROC} +R +U -D
3785: 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.
3786:
3787: @item @code{NOTYPEAHEAD} +R +U -D
3788: 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.
3789: @end table
3790: @end table
3791:
3792: @emph{Example}
3793:
3794: 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.
3795:
3796: @example
3797: SET ^$JOB($JOB,"IOPATH")="/etc" ; set I/O path to /etc
3798: OPEN 1:"freem.conf/r" ; open freem.conf for reading
3799: ;
3800: ; read until we run out of lines
3801: ;
3802: FOR USE 1 READ LINE USE 0 QUIT:^$DEVICE(1,"EOF") D
3803: . WRITE LINE,!
3804: ;
3805: CLOSE 1
3806: QUIT
3807: @end example
3808:
3809: @node ^$DISPLAY
3810: @section ^$DISPLAY
3811: @cindex ^$DISPLAY
3812: @cindex structured system variables, ^$DISPLAY
3813:
3814: 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.
3815:
3816: The following second-level subscripts and specified descendant subscripts are supported:
3817:
3818: @table @asis
3819:
3820: @item @code{CLIPBOARD} +R +U +D
3821: Retrieves, sets, or erases the contents of the system clipboard.
3822:
3823: @item @code{PLATFORM} +R -U -D
3824: Retrieves the name and version of the underlying window system platform.
3825:
3826: @item @code{SIZE} +R -U -D
3827: Retrieves the display resolution of the specified graphical display. For instance, a 1080p display would have a @code{SIZE} value of @code{1920,1080}.
3828:
3829: @item @code{SPECTRUM} +R -U -D
3830: Retrieves the color depth (number of colors supported) of the specified graphical display.
3831:
3832: @item @code{COLORTYPE} +R -U -D
3833: Always returns @code{COLOR}, as monochrome and grayscale displays are not yet supported in FreeM.
3834:
3835: @item @code{UNITS} +R -U -D
3836: Returns the measurement unit of the specified display, i.e., @code{PIXEL}.
3837:
3838: @item @code{TYPEFACE} +R -U -D
3839: 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.
3840:
3841: @end table
3842:
3843: @node ^$EVENT
3844: @section ^$EVENT
3845: @cindex ^$EVENT
3846: @cindex structured system variables, ^$EVENT
3847:
3848: The @code{^$EVENT} SSVN is not yet implemented.
3849:
3850: @node ^$GLOBAL
3851: @section ^$GLOBAL
3852: @cindex ^$GLOBAL
3853: @cindex structured system variables, ^$GLOBAL
3854:
3855: The @code{^$GLOBAL} structured system variable provides information about M globals. The first-level subscript is a global name, sans the leading caret symbol.
3856:
3857: The following second-level subscripts are supported:
3858:
3859: @table @asis
3860:
3861: @item @code{BYTES} +R -U -D
3862: Returns the number of bytes this global occupies in fixed storage.
3863:
3864: @item @code{BLOCKS} +R -U -D
3865: Returns the number of blocks contained in this global.
3866:
3867: @item @code{BLOCKSIZE} +R -U -D
3868: Returns the size of data blocks for this global. Currently, FreeM only supports 1024-byte blocks.
3869:
3870: @item @code{FILE} +R -U -D
3871: Returns the full filesystem path to the data file where this global resides in fixed storage.
3872:
3873: @item @code{NAMESPACE} +R +U +D
3874: 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.
3875:
3876: @end table
3877:
3878: @node ^$JOB
3879: @section ^$JOB
3880: @cindex ^$JOB
3881: @cindex structured system variables, ^$JOB
3882:
3883: FreeM fully implements @code{^$JOB} per ANSI X11.1-1995, as well as several extensions proposed in the M Millennium Draft Standard.
3884:
3885: The first subscript of @code{^$JOB} represents the @code{$JOB} of the process.
3886:
3887: 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.
3888:
3889: The following subscripts are supported:
3890:
3891: @table @asis
3892:
3893: @item @code{GVNDEFAULT} +R +U +D
3894: Contains a default expression to be evaluated if a global variable access attempt results in an @code{M7} error.
3895:
3896: Equivalent to wrapping all global accesses in @code{$GET(@emph{global-name},@emph{string-expr})}.
3897:
3898: @item @code{LVNDEFAULT} +R +U +D
3899: Contains a default expression to be evaluated if a local variable access attempt results in an @code{M6} error.
3900:
3901: Equivalent to wrapping all local accesses in @code{$GET(@emph{global-name},@emph{string-expr})}.
3902:
3903: @item @code{LVNQOVAL} +R +U +D
3904: Contains the data value (if any) at the subscripted local variable reference from the most recent @code{$ORDER} or @code{$QUERY} operation.
3905:
3906: 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.
3907:
3908: @item @code{GVNQOVAL} +R +U +D
3909: Contains the data value (if any) at the subscripted global variable reference from the most recent @code{$ORDER} or @code{$QUERY} operation.
3910:
3911: 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.
3912:
3913: @item @code{ZCOMMANDS} +R +U -D
3914: 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.
3915:
3916: 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.
3917:
3918: If you remove a command from this list, you may provide your own private M implementation of the command in the manner described above.
3919:
3920: 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{%}.
3921:
3922: @item @code{PIPE_GLVN} +R +U -D
3923: 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{!>}.
3924:
3925: @item @code{ZCOMMAND_ARGUMENT_NAME} +R +U -D
3926: Returns or sets the variable name in which arguments to user-defined @code{Z}-commands are passed. Defaults to @code{%}.
3927:
3928: @item @code{ZFUNCTIONS} +R +U -D
3929: 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.
3930:
3931: 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.
3932:
3933: If you remove a function from this list, you may provide your own private M implementation of the function in the manner described above.
3934:
3935: @item @code{ZSVS} +R +U -D
3936: 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.
3937:
3938: 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.
3939:
3940: 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.
3941:
3942: @item @code{BREAK_HANDLER} +R +U -D
3943: Contains M code to be executed when the @code{BREAK} command is run.
3944:
3945: @item @code{ROUTINE_BUFFER_SIZE} +R +U -D
3946: 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.
3947:
3948: @item @code{ROUTINE_BUFFER_COUNT} +R +U -D
3949: 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.
3950:
3951: @item @code{ROUTINE_BUFFER_AUTO_ADJUST} +R +U -D
3952: 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.
3953:
3954: @item @code{SYMBOL_TABLE_SIZE} +R +U -D
3955: 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.
3956:
3957: @item @code{SYMBOL_TABLE_AUTO_ADJUST} +R +U -D
3958: 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.
3959:
3960:
3961: @item @code{USER_DEFINED_ISV_TABLE_SIZE} +R +U -D
3962: 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.
3963:
3964: @item @code{USER_DEFINED_ISV_TABLE_AUTO_ADJUST} +R +U -D
3965: 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.
3966:
3967: @item @code{GVN_UNIQUE_CHARS} +R +U -D
3968: Returns or sets the number of characters of a global name that make it unique, from 1 to 255.
3969:
3970: @item @code{GVN_CASE_SENSITIVE} +R +U -D
3971: 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.
3972:
3973: @item @code{GVN_NAME_SUB_LENGTH} +R +U -D
3974: Returns or sets the maximum number of characters of a global name plus all of its subscripts, from 1-255.
3975:
3976: @item @code{GVN_SUB_LENGTH} +R +U -D
3977: Returns or sets the maximum number of characters of a single global subscript, from 1-255.
3978:
3979: @item @code{SINGLE_USER} +R +U -D
1.27 snw 3980: 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 3981:
1.27 snw 3982: 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 3983:
3984: @item @code{CHARACTER} +R -U -D
3985: Returns the character set of the job.
3986:
3987: @item @code{CWD} +R +U -D
3988: Returns or sets the current working directory of the job.
3989:
3990: @item @code{OPEN} +R -U -D
3991: The @code{^$JOB($JOB,"OPEN",<channel>} subscripts list the open I/O channels in the specified job.
3992:
3993: @item @code{BERKELEYDB,FLUSH_THRESHOLD} +R +U -D
3994: 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.
3995:
3996: @item @code{EVENT} +R +U +D
3997: 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.
3998:
3999: @item @code{GLOBAL} +R -U -D
4000: Returns the global environment of the job.
4001:
4002: @item @code{IOPATH} +R +U -D
4003: Returns or sets the @emph{I/O path} to be used by the @code{OPEN} command.
4004:
4005: @item @code{PRIORITY} +R +U -D
4006: Returns or sets the @emph{nice} value of the FreeM job.
4007:
4008: @item @code{REVSTR} +R +U -D
4009: When set to 1, allows @code{$EXTRACT} to accept negative values.
4010:
4011: @item @code{ROUTINE} +R -U -D
4012: Returns the name of the routine currently being executed by the job.
4013:
4014: @item @code{SYMTAB} +R +U -D
4015: Returns or sets the current local variable symbol table in use.
4016:
4017: 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.
4018:
4019: 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")}.
4020:
4021: Setting this subscript to values other than @code{0} or @code{1} will result in a @code{ZINVEXPR} error.
4022:
4023: @item @code{$PDISPLAY} +R -U -D
4024: Returns the value of @code{$PDISPLAY} for the job.
4025:
4026: @item @code{$PRINCIPAL} +R -U -D
4027: Returns the value of @code{$PRINCIPAL} for the job.
4028:
4029: @item @code{$TLEVEL} +R -U -D
4030: Returns the current transaction level (value of @code{$TLEVEL} for the job.
4031:
4032: @item @code{$IO} +R -U -D
4033: Returns the current value of @code{$IO} for the job.
4034:
4035: @item @code{USER} +R -U -D
4036: Returns the UID of the user owning the job.
4037:
4038: @item @code{GROUP} +R -U -D
4039: Returns the GID of the group owning the job.
4040:
4041: @item @code{NAMESPACE} +R +U -D
4042: Returns or sets the name of the job's currently-active namespace.
4043:
4044: @item @code{MATH} +R +U -D
4045: 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.
4046:
4047: @code{IEEE754} mode will make mathematical calculations significantly faster, especially when accelerated by a floating-point processor, at the expense of precision and accuracy.
4048:
4049: @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.
4050:
4051: Attempting to @code{SET} this node to values other than @code{FIXED} or @code{IEEE754} will set @code{$ECODE} to @code{M29}.
4052:
4053: @end table
4054:
4055: @node ^$LOCK
4056: @section ^$LOCK
4057: @cindex ^$LOCK
4058: @cindex structured system variables, ^$LOCK
4059:
4060: 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.
4061:
4062: Attempting to @code{SET} or @code{KILL} any node in @code{^$LOCK} will raise error @code{M29}.
4063:
4064: @node ^$OBJECT
4065: @section ^$OBJECT
4066: @cindex ^$OBJECT
4067: @cindex structured system variables, ^$OBJECT
4068:
4069: @node ^$ROUTINE
4070: @section ^$ROUTINE
4071: @cindex ^$ROUTINE
4072: @cindex structured system variables, ^$ROUTINE
4073:
4074: The @code{^$ROUTINE} SSVN exposes a list of routines available in the current FreeM namespace, as well as additional attributes further describing each routine.
4075:
4076: The first-level subscript is the name of a FreeM routine minus the leading caret symbol.
4077:
4078: The following second-level subscripts are supported:
4079:
4080: @table @asis
4081:
4082: @item @code{CHARACTER} +R -U -D
4083: Returns the character set of the routine.
4084:
4085: @item @code{NAMESPACE} +R -U -D
4086: Returns the name of the FreeM namespace in which the routine resides.
4087:
4088: @item @code{PATH} +R -U -D
4089: Returns the full filesystem path to the routine in fixed storage.
4090:
4091: @end table
4092:
4093: @node ^$SYSTEM
4094: @section ^$SYSTEM
4095: @cindex ^$SYSTEM
4096: @cindex structured system variables, ^$SYSTEM
4097:
4098: The @code{^$SYSTEM} SSVN exposes system-level implementation details.
4099:
4100: The following first-level subscripts are supported:
4101:
4102: @table @asis
4103:
4104: @item @code{DEFPSIZE} +R -U -D
4105: Returns the default size in bytes of the symbol table and routine buffer memory partition.
4106:
4107: @item @code{DEFUDFSVSIZ} +R -U -D
4108: Returns the default size in bytes of the user-defined intrinsic special variable table.
4109:
4110: @item @code{DEFNSIZE} +R -U -D
4111: Returns the default size of the @code{NEW} stack, in number of entries.
4112:
4113: @item @code{MAXNO_OF_RBUF} +R -U -D
4114: Returns the maximum number of routine buffers.
4115:
4116: @item @code{DEFNO_OF_RBUF} +R -U -D
4117: Returns the default number of routine buffers.
4118:
4119: @item @code{DEFPSIZE0} +R -U -D
4120: Returns the default size in bytes of each routine buffer.
4121:
4122: @item @code{NO_GLOBLS} +R -U -D
4123: Returns the maximum number of globals that can be concurrently opened.
4124:
4125: @item @code{NO_OF_GBUF} +R -U -D
4126: Returns the number of global buffers.
4127:
4128: @item @code{NESTLEVLS} +R -U -D
4129: Returns the depth of the @code{DO}, @code{FOR}, @code{XECUTE} stack.
4130:
4131: @item @code{PARDEPTH} +R -U -D
4132: Returns the maximum depth of the parser's parameter stack.
4133:
4134: @item @code{PATDEPTH} +R -U -D
4135: Returns the maximum number of @emph{patatom}s in each pattern.
4136:
4137: @item @code{TRLIM} +R -U -D
4138: Returns the trace limit of the @code{BUILTIN} global handler.
4139:
4140: @item @code{ARGS_IN_ESC} +R -U -D
4141: Returns the maximum number of arguments in a terminal escape sequence.
4142:
4143: @item @code{ZTLEN} +R -U -D
4144: Returns the maximum length of @code{$ZTRAP}.
4145:
4146: @item @code{FUNLEN} +R -U -D
4147: Returns the maximum length of the @code{$ZF} (function key) variable.
4148:
4149: @item @code{NAME_LENGTH} +R -U -D
4150: Returns the maximum length of variable names in the current FreeM build. Compatible with the same SSVN node in @emph{Reference Standard M}
4151:
4152: @item @code{STRING_MAX} +R -U -D
4153: Returns the maximum length of character strings in the current FreeM build. Compatible with the same SSVN node in @emph{Reference Standard M}
4154:
4155: @item @code{$NEXTOK} +R -U -D
4156: 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}.
4157:
4158: @item @code{EOK} +R -U -D
4159: 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}.
4160:
4161: @item @code{OFFOK} +R -U -D
4162: 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}.
4163:
4164: @item @code{BIG_ENDIAN} +R -U -D
4165: 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}.
4166:
4167: @item @code{NAMESPACE} +R -U -D
4168: The descendant subscripts of this node list each namespace in the current FreeM environment.
4169:
4170: @item @code{MAPPINGS,GLOBAL} +R -U -D
4171: Descendant subscripts of this node represent global name mappings set in @code{^$GLOBAL(@emph{gvn},"NAMESPACE")}
4172:
4173: @end table
4174:
4175: @node ^$WINDOW
4176: @section ^$WINDOW
4177: @cindex ^$WINDOW
4178: @cindex structured system variables, ^$WINDOW
4179:
4180: 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.
4181:
4182: @node ^$ZPROCESS
4183: @section ^$ZPROCESS
4184: @cindex ^$ZPROCESS
4185: @cindex structured system variables, ^$ZPROCESS
4186:
4187: 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.
4188:
4189: The first subscript always represents the @emph{process ID} of the external process being acted upon.
4190:
4191: The following values for the second subscript are supported:
4192:
4193:
4194: @table @asis
4195:
4196: @item @code{EXISTS} +R -U -D
4197: Returns 1 if the referenced process exists; 0 otherwise.
4198:
4199: @item @code{ATTRIBUTE} +R -U -D
4200: 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.
4201:
4202: @item @code{SIGNAL} -R +U -D
4203: 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}.
4204:
4205: 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.
4206:
4207: @end table
4208:
4209: @node ^$ZRPI
4210: @section ^$ZRPI
4211: @cindex ^$ZRPI
4212: @cindex structured system variables, ^$ZRPI
4213:
4214: The @code{^$ZRPI} structured system variable provides easy access to general-purpose input/output (GPIO) pins on Raspberry Pi single-board computers.
4215:
4216: To initialize the GPIO subsystem, @code{SET ^$ZRPI("INITIALIZE")=1}.
4217:
4218: 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:
4219:
4220: @table @asis
4221:
4222: @item @code{MODE} +R +U -D
4223: Represents the operating mode of the selected pin. One of @code{INPUT}, @code{OUTPUT}, @code{PWM_OUTPUT}, or @code{GPIO_CLOCK}.
4224:
4225: @item @code{DIGITAL} +R +U -D
4226: Reads or writes the selected pin digitally. The value is limited to @code{1} or @code{0}.
4227:
4228: @item @code{ANALOG} +R +U -D
4229: Reads or writes the selected pin in an analog fashion. The value represents analog voltage.
4230:
4231: @end table
4232:
4233: @node Operators
4234: @chapter Operators
4235:
4236: @menu
4237: * Unary +:: Force a value to positive.
4238: * Unary -:: Force a value to negative.
4239: * +:: Add.
4240: * +=:: Add and assign.
4241: * ++:: Postfix increment.
4242: * -:: Subtract.
4243: * -=:: Subtract and assign.
4244: * --:: Postfix decrement.
4245: * *:: Multiply.
4246: * *=:: Multiply and assign.
4247: * /:: Divide.
4248: * /=:: Divide and assign.
4249: * \:: Integer divide.
4250: * \=:: Integer divide and assign.
4251: * #:: Modulo.
4252: * #=:: Modulo and assign.
4253: * **:: Exponentiate.
4254: * **=:: Exponentiate and assign.
4255: * <:: Less than.
4256: * <=:: Less than or equal to.
4257: * >:: Greater than.
4258: * >=:: Greater than or equal to.
4259: * _:: Concatenate.
4260: * _=:: Concatenate and assign.
4261: * =:: Equals.
4262: * [:: Contains.
4263: * ]:: Follows.
4264: * ]]:: Sorts after.
4265: * ?:: Pattern match.
4266: * &:: Logical AND.
4267: * ! (Operator):: Logical OR.
4268: * ':: Logical NOT.
4269: * @@ (Operator):: Indirect
4270: @end menu
4271:
4272: @node Unary +
4273: @section Unary +
4274: @cindex operators, unary +
4275:
4276: Forces a number to positive, whether positive or negative. Also forces numeric coercion of strings.
4277:
4278: @node Unary -
4279: @section Unary -
4280: @cindex operators, unary -
4281:
1.28 snw 4282: Forces a number to negative, whether positive or negative. Also forces numeric coercion of strings.
4283:
1.1 snw 4284: @node +
4285: @section + (Add)
4286: @cindex operators, +
4287:
1.28 snw 4288: @emph{Syntax}
4289:
4290: @example
4291: S X=1+2 ; => 3
4292: @end example
4293:
4294: Adds numbers together.
4295:
1.1 snw 4296: @node +=
4297: @section += (Add/Assign)
4298: @cindex operators, +=
4299:
1.28 snw 4300: @emph{Syntax}
4301:
4302: @example
4303: S X=5
4304: S X+=3 ; => 8
4305: @end example
4306:
4307: Increments the variable on the LHS by the value on the RHS.
4308:
1.1 snw 4309: @node ++
4310: @section ++ (Postfix Increment)
4311: @cindex operators, ++
4312:
1.28 snw 4313: Increments a variable by 1.
4314:
1.1 snw 4315: @node -
4316: @section - (Subtract)
4317: @cindex operators, -
4318:
1.28 snw 4319: Subtracts one number from another.
4320:
1.1 snw 4321: @node -=
4322: @section -= (Subtract/Assign)
4323: @cindex operators, -=
4324:
1.28 snw 4325: @emph{Syntax}
4326:
4327: @example
4328: S X=5
4329: S X-=3 ; => 2
4330: @end example
4331:
4332: Decrements the variable on the LHS by the value on the RHS.
4333:
1.1 snw 4334: @node --
4335: @section -- (Postfix Decrement)
4336: @cindex operators, --
4337:
1.28 snw 4338: Decrements the variable by one.
4339:
1.1 snw 4340: @node *
4341: @section * (Multiply)
4342: @cindex operators, *
4343:
1.28 snw 4344: Multiplies one number by another.
4345:
1.1 snw 4346: @node *=
4347: @section *= (Multiply/Assign)
4348: @cindex operators, *=
4349:
1.28 snw 4350:
4351:
1.1 snw 4352: @node /
4353: @section / (Divide)
4354: @cindex operators, /
4355:
4356: @node /=
4357: @section /= (Divide/Assign)
4358: @cindex operators, /=
4359:
4360: @node \
4361: @section \ (Integer Divide)
4362: @cindex operators, \
4363:
4364: @node \=
4365: @section \= (Integer Divide/Assign)
4366: @cindex operators, \=
4367:
4368: @node #
4369: @section # (Modulo)
4370: @cindex operators, #
4371:
4372: @node #=
4373: @section #= (Modulo/Assign)
4374: @cindex operators, #=
4375:
4376: @node **
4377: @section ** (Exponentiate)
4378: @cindex operators, **
4379:
4380: @node **=
4381: @section **= (Exponentiate/Assign)
4382: @cindex operators, **=
4383:
4384: @node <
4385: @section < (Less Than)
4386: @cindex operators, <
4387:
4388: @node <=
4389: @section <= (Less Than or Equal To)
4390: @cindex operators, <=
4391:
4392: @node >
4393: @section > (Greater Than)
4394: @cindex operators, >
4395:
4396: @node >=
4397: @section >= (Greater Than or Equal To)
4398: @cindex operators, >=
4399:
4400: @node _
4401: @section _ (Concatenate)
4402: @cindex operators, _
4403:
4404: @node _=
4405: @section _= (Concatenate/Assign)
4406: @cindex operators, _=
4407:
4408: @node =
4409: @section = (Equals)
4410: @cindex operators, =
4411:
4412: @node [
4413: @section [ (Contains)
4414: @cindex operators, [
4415:
4416: @node ]
4417: @section ] (Follows)
4418: @cindex operators, ]
4419:
4420: @node ]]
4421: @section ]] (Sorts After)
4422: @cindex operators, ]]
4423:
4424: @node ?
4425: @section ? (Pattern Match)
4426: @cindex operators, ?
4427:
4428: @node &
4429: @section & (Logical AND)
4430: @cindex operators, &
4431:
4432: @node ! (Operator)
4433: @section ! (Logical OR)
4434: @cindex operators, !
4435:
4436: @node '
4437: @section ' (Logical NOT)
4438: @cindex operators, '
4439:
4440: @node @@ (Operator)
4441: @section @@ (Indirect)
4442: @cindex operators, @@
4443:
4444: @node Routines
4445: @chapter Routines
4446: @cindex routines
4447:
4448: A @emph{routine} is a file containing M source code to be processed by FreeM.
4449:
4450: 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}).
4451:
4452: @menu
4453: * Routine Naming:: Requirements and conventions for routine names.
4454: @end menu
4455:
4456:
4457: @node Routine Naming
4458: @section Routine Naming
4459: 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.
4460:
4461: Routine naming rules are as follows:
4462:
4463: @itemize @bullet
4464: @item Routine names must begin with an upper- or lower-case letter, or a @code{%} sign
4465: @item Within the routine name, you may have upper-case or lower-case letters or digits
4466: @item The entire routine name must not be longer than 255 characters
4467: @end itemize
4468:
4469: Routines whose names begin with @code{%} must be located in the @code{SYSTEM} namespace. Other routines may be located in any namespace.
4470:
4471: @node Types
4472: @chapter Types
4473: @cindex types
4474: @cindex data types
4475:
4476: 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.
4477:
4478: @menu
4479: * BOOLEAN:: Truth values.
4480: * COMPLEX:: Numbers with real and imaginary parts.
4481: * INTEGER:: Numbers with no decimal part.
4482: * REAL:: Numbers with a decimal part.
4483: * STRING:: Arbitrary strings of characters.
4484: * Custom Types (Classes):: User-defined, object-oriented types.
4485: @end menu
4486:
4487: @node BOOLEAN
4488: @section BOOLEAN
4489: @cindex data types, BOOLEAN
4490: @cindex types, BOOLEAN
4491:
4492: The @code{BOOLEAN} type represents any M value that can be interpreted as a truth-value.
4493:
4494: @node COMPLEX
4495: @section COMPLEX
4496: @cindex data types, COMPLEX
4497: @cindex types, COMPLEX
4498:
4499: 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.
4500:
4501: 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}.
4502:
4503: @node INTEGER
4504: @section INTEGER
4505: @cindex data types, INTEGER
4506: @cindex types, INTEGER
4507:
4508: An @code{INTEGER} is an interpretation of numeric data with any fractional part removed.
4509:
4510: @node REAL
4511: @section REAL
4512: @cindex data types, REAL
4513: @cindex types, REAL
4514:
1.29 snw 4515: A @code{REAL} is a numeric interpretation of data including a fractional part.
4516:
1.1 snw 4517: @node STRING
4518: @section STRING
4519: @cindex data types, STRING
4520: @cindex types, STRING
4521:
1.36 snw 4522: The @code{STRING} is the fundamental FreeM data type. Other types are inferred from the context of their usage.
4523:
4524: @subsection String Rules
4525:
4526: The following rules apply to all FreeM strings:
4527:
4528: @itemize
4529: @item Must not exceed 255 characters
4530: @item Must not contain @code{$C(0)}, @code{$C(201)}, or @code{$C(202)}
4531: @end itemize
4532:
4533: @subsection String Quoting Rules
4534: Strings in FreeM must be surrounded in double quotes:
4535:
4536: @example
4537: SET MYSTRING="This is a string literal"
4538: @end example
4539:
4540: If you want to include double quotes inside of a string, simply double them:
4541:
4542: @example
4543: SET MYSTRING="This is a ""string literal"" with embedded double quotes"
4544: @end example
4545:
1.29 snw 4546:
1.1 snw 4547: @node Custom Types (Classes)
4548: @section Custom Types (Classes)
4549: @cindex data types, custom
4550: @cindex types, custom
4551: @cindex classes
4552:
4553: See @ref{Classes}.
4554:
4555: @node Globals
4556: @chapter Globals
4557: @cindex globals
4558: @cindex variables, global
4559: @cindex data
4560:
1.33 snw 4561: @menu
4562: * Globals Overview:: Basics of FreeM persistent storage.
4563: * Creating Globals:: How to create globals.
4564: * Removing Globals:: How to remove globals.
4565: * Global Storage:: How globals are stored.
4566: @end menu
4567:
4568: @node Globals Overview
4569: @section Globals Overview
4570:
1.31 snw 4571: 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.
4572:
4573: Each global comprises three elements:
4574:
4575: @itemize @bullet
4576: @item
4577: An alphabetic name beginning with a caret (@code{^}) or a caret and a percent sign (@code{^%})
4578: @item
4579: Optionally, one or more comma-delimited subscripts, enclosed in parentheses
4580: @item
4581: A value of up to 255 characters in length
4582: @end itemize
4583:
1.36 snw 4584: 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 4585:
4586: @node Creating Globals
4587: @section Creating Globals
4588: @cindex globals, creating
4589:
4590: To create a global, you can use the @code{SET} command:
4591:
4592: @example
4593: SET ^MYGLOBAL("foo","bar")="this is the data value"
4594: @end example
4595:
4596: @node Removing Globals
4597: @section Removing Globals
4598: @cindex globals, removing
4599:
4600: To remove an entire global, you can use the @code{KILL} command with the unsubscripted name of the global:
4601:
4602: @example
4603: KILL ^MYGLOBAL
4604: @end example
4605:
4606: 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:
4607:
4608: @example
4609: KILL ^MYGLOBAL("foo")
4610: @end example
4611:
4612: This will remove only the @code{"foo"} subscript and all of its children.
4613:
4614: If you only want to remove the data value at a specific subscript level, leaving the subscript itself intact, use @code{KVALUE}:
4615:
4616: @example
4617: KVALUE ^MYGLOBAL("foo")
4618: @end example
4619:
4620: @node Global Storage
4621: @section Global Storage
4622: @cindex globals, storage
4623:
4624: FreeM globals are stored in @code{$PREFIX/var/freem/@emph{<environment-name>}/@emph{<namespace-name>}/globals} in a binary format.
4625:
4626: Global files have a header of the following format:
4627:
4628: @verbatim
4629: typedef struct global_header {
4630:
4631: char magic[5]; /* FRMGL */
4632: int format_version;
4633: char host_triplet[40];
4634: char host_id[256];
4635:
4636: unsigned long block_size;
4637: unsigned long last_transaction_id;
4638:
4639: long created;
4640: long last_backup;
4641:
4642: } global_header;
4643: @end verbatim
4644:
1.1 snw 4645: @node Concurrency Control
4646: @chapter Concurrency Control
4647: @cindex concurrency control
4648: @cindex locking
4649: @cindex transaction processing
4650:
1.33 snw 4651: @menu
4652: * Concurrency Control Overview:: Basics of concurrency control.
4653: * Advisory Locks:: Coordinating access voluntarily.
4654: * Transaction Processing:: Ensuring logical consistency.
4655: @end menu
4656:
4657: @node Concurrency Control Overview
4658: @section Concurrency Control Overview
4659:
1.34 snw 4660: 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 4661:
1.34 snw 4662: In FreeM, there are two mechanisms provided for managing concurrent global access: @emph{advisory locks}, and @emph{transaction processing}.
4663:
4664: 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.
4665:
4666: 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 4667:
1.33 snw 4668: @node Advisory Locks
4669: @section Advisory Locks
4670:
1.31 snw 4671: @node Transaction Processing
4672: @section Transaction Processing
4673: @cindex transaction processing
4674:
4675: 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 concurrency is not disturbed), or in serial mode (where writes are guaranteed to be atomic, consistent, isolated, and durable).
4676:
4677: @subsection Theory of Operation
4678:
4679: 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.
4680:
4681: 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.
4682:
4683: 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.
4684:
4685: Checkpoints can have one of two modes:
4686:
4687: @table @asis
4688:
4689: @item @code{CP_REMOVE}
4690: 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.
4691:
4692: @item @code{CP_RESTORE}
4693: 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.
4694:
4695: @end table
4696:
4697: The below example shows a few global operations and checkpoints for a transaction in-flight using the @code{trantab} direct-mode command:
4698:
4699: @verbatim
4700: TL1:DEFAULT.USER> trantab
4701: $TLEVEL 1*
4702: Operations for Transaction ID: 6ea14aad-b8f1-47f9-9f52-4f513f892bc0 [RESTARTABLE SERIAL]
4703:
4704: OP. NO. ACTION KEY/DATA
4705: ------- ------ --------
4706: 1 SET ^FOO=3
4707: 2 KILL ^FOO
4708: 3 SET ^snw=10
4709: 4 SET ^BRANDNEW=6
4710:
4711: Global checkpoints:
4712:
4713: GLOBAL MODE FILES
4714: ------ ---- -----
4715: ^BRANDNEW CP_REMOVE IN: /usr/local/var/freem/USER/globals/^BRANDNEW
4716: ^snw CP_RESTORE IN: /usr/local/var/freem/USER/globals/^snw
4717: OUT: /usr/local/var/freem/USER/globals/^snw.23390.1.chk
4718: ^FOO CP_RESTORE IN: /usr/local/var/freem/USER/globals/^FOO
4719: OUT: /usr/local/var/freem/USER/globals/^FOO.23390.1.chk
4720: @end verbatim
4721:
4722: 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.
4723:
4724: @subsection Using Transaction Processing
4725:
4726: To use transactions in FreeM, you need to be familiar with three commands:
4727:
4728: @itemize @bullet
4729: @item
4730: @code{TSTART}
4731: @item
4732: @code{TCOMMIT}
4733: @item
4734: @code{TROLLBACK}
4735: @end itemize
4736:
4737: With transaction processing, global variable operations occurring between @code{TSTART} and @code{TCOMMIT} commands will be contained within the transaction.
4738:
4739: The atomicity, consistency, isolation, and durability facets of FreeM transaction hinge on the transaction mode.
4740:
4741: @subsubsection BATCH Transactions
4742: @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.
4743:
4744: 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.
4745:
4746: @subsubsection SERIAL Transactions
4747: @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).
4748:
1.1 snw 4749: @node Local Variables
4750: @chapter Local Variables
4751: @cindex variables, local
4752: @cindex local variables
4753:
4754: @node Scoping
4755: @chapter Scoping
4756: @cindex scoping
4757:
4758: @node Decision Constructs
4759: @chapter Decision Constructs
4760: @cindex decision constructs
4761: @cindex IF
4762: @cindex ELSE
4763: @cindex THEN
4764: @cindex postconditionals
4765:
4766: @node Branch Constructs
4767: @chapter Branch Constructs
4768: @cindex branch constructs
4769: @cindex DO
4770: @cindex GOTO
4771: @cindex JOB
4772:
4773: @node Loop Constructs
4774: @chapter Loop Constructs
4775: @cindex loop constructs
4776: @cindex FOR
4777:
4778: @node Modular Programming
4779: @chapter Modular Programming
4780: @cindex modular programming
4781: @cindex functions, extrinsic
4782: @cindex subroutines
4783:
1.2 snw 4784: @menu
4785: * Subroutines:: Making sections of code reusable.
4786: * Extrinsic Functions:: Reusable code that returns a value.
4787: @end menu
4788:
1.1 snw 4789: @node Subroutines
4790: @section Subroutines
4791:
4792: @node Extrinsic Functions
4793: @section Extrinsic Functions
4794:
4795: @node Object-Oriented Programming
4796: @chapter Object-Oriented Programming
4797: @cindex object-oriented programming
4798: @cindex programming, object-oriented
4799:
1.2 snw 4800: @menu
1.29 snw 4801: * Classes:: The basis of object-oriented programming.
4802: * Inheritance:: Basing one class upon another.
4803: * Methods:: Attaching code to a class.
4804: * Public and Private Variables:: Managing class member access.
1.31 snw 4805: * Instantiating Objects:: Creating instances of classes.
4806: * Determining Object Class:: Getting object information at runtime.
1.2 snw 4807: @end menu
4808:
1.1 snw 4809: @node Classes
4810: @section Classes
4811:
1.33 snw 4812: @menu
4813: * Class Overview:: Class basics.
4814: * Constructors:: Managing object creation.
4815: * Destructors:: Cleaning up.
4816: * Runtime Polymorphism:: Selecting methods at runtime.
4817: @end menu
4818:
4819: @node Class Overview
4820: @subsection Class Overview
4821:
1.29 snw 4822: 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:
4823:
4824: @example
4825: MYCLASS(THIS,INIT):OBJECT ; Constructor for MYCLASS, inherits OBJECT
4826: ; two private variables
4827: S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
4828: S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
4829: Q
4830: ;
4831: DESTROY(THIS) ; This is the destructor
4832: Q
4833: @end example
4834:
4835: The above example demonstrates general class syntax.
4836:
4837: @node Constructors
4838: @subsection Constructors
4839:
4840: A @emph{constructor} is an M entry point that is called when a new instance of a class is created.
4841:
4842: 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}.
4843:
4844: @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.
4845:
4846: A constructor looks like this:
4847:
4848: @example
4849: %FRACTION(THIS,INIT):OBJECT ;
4850: S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
4851: S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
4852: Q
4853: @end example
4854:
4855: @emph{Syntax}
4856: @example
4857: @emph{<class-name>}(THIS,INIT)[:@emph{<superclass>}]
4858: @end example
4859:
4860: 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}.
4861:
4862: @node Destructors
4863: @subsection Destructors
4864: 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}).
4865:
4866: The destructor should be used to clean up any resources used by class methods.
4867:
4868: A destructor looks like this:
4869:
4870: @example
4871: DESTROY(THIS) ;
4872: ; free any resources that should be freed at the end of the object's lifetime
4873: Q
4874: @end example
1.2 snw 4875:
1.1 snw 4876: @node Inheritance
1.29 snw 4877: @section Inheritance
4878:
4879: Every class you create will automatically inherit the methods and functionality of the @code{OBJECT} class, supplied with FreeM.
4880:
4881: 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.
4882:
4883: Inheritance is achieved by specifying the name of the superclass in the constructor:
4884:
4885: @example
4886: CLASS(THIS,INIT):SUPERCLASS
4887: @end example
4888:
4889: @node Runtime Polymorphism
4890: @subsection Runtime Polymorphism
4891:
4892: 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.
4893:
4894: 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 4895:
4896: @node Methods
1.29 snw 4897: @section Methods
4898: 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 4899:
1.29 snw 4900: The following class (@code{MYCLASS}) has a constructor, a destructor, and a method called @code{MYMETHOD}:
4901:
4902: @example
4903: %MYCLASS(THIS,INIT) ;
4904: Q THIS
4905: DESTROY(THIS) ;
4906: Q
4907: MYMETHOD(THIS) ;
4908: Q "VALUE"
4909: @end example
4910:
1.31 snw 4911: The dot operator is used to invoke class methods:
4912:
4913: @example
4914: DEFAULT.USER> N MYOBJ=$#^%MYCLASS("")
4915: DEFAULT.USER> W MYOBJ.MYMETHOD()
4916: VALUE
4917: @end example
4918:
1.29 snw 4919: @node Public and Private Variables
4920: @section Public and Private Variables
4921:
1.30 snw 4922: 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 4923:
4924: The below constructor for a @code{FRACTION} class defines two private fields:
4925:
4926: @example
4927: %FRACTION(THIS,INIT):OBJECT ;
4928: S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
4929: S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
4930: Q
4931: @end example
4932:
4933: Either of the following commands will create a public field:
4934:
4935: @example
4936: S THIS("VARNAM")="Initial Value"
4937: S THIS("VARNAM"):PUBLIC="Initial Value"
4938: @end example
1.1 snw 4939:
1.29 snw 4940: Attempting to access private fields from outside of the class will raise error condition @code{ZOBJFLDACCV}.
1.1 snw 4941:
1.31 snw 4942: @node Instantiating Objects
4943: @section Instantiating Objects
4944:
4945: To instantiate an object (i.e., create an object from a certain class), you will use the @code{NEW} command as follows:
4946:
4947: @example
4948: NEW MYSTR=$#^%STRING("myString")
4949: @end example
4950:
4951: This will create a local variable called MYSTR of type STRING, and initialize it with the value myString.
4952:
4953: @node Determining Object Class
4954: @section Determining Object Class
4955:
4956: To determine the class of any FreeM local variable, you will use the @code{$$TYPE()} method:
4957:
4958: @example
4959: USER> W MYSTR.$$TYPE()
4960: ^%STRING
4961: @end example
4962:
4963: The @code{$$TYPE()} method is a member of the @code{OBJECT} class.
4964:
1.1 snw 4965: @node Libraries
4966: @chapter Libraries
4967: @cindex libraries
4968:
4969: @node Sequential I/O
4970: @chapter Sequential I/O
4971:
4972: @node Network I/O
4973: @chapter Network I/O
4974: @cindex networks, input and output
4975:
4976: 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.
4977:
4978: @section Opening and Connecting a Client Socket
4979: @cindex networks, opening and connecting client sockets
4980:
4981: To open a client socket and connect to it, you will need to call the @code{OPEN} command and the @code{USE} command:
4982:
4983: @example
4984: ;
4985: ; Set socket read terminator to LF
4986: ;
4987: SET ^$DEVICE(100,"OPTIONS","TERMINATOR")=$C(10)
4988: ;
4989: ; Open an IPv4 TCP socket to mail.mydomain.com on port 25 (SMTP)
4990: ; and connect to it
4991: ;
4992: OPEN 100:"mail.mydomain.com:25:IPV4:TCP"
4993: USE 100:/CONNECT
4994: ;
4995: ; Read a line of input from the remote host and write it to the terminal
4996: ;
4997: NEW LINE
4998: READ LINE
4999: USE 0
5000: WRITE LINE,!
5001: ;
5002: ; CLOSE the socket and disconnect
5003: ;
5004: CLOSE 100
5005: QUIT
5006: @end example
5007:
5008: @node Extended Global References
5009: @chapter Extended Global References
5010: @cindex global references, extended
5011: @cindex extended global references
5012:
5013: @section Standard Extended Global References
5014: @cindex extended global references, standard
5015:
5016: 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.
5017:
5018: 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:
5019:
5020: @example
5021: WRITE ^|"VISTA"|VA(200,0),!
5022: @end example
5023:
5024: You may also use an expression that resolves to a string containing a valid namespace name:
5025:
5026: @example
5027: SET NS="VISTA"
5028: WRITE ^|NS|VA(200,0),!
5029: @end example
5030:
5031: @node Global Aliasing
5032: @chapter Global Aliasing
5033: @cindex aliasing, global
5034: @cindex globals, aliasing
5035:
5036: FreeM provides the ability to set alternative names for M global variables.
5037:
5038: To create an alias of @code{^FOO} named @code{^BAR}, use the following command:
5039:
5040: @example
5041: SET ^$JOB($JOB,"ALIASES","^BAR")="^FOO"
5042: @end example
5043:
5044: 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.
5045:
5046: @node Global Mappings
5047: @chapter Global Mappings
5048: @cindex mappings, global
5049: @cindex globals, mapping
5050:
5051: 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.
5052:
5053: To map the @code{^FOO} global to the @code{SYSTEM} namespace, any of the following will work:
5054:
5055: @example
5056: MAP GLOBAL ^FOO="SYSTEM"
5057: SET ^$GLOBAL("FOO","NAMESPACE")="SYSTEM"
5058: SET ^$SYSTEM("MAPPINGS","GLOBAL","^FOO")="SYSTEM"
5059: @end example
5060:
5061: There is no functional difference in any of the three approaches; the method you choose is a matter of personal preference.
5062:
5063: To remove the above mapping, any of the following examples will also work:
5064:
5065: @example
5066: UNMAP GLOBAL ^FOO
5067: KILL ^$GLOBAL("FOO","NAMESPACE")
5068: KILL ^$SYSTEM("MAPPINGS","GLOBAL","^FOO")
5069: @end example
5070:
5071:
5072:
5073: @node Asynchronous Event Handling
5074: @chapter Asynchronous Event Handling
5075: @cindex event handling, asynchronous
5076:
5077: Asynchronous event handling in FreeM follows the specifications of the unpublished MDC @emph{Millennium Draft Standard}.
5078:
5079: @section Setting Up Async Event Handlers
5080:
5081: 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:
5082:
5083: @table @emph
5084:
5085: @item Event Classes
5086: @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.
5087:
5088: @item Event Identifiers
5089: @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}).
5090:
5091: @item Event Handlers
5092: @emph{Event handlers} are M routines or subroutines that can be registered to run when an event of a certain event class occurs.
5093:
5094: @item Event Registration
5095: @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.
5096:
5097: @item Event Blocking and Unblocking
5098: @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.
5099:
5100: @end table
5101:
5102: The following sections of this chapter will take you step-by-step through setting up an event handler for @code{SIGWINCH} signal handling.
5103:
5104: @section Registering an Asynchronous Event Handler
5105: @cindex event handlers, registration
5106:
5107: To register a job-specific event handler that will only execute in the current FreeM process, use the following syntax:
5108:
5109: @example
5110: SET ^$JOB($JOB,"EVENT",@emph{event-class},@emph{event-identifier})=@emph{entryref}
5111: @end example
5112:
5113: To register a system-wide event handler that will execute in every FreeM process, use the following syntax:
5114:
5115: @example
5116: SET ^$SYSTEM("EVENT",@emph{event-class},@emph{event-identifier})=@emph{entryref}
5117: @end example
5118:
5119: For example, use the following to register @code{^RESIZE} as an asynchronous event handler for @code{SIGWINCH} events:
5120:
5121: @example
5122: SET ^$JOB($JOB,"EVENT","INTERRUPT","SIGWINCH")="^RESIZE"
5123: @end example
5124:
5125: This by itself will not enable asynchronous event handling, as it merely @emph{registers} an event handler, associating it with event class @code{INTERRUPT} and event identifier @code{SIGWINCH}.
5126:
5127: @section Enabling Asynchronous Event Handling
5128: @cindex event handlers, enabling
5129:
5130: In order to enable asyncronous event handling, the @code{ASTART} command is used. In the following example, we will enable asynchronous event handling for the @code{INTERRUPT} event class:
5131:
5132: @example
5133: ASTART "INTERRUPT"
5134: @end example
5135:
5136: Omitting the @code{"INTERRUPT"} argument will enable asynchronous event handling for @emph{all} event classes. See @code{ASTART} in the commands section for more details.
5137:
5138: Once this is done, any event handlers registered for the @code{INTERRUPT} event class in @code{^$JOB} will be executed asynchronously as appropriate.
5139:
5140: 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.
5141:
5142: @section Disabling Asynchronous Event Handling
5143: @cindex event handlers, disabling
5144:
5145: 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:
5146:
5147: @example
5148: ASTOP "INTERRUPT"
5149: @end example
5150:
5151: 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.
5152:
5153: You may also disable asynchronous event handling for a specific event identifier by @code{KILL}ing the appropriate node in the @code{^$JOB} SSVN, which unregisters the event handler altogether. The following example will unregister the event handler for the @code{SIGWINCH} event identifier:
5154:
5155: @example
5156: KILL ^$JOB($JOB,"EVENT","INTERRUPT","SIGWINCH")
5157: @end example
5158:
5159: @section Temporarily Blocking Asynchronous Event Handling
5160: @cindex event handlers, blocking
5161:
5162: 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.
5163:
5164: The following example blocks asynchronous event handling for the @code{INTERRUPT} event class:
5165:
5166: @example
5167: ABLOCK "INTERRUPT"
5168: @end example
5169:
5170: 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.
5171:
5172: 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.
5173:
5174: @node Global Triggers
5175: @chapter Global Triggers
5176: @cindex global triggers
5177: @cindex triggers
5178:
5179: 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.
5180:
5181: 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:
5182:
5183: @table @asis
5184:
5185: @item @code{DATA}
5186: Trigger will fire when the @code{$DATA} intrinsic function is called on @emph{<gvn>}.
5187:
5188: @item @code{GET}
5189: Trigger will fire when @emph{<gvn>} is read from.
5190:
5191: @item @code{INCREMENT}
5192: Trigger will fire when intrinsic function @code{$INCREMENT} is called on @emph{<gvn>}.
5193:
5194: @item @code{KILL}
5195: Trigger will fire when @emph{<gvn>} is @code{KILL}ed.
5196:
5197: @item @code{NEXT}
5198: Trigger will fire when intrinsic function @code{$NEXT} is called on @emph{<gvn>}.
5199:
5200: @item @code{ORDER}
5201: Trigger will fire when intrinsic function @code{$ORDER} is called on @emph{<gvn>}.
5202:
5203: @item @code{QUERY}
5204: Trigger will fire when intrinsic function @code{$QUERY} is called on @emph{<gvn>}.
5205:
5206: @item @code{SET}
5207: Trigger will fire when @code{SET @emph{<gvn>}=@emph{value}} occurs.
5208:
5209: @item @code{ZDATA}
5210: Trigger will fire when intrinsic function @code{ZDATA} is called on @emph{<gvn>}.
5211:
5212: @end table
5213:
5214: When a @code{TRIGGER} event occurs, the @code{"GLOBAL"} node of the @code{^$EVENT} structured system variable will be populated with the global reference that invoked the trigger event.
5215:
5216: If a @code{SET} or @code{KILL} trigger was the source of the @code{TRIGGER} event, the @code{OLD_VALUE} node of @code{^$EVENT} will be populated with original value of @code{^$EVENT("GLOBAL")} prior to the change, and @code{NEW_VALUE} will be populated with the new value. This allows triggers to contain logic to undo global changes. This functionality can also be used to provide auditing of specific global changes.
5217:
5218: The following example shows a trigger implemented for @code{SET} operations on the @code{^DD} global.
5219:
5220: @example
5221: TRIGGER ;
5222: ;
5223: ; Set up a SET trigger on ^DD
5224: ;
5225: SET ^$JOB($JOB,"EVENT","TRIGGER","SET:^DD")="ONSET^TRIGGER"
5226: ;
5227: ; Enable the TRIGGER event class
5228: ;
5229: ASTART "TRIGGER"
5230: ;
5231: ; Try setting a node in ^DD
5232: ;
5233: SET ^DD(1)="Test"
5234: ;
5235: ; Quit
5236: ;
5237: QUIT
5238: ;
5239: ;
5240: ONSET ;
5241: WRITE "The "_^$EVENT("GLOBAL")_" global node was SET.",!
5242: QUIT
5243: @end example
5244:
5245: 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($JOB,"EVENT","TRIGGER",...)}.
5246:
5247: @node Synchronous Event Handling
5248: @chapter Synchronous Event Handling
5249:
5250: @node GUI Programming with MWAPI
5251: @chapter GUI Programming with MWAPI
5252:
5253: @node User-Defined Z Commands
5254: @chapter User-Defined Z Commands
5255:
5256: @node User-Defined Z Functions
5257: @chapter User-Defined Z Functions
5258:
5259: @cindex z functions, user-defined
5260:
5261: @node User-Defined SSVNs
5262: @chapter User-Defined SSVNs
5263:
5264: @cindex structured system variables, user-defined
5265: @cindex structured system variables
5266:
5267: @node Language Dialects
5268: @chapter Language Dialects
5269:
5270: @cindex language dialects
5271: @cindex dialects, language
5272:
5273:
5274: @node System Library Routines
5275: @chapter System Library Routines
5276: @cindex system library routines
5277:
5278: @section ^%ZCOLUMNS
5279: @cindex ^%ZCOLUMNS
5280: @cindex system library routines, ^%ZCOLUMNS
5281:
5282: This routine is the implementation of the @code{$ZCOLUMNS} intrinsic special variable.
5283:
1.28 snw 5284: @section %SYSINIT
5285: @cindex %SYSINIT
5286: @cindex system library routines, %SYSINIT
1.1 snw 5287:
5288: This routine is the default startup routine for FreeM running in direct mode.
5289:
5290: Running @code{DO INFO} from direct mode will use this routine to display information about the current FreeM status and namespace configuration.
5291:
5292: @section ^%ZHELP
5293: @cindex ^%ZHELP
5294: @cindex system library routines, ^%ZHELP
5295:
5296: 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}.
5297:
5298: @section ^%ZROWS
5299: @cindex ^%ZROWS
5300: @cindex system library routines, ^%ZROWS
5301:
5302: This routine is the implementation of the @code{$ZROWS} intrinsic special variable.
5303:
5304: @node Interrupt Handling
5305: @chapter Interrupt Handling
5306: @cindex interrupt handling
5307:
1.22 snw 5308: When FreeM receives the @code{SIGINT} signal, either by pressing @code{Ctrl-C} during program execution, or by external signal from the operating system, the FreeM environment daemon, or another external process, one of two things can happen, depending on the state of the @code{$ZI} special variable:
1.1 snw 5309:
5310: @table @asis
5311: @item @code{$ZI} evaluates @emph{true}
5312: In this case, the @code{ZINRPT} error is raised, and normal error handling procedures apply. If neither @code{$ZTRAP} nor @code{$ETRAP} are set, FreeM prints an error diagnostic on the home device and will exit the FreeM process in application mode (i.e., the @code{freem} executable was started with the @code{--routine} or @code{-r} flag), or return to the direct mode prompt otherwise.
5313:
5314: This is the default behavior of FreeM.
5315: @item @code{$ZI} evaluates @emph{false}
5316: 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.
5317:
5318: Checking the value of @code{$ZCONTROLC} will reset it to @emph{false}.
5319: @end table
5320:
5321: In either case, if asynchronous event handling is enabled for the @code{INTERRUPT} event class (i.e., @code{ASTART "INTERRUPT"} or @code{ASTART} have been invoked by the current process), an asynchronous event of event class @code{INTERRUPT} and event identifier @code{SIGINT} will be enqueued.
5322:
5323: @node Error Processing
5324: @chapter Error Processing
5325: @cindex error processing
5326:
5327: FreeM exposes three means of processing M program execution errors:
5328:
5329: @table @emph
5330:
5331: @item FreeM-style error processing
5332: FreeM-style error processing exposes a read/write error trap in @code{$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.
5333:
5334: @item DSM 2.0-style error processing
5335: 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.
5336:
5337: @item Standard error processing
5338: 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.
5339:
5340: 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.
5341:
5342: @end table
5343:
5344: For further information on switching between FreeM-style and DSM 2.0-style @code{$ZTRAP} error handling, see the documentation for the @code{BREAK} command.
5345:
5346: @node FreeM Error Codes
5347: @chapter FreeM Error Codes
5348: @cindex Error Codes
5349:
5350: @table @asis
5351:
5352: @item @code{ZINRPT} - @emph{interrupt}
5353: Raised when an interrupt signal is received.
5354:
5355: @item @code{ZBKERR} - @emph{BREAK point}
5356: Raised when a @code{BREAK} point is reached.
5357:
5358: @item @code{ZNOSTAND} - @emph{non standard syntax}
5359: Raised when features incompatible with the current value of @code{$DIALECT} are used.
5360:
5361: @item @code{ZUNDEF} - @emph{variable not found}
5362: 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}.
5363:
5364: @item @code{ZLBLUNDEF} - @emph{label not found}
5365: Raised when a referenced label is not found.
5366:
5367: @item @code{ZMISSOPD} - @emph{missing operand}
5368: Raised when an operand is missing from an expression.
5369:
5370: @item @code{ZMISSOP} - @emph{missing operator}
5371: Raised when an operator is missing from an expression.
5372:
5373: @item @code{ZILLOP} - @emph{unrecognized operator}
5374: Raised when an unrecognized operator is encountered in an expression.
5375:
5376: @item @code{ZQUOTER} - @emph{unmatched quotes}
5377: Raised when unbalanced quotes are encountered.
5378:
5379: @item @code{ZCOMMAER} - @emph{comma expected}
5380: Raised when a comma is expected in program syntax but is not found.
5381:
5382: @item @code{ZASSIGNER} - @emph{equals '=' expected}
5383: Raised when an equals sign is expected in program syntax but is not found.
5384:
5385: @item @code{ZARGER} - @emph{argument not permitted}
5386: Raised when an argument is encountered in a syntactic position where arguments are not permitted.
5387:
5388: @item @code{ZSPACER} - @emph{blank ' ' expected}
5389: Raised when a space character is expected in program syntax but is not found.
5390:
5391: @item @code{ZBRAER} - @emph{unmatched parentheses}
5392: Raised when unbalanced parentheses are detected in program syntax.
5393:
5394: @item @code{ZLVLERR} - @emph{level error}
5395: Raised when a level error occurs.
5396:
5397: @item @code{ZDIVER} - @emph{divide by zero}
5398: Raised when program code attempts to divide by zero. Deprecated in favor of standard error code @code{M9}.
5399:
5400: @item @code{ZILLFUN} - @emph{function not found}
5401: Raised when program code attempts to call intrinsic or extrinsic functions that are not defined.
5402:
5403: @item @code{ZFUNARG} - @emph{wrong number of function arguments}
5404: Raised when an intrinsic or extrinsic function is called with the wrong number of arguments.
5405:
5406: @item @code{ZZTERR} - @emph{ZTRAP error}
5407: Raised when a @code{$ZTRAP} error occurs.
5408:
5409: @item @code{ZNEXTERR} - @emph{$NEXT/$ORDER error}
5410: Raised when an error occurs in @code{$NEXT} or @code{$ORDER}.
5411:
5412: @item @code{ZSELER} - @emph{$SELECT error}
5413: Raised when an error occurs in @code{$SELECT}
5414:
5415: @item @code{ZCMMND} - @emph{illegal command}
5416: Raised when program code attempts to execute an illegal command.
5417:
5418: @item @code{ZARGLIST} - @emph{argument list incorrect}
5419: Raised when the argument list supplied to an M language element does not match that language element's syntactic requirements.
5420:
5421: @item @code{ZINVEXPR} - @emph{invalid expression}
5422: Raised when an invalid expression is encountered.
5423:
5424: @item @code{ZINVREF} - @emph{invalid reference}
5425: Raised when an invalid variable reference is encountered.
5426:
5427: @item @code{ZMXSTR} - @emph{string too long}
5428: Raised when a string is encountered that exceeds @code{^$SYSTEM("STRING_MAX")}.
5429:
5430: @item @code{ZTOOPARA} - @emph{too many parameters}
5431: Raised when too many parameters are passed to a function or subroutine.
5432:
5433: @item @code{ZNOPEN} - @emph{unit not open}
5434: Raised when attempting to access an I/O channel that has not been opened.
5435:
5436: @item @code{ZNODEVICE} - @emph{unit does not exist}
5437: Raised when attempting to access a device that does not exist.
5438:
5439: @item @code{ZPROTECT} - @emph{file protection violation}
5440: Raised when attempting to access a file or device to which you do not have permission.
5441:
5442: @item @code{ZGLOBER} - @emph{global not permitted}
5443: Raised when attempting to use a global in a syntactic element where global variables are not permitted.
5444:
5445: @item @code{ZFILERR} - @emph{file not found}
5446: Raised when attempting to access a file that does not exist.
5447:
5448: @item @code{ZPGMOV} - @emph{program overflow}
5449: Raised when a program overflows the limits of a routine buffer.
5450:
5451: @item @code{ZSTKOV} - @emph{stack overflow}
5452: Raised when @code{DO}, @code{FOR}, or @code{XECUTE} nesting levels exceed the value in @code{^$SYSTEM("NESTLEVLS")}.
5453:
5454: @item @code{ZSTORE} - @emph{symbol table overflow}
5455: Raised when program code attempts to store too much data in the local symbol table. Should not occur unless symbol table auto-adjust is disabled.
5456:
5457: @item @code{ZNOREAD} - @emph{file won't read}
5458: Raised when program code attempts to read from an unreadable file.
5459:
5460: @item @code{ZNOWRITE} - @emph{file won't write}
5461: Raised when program code attempts to write to an unwritable file.
5462:
5463: @item @code{ZNOPGM} - @emph{routine not found}
5464: Raised when an attempt is made to load or execute a routine that does not exist in the current namespace.
5465:
5466: @item @code{ZNAKED} - @emph{illegal naked reference}
5467: Raised when an attempt is made to use an illegal naked reference.
5468:
5469: @item @code{ZSBSCR} - @emph{illegal subscript}
5470: Raised when an illegal subscript access is attempted.
5471:
5472: @item @code{ZISYNTX} - @emph{insert syntax}
5473: Raised when illegal insert syntax is used.
5474:
5475: @item @code{ZDBDGD} - @emph{global data degradation}
5476: Raised when corruption is detected in global data files.
5477:
5478: @item @code{ZKILLER} - @emph{job kill signal}
5479: Raised on a job kill signal.
5480:
5481: @item @code{ZHUPER} - @emph{hangup signal}
5482: Raised on a job hangup signal.
5483:
5484: @item @code{ZMXNUM} - @emph{numeric overflow}
5485: Raised when an assignment or expression result exceeds @code{$ZPRECISION}.
5486:
5487: @item @code{ZNOVAL} - @emph{function returns no value}
5488: Raised when a function does not return a value. Extrinsic functions must @code{QUIT} with a value.
5489:
5490: @item @code{ZTYPEMISMATCH} - @emph{type mismatch}
5491: Raised when a type mismatch occurs.
5492:
5493: @item @code{ZMEMOV} - @emph{out of memory}
5494: Raised when FreeM runs out of heap memory.
5495:
5496: @item @code{ZNAMERES} - @emph{error in name resolution}
5497: Raised when an attempted name resolution fails.
5498:
5499: @item @code{ZSCKCREAT} - @emph{error creating socket}
5500: Raised when an error occurs creating a socket for network I/O.
5501:
5502: @item @code{ZSCKIFAM} - @emph{invalid address family (must be IPV4 or IPV6)}
5503: Raised when the address family specified in an @code{OPEN} command for a socket I/O channel is not IPV4 or IPV6.
5504:
5505: @item @code{ZSCKITYP} - @emph{invalid connection type (must be TCP or UDP)}
5506: Raised when the connection type specified in an @code{OPEN} command for a socket I/O channel is not @code{TCP} or @code{UDP}.
5507:
5508: @item @code{ZSCKIPRT} - @emph{invalid port number}
5509: 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.
5510:
5511: @item @code{ZSCKCERR} - @emph{connection error}
5512: Raised when an error occurs on a @code{USE <channel>:/CONNECT} command.
5513:
5514: @item @code{ZSCKAERR} - @emph{USE action invalid for connection type (possibly CONNECT on UDP socket?)}
5515: Raised when an attempt is made to @code{USE <channel>:/CONNECT} on a UDP socket I/O channel. The UDP protocol is connectionless.
5516:
5517: @item @code{ZSCKACON} - @emph{attempted to CONNECT an already-connected socket}
5518: Raised when an attempt is made to @code{USE <channel>:/CONNECT} on a TCP socket I/O channel that is already connected.
5519:
5520: @item @code{ZSCKNCON} - @emph{attempted to READ from a disconnected TCP socket}
5521: Raised when an attempt is made to @code{READ} a TCP socket that has not yet been connected.
5522:
5523: @item @code{ZSCKEOPT} - @emph{error setting socket options}
5524: Raised when an error is encountered while setting socket options.
5525:
5526: @item @code{ZSCKERCV} - @emph{error in READ from socket}
5527: Raised when an error occurs in a socket I/O channel @code{READ}.
5528:
5529: @item @code{ZSCKESND} - @emph{error in WRITE to socket}
5530: Raised when an error occurs while attempting to @code{WRITE} to a socket I/O channel.
5531:
5532: @item @code{ZNORPI} - @emph{^$ZRPI only supported on Raspberry Pi hardware}
5533: Raised when an attempt is made to use the @code{^$ZRPI} structured system variable on a platform other than the Raspberry Pi single-board computer.
5534:
5535: @item @code{ZCREDEF} - @emph{cannot redefine CONST}
5536: Raised when attempts are made to redefine a @code{CONST} after its initial definition.
5537:
5538: @item @code{ZCMODIFY} - @emph{cannot modify CONST}
5539: Raised when attempts are made to change the value of a @code{CONST}.
5540:
5541: @item @code{ZFILEXWR} - @emph{cannot open existing file for WRITE}
5542: Raised when an attempt is made to open an existing file in write (but not append) mode.
5543:
5544: @item @code{INEWMULT} - @emph{initializing NEW with multiple setarguments not supported}
5545: Raised when you attempt to use multiple setarguments with initializing @code{NEW}, e.g. @code{NEW X=2,Y=3}.
5546:
5547: @item @code{ZECODEINV} - @emph{invalid value for $ECODE}
5548: Raised when attempts are made to set @code{$ECODE} to an invalid error code value. Obsolete and replaced by standard error code @code{M101}.
5549:
5550: @item @code{ZASSERT} - @emph{programmer assertion failed}
5551: Raised when an @code{ASSERT} expression's result is not true.
5552:
5553: @item @code{ZUSERERR} - @emph{user-defined error}
5554: Raised when program code calls @code{THROW} with an error code argument for which the first character is @code{U}, or when @code{$ECODE} is set to an error code for which the first character is @code{U}.
5555:
5556: Custom error messages for @code{ZUSERERR} may be set in @code{^$JOB($JOB,"USER_ERRORS",<user_error_code>)}, where @code{<user_error_code>} represents the custom error code.
5557:
5558: For example:
5559:
5560: @example
1.22 snw 5561: DEFAULT.USER> S ^$JOB($JOB,"USER_ERRORS","UBLACKHOLE")="black hole encountered"
1.1 snw 5562:
5563:
1.22 snw 5564: DEFAULT.USER> THROW UBLACKHOLE
1.1 snw 5565:
5566:
5567: >> Error UBLACKHOLE: black hole encountered in SYSTEM::^%SYSINIT [$STACK = 0]
5568: >> THROW UBLACKHOLE
5569: ^
5570: @end example
5571:
5572: @item @code{ZSYNTERR} - @emph{syntax error}
5573: Raised when a syntax error without a more specific error code is encountered.
5574:
5575: @item @code{ZCTRLB} - @emph{break}
5576: Pseudo-error used by the FreeM debugger. Not visibly raised in normal program operation.
5577:
5578: @item @code{ZASYNC} - @emph{asynchronous interruption}
5579: Pseudo-error used by the FreeM asynchronous events subsystem. Not visibly raised in normal program operation.
5580:
5581: @item @code{M1} - @emph{naked indicator undefined}
5582: Raised when an attempt is made to use a naked reference before the naked indicator is set.
5583:
5584: @item @code{M2} - @emph{invalid combination with $FNUMBER code atom}
5585:
5586:
5587: @item @code{M3} - @emph{$RANDOM seed less than 1}
5588:
5589:
5590: @item @code{M4} - @emph{no true condition in $SELECT}
5591:
5592:
5593: @item @code{M5} - @emph{line reference less than zero}
5594:
5595:
5596: @item @code{M6} - @emph{undefined local variable}
5597:
5598:
5599: @item @code{M7} - @emph{undefined global variable}
5600:
5601:
5602: @item @code{M8} - @emph{undefined intrinsic special variable}
5603:
5604:
5605: @item @code{M9} - @emph{divide by zero}
5606:
5607:
5608: @item @code{M10} - @emph{invalid pattern match range}
5609:
5610:
5611: @item @code{M11} - @emph{no parameters passed}
5612:
5613:
5614: @item @code{M12} - @emph{invalid line reference (negative offset)}
5615:
5616:
5617: @item @code{M13} - @emph{invalid line reference (line not found)}
5618:
5619:
5620: @item @code{M14} - @emph{line level not 1}
5621:
5622:
5623: @item @code{M15} - @emph{undefined index variable}
5624:
5625:
5626: @item @code{M16} - @emph{argumented QUIT not allowed}
5627:
5628:
5629: @item @code{M17} - @emph{argumented QUIT required}
5630:
5631:
5632: @item @code{M18} - @emph{fixed length READ not greater than zero}
5633:
5634:
5635: @item @code{M19} - @emph{cannot copy a tree or subtree onto itself}
5636:
5637:
5638: @item @code{M20} - @emph{line must have a formal parameter list}
5639:
5640:
5641: @item @code{M21} - @emph{algorithm specification invalid}
5642:
5643:
5644: @item @code{M22} - @emph{SET or KILL to ^$GLOBAL when data in global}
5645:
5646:
5647: @item @code{M23} - @emph{SET or KILL to ^$JOB for non-existent job number}
5648:
5649:
5650: @item @code{M24} - @emph{change to collation algorithm while subscripted local variables defined}
5651:
5652:
5653: @item @code{M26} - @emph{non-existent environment}
5654:
5655:
5656: @item @code{M27} - @emph{attempt to rollback a transaction that is not restartable}
5657:
5658:
5659: @item @code{M28} - @emph{mathematical function, parameter out of range}
5660:
5661:
5662: @item @code{M29} - @emph{SET or KILL on structured system variable not allowed by implementation}
5663:
5664:
5665: @item @code{M30} - @emph{reference to global variable with different collating sequence within a collating algorithm}
5666:
5667:
5668: @item @code{M31} - @emph{control mnemonic used for device without a mnemonic space selected}
5669:
5670:
5671: @item @code{M32} - @emph{control mnemonic used in user-defined mnemonic space which has no associated line}
5672:
5673:
5674: @item @code{M33} - @emph{SET or KILL to ^$ROUTINE when routine exists}
5675:
5676:
5677: @item @code{M35} - @emph{device does not support mnemonic space}
5678:
5679:
5680: @item @code{M36} - @emph{incompatible mnemonic spaces}
5681:
5682:
5683: @item @code{M37} - @emph{READ from device identified by empty string}
5684:
5685:
5686: @item @code{M38} - @emph{invalid structured system variable subscript}
5687:
5688:
5689: @item @code{M39} - @emph{invalid $NAME argument}
5690:
5691:
5692: @item @code{M40} - @emph{call-by-reference in JOB actual parameter}
5693:
5694:
5695: @item @code{M41} - @emph{invalid LOCK argument within a transaction}
5696:
5697:
5698: @item @code{M42} - @emph{invalid QUIT within a transaction}
5699:
5700:
5701: @item @code{M43} - @emph{invalid range value ($X, $Y}
5702:
5703:
5704: @item @code{M44} - @emph{invalid command outside of a transaction}
5705:
5706:
5707: @item @code{M45} - @emph{invalid GOTO reference}
5708:
5709:
5710: @item @code{M56} - @emph{identifier exceeds maximum length}
5711:
5712:
5713: @item @code{M57} - @emph{more than one defining occurrence of label in routine}
5714:
5715:
5716: @item @code{M58} - @emph{too few formal parameters}
5717:
5718:
5719: @item @code{M60} - @emph{illegal attempt to use an undefined SSVN}
5720:
5721:
5722: @item @code{M101} - @emph{invalid value for $ECODE}
5723:
5724:
5725: @item @code{M102} - @emph{synchronous and asynchronous event processing cannot be simultaneously enabled for the same event class}
5726:
5727:
5728: @item @code{M103} - @emph{invalid event identifier}
5729:
5730:
5731: @item @code{M104} - @emph{ETRIGGER event identifier for IPC event class does not match job process identifier}
5732:
5733:
5734: @end table
5735:
1.35 snw 5736:
1.1 snw 5737: @node System Configuration
5738: @chapter System Configuration
5739: @cindex configuration, system
5740:
5741: @section Installing FreeM
5742: @cindex installation
5743:
1.35 snw 5744: @subsection Installation Methods
1.1 snw 5745:
1.35 snw 5746: FreeM allows the following installation methods:
1.1 snw 5747: @table @asis
1.35 snw 5748: @item Binary Repository
5749: 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 5750:
1.35 snw 5751: If available, this is the simplest method of installing FreeM.
5752: @item Binary Packages
5753: 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.
5754:
5755: See @emph{https://freem.coherent-logic.com/binaries.cfm} for downloads and instructions.
5756: @item Source Archive
5757: 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:
5758:
5759: @example
5760: $ gunzip freem-@emph{<version>}.tar.gz
5761: $ tar xf freem-@emph{<version>}.tar
5762: $ cd freem
5763: $ ./configure # see the Build Configuration section for optional flags
5764: $ make
5765: $ sudo make install
5766: @end example
1.1 snw 5767:
1.35 snw 5768: Once this process has been completed, you may proceed to @emph{Initial Configuration}.
1.1 snw 5769:
1.35 snw 5770: Installation from source archive is the most challenging but flexible supported option for advanced users.
5771: @item CVS Repository
5772: If you wish to try the bleeding-edge development version of FreeM, you may do so by following these steps:
1.1 snw 5773:
1.35 snw 5774: @verbatim
5775: $ cvs -d :pserver:anonymous@cvs.coherent-logic.com:/home/cvsroot co freem
5776: $ cd freem
5777: $ ./autogen.sh
5778: $ ./configure # see the Build Configuration section for optional flags
1.1 snw 5779: $ make
5780: $ sudo make install
1.35 snw 5781: @end verbatim
5782:
5783: Once this process has been completed, you may proceed to @emph{Initial Configuration}.
5784:
5785: 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.
5786:
5787: See the @emph{Contributor Guide} on the @emph{FreeM Wiki} for more information.
5788: @end table
5789: @subsection Build Configuration
5790: @cindex build configuration
5791:
5792: 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:
5793:
5794: @table @asis
1.1 snw 5795:
1.35 snw 5796: @item @code{--enable-mwapi} (EXPERIMENTAL)
5797: 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 5798:
5799: Please consult your operating system's documentation for the correct commands to install the required libraries.
5800:
5801: @emph{Example}
5802:
5803: @example
1.35 snw 5804: $ ./configure --enable-mwapi
1.1 snw 5805: $ make
5806: $ sudo make install
5807: @end example
5808:
1.35 snw 5809: @end table
1.1 snw 5810:
1.35 snw 5811: @subsection Initial Configuration
5812: Once FreeM is installed, you will need to configure it:
1.1 snw 5813:
1.35 snw 5814: @enumerate
5815: @item Create a user and group, each named @emph{freem}, under which FreeM will run
5816: @item Add any user accounts that will need to run FreeM to the @emph{freem} group
5817: @item Have all users added in step 2 sign out and sign in for the new group membership to take effect
5818: @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
5819: @item Run @code{fmadm start environment} with superuser privileges to start the @code{DEFAULT} environment
5820: @item Make sure the environment is ready by running @code{fmadm status environment} with superuser privileges
5821: @end enumerate
5822:
5823: @subsubsection Creating Additional Environments
5824: To create additional environments, do the following steps:
5825:
5826: @enumerate
5827: @item Create a new user and group for the environment @emph{(optional)}
5828: @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)}
5829: @item Run @code{fmadm start environment -e=@emph{<environment>}} to start the environment
5830: @item Run @code{fmadm status environment} to make sure the environment is healthy
5831: @end enumerate
1.1 snw 5832:
1.35 snw 5833: @subsubsection Additional Customization
1.1 snw 5834:
1.35 snw 5835: See the FreeM @emph{environment catalog} at @code{@emph{$PREFIX}/etc/freem/env.conf}, and the @emph{fmadm}(1) @code{man} page for more information.
1.1 snw 5836:
1.35 snw 5837: @emph{$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 5838:
5839: @node Accessing FreeM from C Programs
5840: @chapter Accessing FreeM from C Programs
5841:
5842: 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.
5843:
5844: 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.
5845:
5846: 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.
5847:
5848: 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}.
5849:
5850: @section freem_ref_t Data Structure
5851: @cindex libfreem, data structures: freem_ref_t
5852:
5853: 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.
5854:
5855: The data structure, defined in @file{freem.h}, looks like this:
5856:
5857: @verbatim
5858: typedef struct freem_ref_t {
5859:
5860: /*
5861: * The 'reftype' field can be one of:
5862: *
5863: * MREF_RT_LOCAL
5864: * MREF_RT_GLOBAL
5865: * MREF_RT_SSV
5866: */
5867: short reftype;
5868:
5869: /*
5870: * The 'name' field is the name of the local variable,
5871: * global variable, or SSVN (without ^ or ^$).
5872: */
5873: char name[256];
5874:
5875: /*
5876: * Returned data goes in a string, so you've got to figure out the
5877: * whole M canonical number thing yourself. Good luck. :-)
5878: */
5879: char value[STRLEN];
5880:
5881: short status;
5882:
5883: unsigned int subscript_count;
5884: char subscripts[255][256];
5885:
5886: } freem_ref_t;
5887: @end verbatim
5888:
5889: @emph{freem_ref_t Members}
5890:
5891: @table @asis
5892: @cindex libfreem, freem_ref_t.reftype
5893: @item @option{reftype}
5894: The @option{reftype} member determines whether we are operating on a local variable, a global variable, or a structured system variable. It may be set to any of following constants: @code{MREF_RT_LOCAL}, @code{MREF_RT_GLOBAL}, or @code{MREF_RT_SSV}.
5895:
5896: @cindex libfreem, freem_ref_t.name
5897: @item @option{name}
5898: The @option{name} member contains the name of the global, local, or SSVN to be accessed. You @emph{must not} include leading characters, such as @code{^} or @code{^$}.
5899:
5900: @cindex libfreem, freem_ref_t.value
5901: @item @option{value}
5902: This member contains the value read from or the value to be written to the global, local, or SSVN.
5903:
5904: @cindex libfreem, freem_ref_t.status
5905: @item @option{status}
5906: This member gives us various API status values after the API call returns. In general, this value is also returned by each API function.
5907:
5908: @cindex libfreem, freem_ref_t.subscript_count
5909: @item @option{subscript_count}
5910: 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.
5911:
5912: @cindex libfreem, freem_ref_t.subscripts
5913: @item @option{subscripts}
5914: A two-dimensional array containing the subscripts to which we are referring in this API call.
5915:
5916: @end table
5917:
5918: @section freem_ent_t Data Structure
5919: @cindex libfreem, data structures: freem_ent_t
5920:
5921: 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()}).
5922:
5923: The data structure, defined in @file{freem.h}, looks like this:
5924:
5925: @verbatim
5926: typedef struct freem_ent_t {
5927:
5928: /* name of function or procedure entry point */
5929: char name[256];
5930:
5931: /* return value */
5932: char value[STRLEN];
5933:
5934: /* value of ierr on return */
5935: short status;
5936:
5937: /* argument count and array */
5938: unsigned int argument_count;
5939: char arguments[255][256];
5940:
5941: } freem_ent_t;
5942: @end verbatim
5943:
5944: @emph{freem_ent_t Members}
5945:
5946: @table @asis
5947:
5948: @item @option{name}
5949: @cindex libfreem, freem_ent_t.name
5950: The @option{name} member contains the name of the extrinsic function or procedure to be called.
5951:
5952: @cindex libfreem, freem_ent_t.value
5953: @item @option{value}
5954: This member contains the value returned by the function called. Not used by @code{freem_procedure()}.
5955:
5956: @cindex libfreem, freem_ent_t.status
5957: @item @option{status}
5958: 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}.
5959:
5960: @cindex libfreem, freem_ent_t.argument_count
5961: @item @option{argument_count}
5962: 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.
5963:
5964: @cindex libfreem, freem_ent_t.arguments
5965: @item @option{arguments}
5966: A two-dimensional array containing the arguments to be passed into the extrinsic function or procedure being called.
5967:
5968: @end table
5969:
5970: @section freem_init()
5971: @cindex libfreem, freem_init()
5972:
5973: Initializes @code{libfreem} in preparation for calling other APIs.
5974:
5975: @emph{Synopsis}
5976:
5977: @code{pid_t freem_init(char *environment_name, char *namespace_name);}
5978:
5979: @emph{Parameters}
5980:
5981: @table @asis
5982: @item @code{environment_name}
5983: Specifies the environment to use.
5984: @item @code{namespace_name}
5985: Specifies the namespace to use.
5986: @end table
5987:
5988: @emph{Return Values}
5989:
5990: Returns the process ID of the @code{libfreem} process on success, or @code{-1} on failure.
5991:
5992: @emph{Example}
5993:
5994: This example prompts the user to enter a FreeM namespace and then attempts to initialize @code{libfreem} to use the selected namespace.
5995:
5996: @verbatim
5997: #include <stdio.h>
5998: #include <string.h>
5999: #include <freem.h>
6000:
6001: int main(int argc, char **argv, char **envp)
6002: {
6003: char namespace[256];
6004:
6005: /* get the namespace name to use */
6006: printf("Enter FreeM namespace to use: ");
6007: fgets(namespace, 255, stdin);
6008:
6009: /* remove the trailing newline */
6010: namespace[strcspn(buffer, "\n")] = '\0';
6011:
6012: /* initialize libfreem using the provided namespace */
6013: if(freem_init("DEFAULT", namespace) == TRUE) {
6014: printf("\nSuccess\n");
6015: }
6016: else {
6017: printf("\nFailure\n");
6018: }
6019:
6020: return 0;
6021: }
6022: @end verbatim
6023:
6024: @section freem_version()
6025: @cindex libfreem, freem_version()
6026:
6027: Returns the version of FreeM in use.
6028:
6029: @emph{Synopsis}
6030:
6031: @code{short freem_version(char *result);}
6032:
6033: @emph{Parameters}
6034:
6035: @table @asis
6036: @item @code{result}
6037: 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.
6038: @end table
6039:
6040: @emph{Return Value}
6041:
6042: Returns @code{0}.
6043:
6044: @emph{Example}
6045:
6046: This example will display the FreeM version on standard output.
6047:
6048: @verbatim
6049: #include <stdio.h>
6050: #include <string.h>
6051: #include <freem.h>
6052:
6053: int main(int argc, char **argv, char **envp)
6054: {
6055: char version[20] = {0};
6056:
6057: freem_init(``USER'');
6058: freem_version(version);
6059:
6060: printf(``FreeM version: %s\n'', version);
6061:
6062: }
6063: @end verbatim
6064:
6065: @section freem_set()
6066: @cindex libfreem, freem_set()
6067:
6068: Sets a FreeM local node, global node, or writable SSVN node.
6069:
6070: @emph{Synopsis}
6071:
6072: @code{short freem_set(freem_ref_t *ref);}
6073:
6074: @emph{Parameters}
6075:
6076: @table @asis
6077: @item @code{freem_ref_t}
6078: This parameter is a pointer to a @code{freem_ref_t} struct. The caller must allocate the memory for this struct.
6079: @end table
6080:
6081: @emph{Return Value}
6082:
6083: Returns @code{OK} on success, or one of the other error values defined in @code{merr.h}.
6084:
6085: @emph{Example}
6086:
6087: This example sets the value @code{blue} into global node @code{^car("color")}.
6088:
6089: @verbatim
6090: #include <stdio.h>
6091: #include <string.h>
6092: #include <freem.h>
6093:
6094: int main(int argc, char **argv, char **envp)
6095: {
6096: freem_ref_t ref;
6097:
6098: /* we're setting a global */
6099: ref.reftype = MREF_RT_GLOBAL;
6100:
6101: /* access global "car" */
6102: strcpy(ref.name, "car");
6103:
6104: /* set up the subscripts */
6105: ref.subscript_count = 1;
6106: strcpy(ref.subscripts[0], "color");
6107:
6108:
6109: /* use the USER namespace */
6110: freem_init("USER");
6111:
6112: /* write the data out */
6113: freem_set(&ref);
6114:
6115: }
6116: @end verbatim
6117:
6118: @section freem_get()
6119: @cindex libfreem, freem_get()
6120:
6121: Retrieves a FreeM local node, global node, or writable SSVN node.
6122:
6123: @emph{Synopsis}
6124:
6125: @code{short freem_get(freem_ref_t *ref);}
6126:
6127: @emph{Parameters}
6128:
6129: @table @asis
6130: @item @code{freem_ref_t}
6131: This parameter is a pointer to a @code{freem_ref_t} struct. The caller must allocate the memory for this struct.
6132: @end table
6133:
6134: @emph{Return Value}
6135:
6136: Returns @code{OK} on success, or one of the other error values defined in @code{merr.h}.
6137:
6138: @emph{Example}
6139:
6140: This example retrieves the character set of the current process.
6141:
6142: @verbatim
6143: #include <stdio.h>
6144: #include <sys/types.h>
6145: #include <unistd.h>
6146: #include <string.h>
6147: #include <freem.h>
6148:
6149: int main(int argc, char **argv, char)
6150: {
6151: pid_t pid;
6152: freem_ref_t ref;
6153:
6154: /* get the PID of this process */
6155: pid = getpid();
6156:
6157: /* we want to access an SSVN */
6158: ref.reftype = MREF_RT_SSV;
6159:
6160: /* set up the name and subscripts */
6161: strcpy(ref.name, "JOB");
6162:
6163: ref.subscript_count = 2;
6164: sprintf(ref.subscripts[0], "%d", pid);
6165: strcpy(ref.subscripts[1], "CHARACTER");
6166:
6167: /* initialize libfreem, using the USER namespace */
6168: freem_init("USER");
6169:
6170: /* call libfreem API */
6171: freem_get(&ref);
6172:
6173: /* output the character set info */
6174: printf("PID %d character set is '%s'\n", pid, ref.value);
6175: }
6176: @end verbatim
6177:
6178: @section freem_kill()
6179: @cindex libfreem, freem_kill()
6180:
6181: Deletes a FreeM local node, global node, or killable SSVN node, as well as all of its children.
6182:
6183: @emph{short freem_kill(freem_ref_t *ref);}
6184:
6185: @emph{Parameters}
6186:
6187: @table @asis
6188: @item @code{freem_ref_t}
6189: This parameter is a pointer to a @code{freem_ref_t} struct. The caller must allocate the memory for this struct.
6190: @end table
6191:
6192: @emph{Return Value}
6193:
6194: Returns @code{OK} on success, or one of the other error values defined in @code{merr.h}.
6195:
6196: @emph{Example}
6197:
6198: @verbatim
6199: #include <stdio.h>
6200: #include <string.h>
6201: #include <freem.h>
6202:
6203: int main(int argc, char **argv, char **envp)
6204: {
6205: freem_ref_t ref;
6206:
6207: /* we're killing a global node */
6208: ref.reftype = MREF_RT_GLOBAL;
6209:
6210: /* access global "car" */
6211: strcpy(ref.name, "car");
6212:
6213: /* set up the subscripts */
6214: ref.subscript_count = 0;
6215:
6216: /* use the USER namespace */
6217: freem_init("USER");
6218:
6219: /* kill the global and all its descendant subscripts */
6220: freem_kill(&ref);
6221: }
6222: @end verbatim
6223:
6224: @section freem_data()
6225: @cindex libfreem, freem_data()
6226:
6227: @section freem_order()
6228: @cindex libfreem, freem_order()
6229:
6230: @section freem_query()
6231: @cindex libfreem, freem_query()
6232:
6233: @section freem_lock()
6234: @cindex libfreem, freem_lock()
6235:
6236: @section freem_unlock()
6237: @cindex libfreem, freem_unlock()
6238:
6239: @section freem_tstart()
6240: @cindex libfreem, freem_tstart()
6241:
6242: @section freem_trestart()
6243: @cindex libfreem, freem_trestart()
6244:
6245: @section freem_trollback()
6246: @cindex libfreem, freem_trollback()
6247:
6248: @section freem_tlevel()
6249: @cindex libfreem, freem_tlevel()
6250:
6251: @section freem_tcommit()
6252: @cindex libfreem, freem_tcommit()
6253:
6254: @section freem_function()
6255: @cindex libfreem, freem_function()
6256:
6257: @section freem_procedure()
6258: @cindex libfreem, freem_procedure()
6259:
6260: @node FreeM Administrator
6261: @appendix FreeM Administrator
6262: @cindex utilities, system management
6263: @cindex utilities, fmadm
6264: @cindex fmadm
6265:
6266: The @code{fmadm} utility is the preferred method of managing a FreeM installation, and will eventually replace all of the existing utilities.
6267: Unlike the existing, legacy utilities, @code{fmadm} presents a consistent, simple interface for all FreeM management tasks, and is namespace-aware.
6268: This appendix will document each @code{fmadm} facility as it is implemented, until all of the legacy utilities have been replaced.
6269:
6270: The @code{fmadm} utility's functions all follow the below, consistent syntax:
6271:
6272: @example
6273: usage: fmadm <action> <object> <namespace> [OPTIONS]
6274: @end example
6275:
6276: The @emph{action} keyword can be one of the following:
6277:
6278: @table @emph
6279:
6280: @item list
6281: Lists instances of @emph{object}
6282:
6283: @item examine
6284: Examines a single instance of @emph{object}
6285:
6286: @item verify
6287: Verifies the integrity of @emph{object}
6288:
6289: @item compact
6290: Compacts @emph{object}
6291:
6292: @item repair
6293: Repairs integrity problems in @emph{object}
6294:
6295: @item create
6296: Creates an instance of @emph{object}
6297:
6298: @item remove
6299: Removes an instance of @emph{object}
6300:
6301: @item import
6302: Imports an @emph{object}
6303:
6304: @item export
6305: Exports an @emph{object}
6306:
6307: @item backup
6308: Creates a backup of @emph{object}
6309:
6310: @item restore
6311: Restores a backup of @emph{object}
6312:
6313: @item migrate
6314: Migrates an instance of @emph{object} from an older FreeM version to the current version
6315:
6316: @item edit
6317: Edits an instance of @emph{object}
6318:
6319: @end table
6320:
6321: The @emph{object} keyword can be one of the following:
6322:
6323: @table @emph
6324:
6325: @item lock
6326: The FreeM @code{LOCK} table.
6327:
6328: Supported actions are @code{list} and @code{remove}.
6329:
6330: @item journal
6331: FreeM after-image journaling.
6332:
6333: Supported actions are @code{examine} and @code{restore}.
6334:
6335: The @code{examine} action will dump the after-image journal entries for the selected namespace in human-readable format.
6336:
6337: The @code{restore} action will play after-image journals forward for the selected namespace.
6338:
6339: @item namespace
6340: FreeM namespaces (collections of M routines and globals).
6341:
6342: No actions yet implemented.
6343:
6344: @item global
6345: The data files representing each FreeM @emph{global}.
6346:
6347: Supported actions are @code{list}, @code{examine}, @code{remove}, and @code{verify}.
6348:
6349: @item routine
6350: An M routine, stored as a @code{.m} file.
6351:
6352: Supported actions are @code{list}, @code{examine}, @code{remove}, @code{import}, @code{export}, @code{backup}, and @code{edit}.
6353:
6354: @item job
6355: A UNIX process representing an instance of the FreeM runtime.
6356:
6357: Supported actions are @code{list} and @code{examine}.
6358:
6359: @end table
6360:
6361:
6362: @node FreeM Legacy Utilities
6363: @appendix FreeM Legacy Utilities
6364: @cindex utilities, legacy
6365:
6366: @section Global Compactor (gcompact)
6367: @cindex utilities, legacy, gcompact
6368:
6369: Compacts the specified global in place.
6370:
6371: @emph{Syntax}
6372:
6373: @example
6374: gcompact @emph{/path/to/global/file}
6375: @end example
6376:
6377: @section Block Examiner (gfix)
6378: @cindex utilities, gfix
6379:
6380: The @emph{gfix} interactive utility program permits navigation of the B-tree structure of the specified global a block at a time.
6381:
6382: @emph{Syntax}
6383:
6384: @example
6385: gfix @emph{</path/to/global/file>}
6386: @end example
6387:
6388: @section Global Repair Tool (grestore)
6389: @cindex utilities, legacy, grestore
6390:
6391: This utility will fix problems with the specified global.
6392:
6393: @emph{Syntax}
6394:
6395: @example
6396: grestore @emph{</path/to/global/file>}
6397: @end example
6398:
6399: @node FreeM VIEW Commands and Functions
6400: @appendix FreeM VIEW Commands and Functions
6401:
6402: @section VIEW 16: Total Count of Error Messages/View Single Error Message
6403: @cindex VIEW commands/functions, 16, total count of error messages/view single error message
6404:
6405: Unknown semantics
6406:
6407: @section VIEW 17: Intrinsic Z-Commands
6408: @cindex VIEW commands/functions, 17, intrinsic Z-commands
6409:
6410: 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.
6411:
6412: @section VIEW 18: Intrinsic Z-Functions
6413: @cindex VIEW commands/functions, 18, intrinsic Z-functions
6414:
6415: 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.
6416:
6417: @section VIEW 19: Intrinsic Special Variables
6418: @cindex VIEW commands/functions, 19, intrinsic special variables
6419:
6420: Allows the user to retrieve or specify which special variables are implemented internally.
6421:
6422: @section VIEW 20: Break Service Code
6423: @cindex VIEW commands/functions, 20, break service code
6424:
6425: Allows the user to view or specify the code that will be run when a @code{BREAK} is encountered.
6426:
6427: @section VIEW 21: View Size of Last Global
6428: @cindex VIEW commands/functions, 21, view size of last global
6429:
6430: Allows the user to view the size of the last referenced global.
6431:
6432: @section VIEW 22: Count VIEW 22 Aliases
6433: @cindex VIEW commands/functions, 22, count VIEW 22 aliases
6434:
6435: Retrieves the number of VIEW 22 aliases in effect.
6436:
6437: @section VIEW 23: View Contents of Input Buffer
6438: @cindex VIEW commands/functions, 23, input buffer contents
6439:
6440: Retrieves the contents of the I/O input buffer.
6441:
6442: @section VIEW 24: Maximum Number of Screen Rows
6443: @cindex VIEW commands/functions, 24, maximum number of screen rows
6444:
6445: Retrieves the maximum number of screen rows supported in the current FreeM build.
6446:
6447: @section VIEW 25: Maximum Number of Screen Columns
6448: @cindex VIEW commands/functions, 25, maximum number of screen columns
6449:
6450: Retrieves the maximum number of screen columns supported in the current FreeM build.
6451:
6452: @section VIEW 26: DO/FOR/XECUTE Stack Pointer
6453: @cindex VIEW commands/functions, 26, DO/FOR/XECUTE stack pointer
6454:
6455: Retrieves the @code{DO}, @code{FOR}, and @code{XECUTE} stack pointer.
6456:
6457: @section VIEW 27: DO/FOR/XECUTE Stack Pointer (On Error)
6458: @cindex VIEW commands/functions, 27, DO/FOR/XECUTE stack pointer, on error
6459:
6460: Retrieves the @code{DO}, @code{FOR}, and @code{XECUTE} stack pointer (on error).
6461:
6462: @section VIEW 29: Copy Symbol Table
6463: @cindex VIEW commands/functions, 29, copy symbol table
6464:
6465: Copies the symbol table? We aren't currently aware of what this means.
6466:
6467: @section VIEW 30: Inspect Arguments
6468: @cindex VIEW commands/functions, 30, inspect arguments
6469:
6470: Retrieves the arguments passed to the @code{freem} executable.
6471:
6472: @section VIEW 31: Count Environment Variables
6473: @cindex VIEW commands/functions, 31, count environment variables
6474:
6475: Allows the user to inspect the number of variables in the process environment table.
6476:
6477: @emph{Syntax}
6478:
6479: @example
6480: WRITE $VIEW(31),!
6481: @end example
6482:
6483: @node Implementation Limits
6484: @appendix Implementation Limits
6485:
6486: @cindex limitations, memory
6487: @cindex maximum size, routine
6488: @cindex maximum size, global
6489: @cindex maximum size, string
6490:
6491: @node US-ASCII Character Set
6492: @appendix US-ASCII Character Set
6493:
6494: @multitable {Code} {Character}
6495: @item Code @tab Character
6496: @item 000 @tab @code{<NUL>}
6497: @item 001 @tab @code{<SOH>}
6498: @item 002 @tab @code{<STX>}
6499: @item 003 @tab @code{<ETX>}
6500: @item 004 @tab @code{<EOT>}
6501: @item 005 @tab @code{<ENQ>}
6502: @item 006 @tab @code{<ACK>}
6503: @item 007 @tab @code{<BEL>}
6504: @item 008 @tab @code{<BS>}
6505: @item 009 @tab @code{<HT>}
6506: @item 010 @tab @code{<LF>}
6507: @item 011 @tab @code{<VT>}
6508: @item 012 @tab @code{<FF>}
6509: @item 013 @tab @code{<CR>}
6510: @item 014 @tab @code{<SO>}
6511: @item 015 @tab @code{<SI>}
6512: @item 016 @tab @code{<DLE>}
6513: @item 017 @tab @code{<DC1>}
6514: @item 018 @tab @code{<DC2>}
6515: @item 019 @tab @code{<DC3>}
6516: @item 020 @tab @code{<DC4>}
6517: @item 021 @tab @code{<NAK>}
6518: @item 022 @tab @code{<SYN>}
6519: @item 023 @tab @code{<ETB>}
6520: @item 024 @tab @code{<CAN>}
6521: @item 025 @tab @code{<EM>}
6522: @item 026 @tab @code{<SUB>}
6523: @item 027 @tab @code{<ESC>}
6524: @item 028 @tab @code{<FS>}
6525: @item 029 @tab @code{<GS>}
6526: @item 030 @tab @code{<RS>}
6527: @item 031 @tab @code{<US>}
6528: @item 032 @tab @code{<space>}
6529: @item 033 @tab !
6530: @item 034 @tab ``
6531: @item 035 @tab #
6532:
6533:
6534: @end multitable
6535:
6536: @node FreeM Project Coding Standards
6537: @appendix FreeM Project Coding Standards
6538:
6539: @section Module Headers
6540: @cindex coding standards, module headers
6541:
1.4 snw 6542: Module headers should adhere to the following format (where @code{Dollar} should be replaced with a dollar sign):
1.1 snw 6543:
6544: @verbatim
6545: /*
1.4 snw 6546: * DollarIdDollar
1.1 snw 6547: * Function prototypes, structs, and macros for FreeM
6548: * binding library
6549: *
6550: *
1.28 snw 6551: * Author: Serena Willis <snw@coherent-logic.com>
1.1 snw 6552: * Copyright (C) 1998 MUG Deutschland
1.4 snw 6553: * Copyright (C) <Year> Coherent Logic Development LLC
6554: *
6555: * This file is part of FreeM.
6556: *
6557: * FreeM is free software: you can redistribute it and/or modify
6558: * it under the terms of the GNU Affero Public License as published by
6559: * the Free Software Foundation, either version 3 of the License, or
6560: * (at your option) any later version.
6561: *
6562: * FreeM is distributed in the hope that it will be useful,
6563: * but WITHOUT ANY WARRANTY; without even the implied warranty of
6564: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
6565: * GNU Affero Public License for more details.
6566: *
6567: * You should have received a copy of the GNU Affero Public License
6568: * along with FreeM. If not, see <https://www.gnu.org/licenses/>.
6569: *
6570: * DollarLogDollar
1.1 snw 6571: *
1.4 snw 6572: * SPDX-FileCopyrightText: (C) 2025 Coherent Logic Development LLC
6573: * SPDX-License-Identifier: AGPL-3.0-or-later
1.1 snw 6574: **/
6575: @end verbatim
6576:
6577: @section Variable Naming
6578: @cindex coding standards, variable naming
6579:
6580: 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.
6581:
6582: Constants defined via the C preprocessor should be in all uppercase letters, with words within them likewise delimited by underscores, such as:
6583:
6584: @verbatim
6585: #define MY_USEFUL_CONSTANT 1
6586: @end verbatim
6587:
6588: @section Indentation and General Layout
6589: @cindex coding standards, indentation
6590: @cindex coding standards, layout
6591:
6592: 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.
6593:
6594: This project follows a modified version of what is known as the Stroustrup indentation style.
6595:
6596: @section Brace Placement (Functions)
6597: @cindex coding standards, brace placement, functions
6598:
6599: 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.
6600:
6601: Below is a correct example:
6602:
6603: @verbatim
6604: int main(int argc, char **argv, char **envp)
6605: {
6606:
6607: }
6608: @end verbatim
6609:
6610: @section Brace Placement (if-for-while-do)
6611: @cindex coding standards, brace placement, if-for-while-do
6612:
6613: 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}:
6614:
6615: @verbatim
6616: if (x) {
6617: ...
6618: }
6619: else {
6620: ...
6621: }
6622:
6623: while (1) {
6624: ...
6625: }
6626:
6627: for (i = 1; i < 10; i++) {
6628: ...
6629: }
6630:
6631: do {
6632: ...
6633: } while (x);
6634: @end verbatim
6635:
6636: Single-statement if blocks should be isolated to a single line:
6637:
6638: @verbatim
6639: if (x) stmt();
6640: @end verbatim
6641:
6642: not:
6643:
6644: @verbatim
6645: if (x)
6646: stmt ();
6647: @end verbatim
6648:
6649: 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.
6650:
6651: 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:
6652:
6653: @verbatim
6654: if (x) {
6655: foo();
6656: }
6657: else if (y) {
6658: bar();
6659: }
6660: else {
6661: bas();
6662: }
6663: @end verbatim
6664:
6665: @section Labels and goto
6666: @cindex coding standards, labels
6667: @cindex coding standards, goto
6668:
6669: Labels must begin in column 1, and have two lines of vertical space above and one beneath.
6670:
6671: @section Preprocessor Conditionals
6672: @section coding standards, preprocessor conditionals
6673:
6674: I have struggled with this, but have settled upon the standard practice of keeping them in column 1.
6675:
6676: @section Overall Program Spacing
6677: @cindex coding standards, spacing of programs
6678:
6679: @itemize @bullet
6680: @item
6681: Variable declarations fall immediately beneath the opening curly brace, and should initialize the variable right there whenever initialization is used.
6682:
6683: @item
6684: One line between the last variable declaration and the first line of real code.
6685:
6686: @item
6687: 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.
6688:
6689: @item
6690: 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.
6691: @end itemize
6692:
6693: @section The switch() Statement
6694: @cindex coding standards, switch()
6695:
6696: 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:
6697:
6698: @verbatim
6699: switch(foo) {
6700:
6701: case some_const:
6702: foo();
6703:
6704: break;
6705:
6706: case some_other_const:
6707: bar();
6708:
6709: break;
6710:
6711: default:
6712: exit(1);
6713:
6714: break;
6715: }
6716: @end verbatim
6717:
6718: @section Comments
6719: @cindex coding standards, comments
6720:
6721: We use C-style comments (@code{/* comment */}) exclusively, even on single-line comments. C++ comments (@code{// comment}) are not permitted.
6722:
6723: @node Index
6724: @unnumbered Index
6725:
6726: @printindex cp
6727:
6728: @bye
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