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version 1.15, 2025/04/04 01:18:21	version 1.30, 2025/04/18 22:12:29
Line 4	Line 4
@settitle The FreeM Manual	@settitle The FreeM Manual

@copying	@copying
This manual is for FreeM, (version 0.63.0-rc4), which is a free and open-source implementation of the M programming language.	This manual is for FreeM, (version 0.64.0-rc0), which is a free and open-source implementation of the M programming language.


Copyright @copyright{} 2014-2025 Coherent Logic Development LLC	Copyright @copyright{} 2014-2025 Coherent Logic Development LLC
Line 18 Permission is granted to copy, distribut	Line 18 Permission is granted to copy, distribut

@title The FreeM Manual	@title The FreeM Manual
@subtitle @sc{The Official Manual of FreeM}	@subtitle @sc{The Official Manual of FreeM}
@subtitle Version 0.63.0-rc4	@subtitle Version 0.64.0-rc0
@c@vskip 10pt	@c@vskip 10pt
@c@center @image{freem-logo-sm,,,,.png}	@c@center @image{freem-logo-sm,,,,.png}
@author Serena Willis	@author Serena Willis
Line 43 This is the official manual for the Free	Line 43 This is the official manual for the Free
@menu	@menu
* Introduction:: About the FreeM Project, its history, and its goals.	* Introduction:: About the FreeM Project, its history, and its goals.
* FreeM Invocation:: How to invoke FreeM from the command line.	* FreeM Invocation:: How to invoke FreeM from the command line.
* The FreeM Daemon:: Managing shared resources in the FreeM environment.	* The FreeM Environment Daemon:: Managing shared resources in the FreeM environment.
* The FreeM Direct-Mode Environment:: Executing M programs interactively.	* The FreeM Direct-Mode Environment:: Executing M programs interactively.

* Directives:: Per-Routine Language Directives.	* Directives:: Per-Routine Language Directives.
Line 110 This is the official manual for the Free	Line 110 This is the official manual for the Free
@node Introduction	@node Introduction
@unnumbered Introduction	@unnumbered Introduction


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 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.	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 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.

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{$Y} intrinsic special variables were updated to support arbitrary terminal sizes, and FreeM was once again able to build and run.	When GT.M was open-sourced in late 1999, FreeM and GUMP were essentially abandoned. L.D. Landis, the owner of the original GUMP SourceForge project, and one of FreeM's significant contributors, passed maintenance of FreeM and ownership of its SourceForge project to Serena Willis in 2014. At this point, FreeM would not compile or run on modern Linux systems, so steps were taken to remedy the most pressing issues in the codebase. Limitations on the terminal size (previously hard-coded to 80x25) were lifted, and new @code{$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.
Line 236 Steve Zeck (Code)	Line 235 Steve Zeck (Code)
$ @command{./freem} [@emph{OPTIONS}...] [[-r <entryref>] \| [--routine=<entryref>]]	$ @command{./freem} [@emph{OPTIONS}...] [[-r <entryref>] \| [--routine=<entryref>]]
@end example	@end example

When FreeM loads, it searches the @code{SYSTEM} namespace for the @code{^%SYSINIT} routine, and begins executing it.	When FreeM loads, it searches the @code{SYSTEM} namespace for the @code{%SYSINIT} routine, and begins executing it.

	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.

	@section %SYSINIT Routine

	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}.

When @code{-r} or @code{--routine} are passed on the command line, FreeM will load and run the specified routine instead of @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.	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.

@section Command-Line Options	@section Command-Line Options
	@cindex options, command-line

@table @asis	@table @asis

@item @option{-d}, @option{--daemon}	@item @option{-d}, @option{--daemon}
Starts the FreeM daemon, exactly one of which must be running at all times in order for FreeM interpreter and fmadm processes to function.	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.

@item @option{-e}, @option{--environment}	@item @option{-e}, @option{--environment}
Selects the environment to be used. If no environment is specified, @code{DEFAULT} is used.	Selects the environment to be used. If no environment is specified, @code{DEFAULT} is used.

@item @option{-k}, @option{--nofork}	@item @option{-k}, @option{--nofork}
When used with @option{-d} or @option{--daemon}, causes the FreeM daemon to run instead in the foreground. Useful for debugging.	When used with @option{-d} or @option{--daemon}, causes the FreeM environment daemon to run instead in the foreground. Useful for debugging.

@item @option{-p}, @option{--pidfile}
When used with @option{-d} or @option{--daemon}, sets the file in which the PID of the running daemon is stored.

@item @option{-S}, @option{--shmsize}	@item @option{-S}, @option{--shmsize}
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.	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.
Line 272 Causes your UNIX environment variables t	Line 275 Causes your UNIX environment variables t
Allows your M routines to be used as UNIX filters.	Allows your M routines to be used as UNIX filters.

@item @option{-n @emph{<namespace-name>}}, @option{--namespace=@emph{<namespace-name>}}	@item @option{-n @emph{<namespace-name>}}, @option{--namespace=@emph{<namespace-name>}}
Selects the FreeM namespace to be entered on startup. Must be defined in @file{/etc/freem.conf}.	Selects the FreeM namespace to be entered on startup. Must be defined in @file{/etc/<environment>/freem.conf}.

@item @option{-r @emph{<entryref>}}, @option{--routine=@emph{<entryref>}}	@item @option{-r @emph{<entryref>}}, @option{--routine=@emph{<entryref>}}
Causes @code{<entryref>} to be executed at load, instead of @code{^%SYSINIT}.	Causes @code{<entryref>} to be executed at load, instead of @code{%SYSINIT}.

@item @option{--standard=@emph{<standard>}}	@item @option{--standard=@emph{<standard>}}
Sets the default FreeM dialect to use for new routine buffers.	Sets the default FreeM dialect to use for new routine buffers.
Line 305 Please note that FreeM is not entirely s	Line 308 Please note that FreeM is not entirely s
Displays FreeM version information.	Displays FreeM version information.

@item @option{-x @emph{<mcode>}}, @option{--execute=@emph{<mcode>}}	@item @option{-x @emph{<mcode>}}, @option{--execute=@emph{<mcode>}}
Executes M code @code{<mcode>} at startup instead of the startup routine.	Executes M code @code{<mcode>} at startup.

@end table	@end table

Line 333 You will also need to set the script's p	Line 336 You will also need to set the script's p
$ chmod +x @emph{myscript.m}	$ chmod +x @emph{myscript.m}
@end example	@end example

@node The FreeM Daemon	@node The FreeM Environment Daemon
@chapter The FreeM Daemon	@chapter The FreeM Environment Daemon
@cindex daemon, freem	@cindex daemon, freem

The FreeM 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 daemon does @emph{not} function as a write daemon for global storage.	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.

	One daemon process is required per FreeM environment, and can be started in the following ways, in order of preference:

One daemon process is required per FreeM environment, and can be started as follows:	@example
	$ sudo fmadm start environment [-e=<environment-name>]
	@end example

@example	@example
$ freem --daemon [--nofork] [--environment=<environment-name>] [--user=<username>] \	$ freem --daemon [--nofork] [--environment=<environment-name>] [--shmsize=<bytes>]
[--group=<group-name>] [--pidfile=<pid-file>] [--shmsize=<bytes>]
@end example	@end example

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.	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.

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.	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.

The @option{--user} and @option{--group} options are only valid when the FreeM daemon is started by the superuser, and will cause the daemon to reduce its runtime privileges to those of the specified user and group, and run as that user and/or group. We recommend creating a @code{freem} user and group and running the FreeM daemon with @code{--user=freem --group=freem}.

The @option{--pidfile} option specifies the file in which the FreeM daemon will store its own PID. If running as the superuser, the FreeM daemon will store the PID file in @code{/var/run/freem.pid}. Otherwise, the PID file will be stored as @code{.freem.pid} in the home directory of the user account which owns the FreeM daemon process.

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.	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.

Attempting to start a FreeM interpreter process without a daemon running with the same environment name will result in an error.	Attempting to start a FreeM interpreter process without a daemon running with the same environment name will result in an error.
Line 369 Attempting to start a FreeM interpreter	Line 371 Attempting to start a FreeM interpreter
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>}}:	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>}}:

@example	@example
Coherent Logic Development FreeM version 0.63.0-rc4 (x86_64-pc-linux-gnu)	Coherent Logic Development FreeM version 0.64.0-rc0 (x86_64-pc-linux-gnu)
Copyright (C) 2014, 2020, 2021 Coherent Logic Development LLC	Copyright (C) 2014, 2020, 2021 Coherent Logic Development LLC


USER>	USER>
@end example	@end example

The prompt (@code{USER>}) indicates the currently-active namespace. If any uncommitted direct-mode transactions have been started, the prompt will change to reflect the current value of @code{@ref{$TLEVEL}}:	The prompt (@code{DEFAULT.USER>}) displays the current environment and namespace, @code{DEFAULT} and @code{USER}, respsectively. If any uncommitted direct-mode transactions have been started, the prompt will change to reflect the current value of @code{@ref{$TLEVEL}}:

@example	@example
TL1:USER>	TL1:DEFAULT.USER>
@end example	@end example

In the above example, @code{TL1} indicates that @code{@ref{$TLEVEL}} is currently @emph{1}.	In the above example, @code{TL1} indicates that @code{@ref{$TLEVEL}} is currently @emph{1}.
Line 397 Accesses FreeM online help. Requires GNU	Line 399 Accesses FreeM online help. Requires GNU
Writes a list of @emph{event classes} and their @code{ABLOCK} counts:	Writes a list of @emph{event classes} and their @code{ABLOCK} counts:

@example	@example
USER> events	DEFAULT.USER> events

Event Class Processing Mode ABLOCK Count	Event Class Processing Mode ABLOCK Count
----------- --------------- ------------	----------- --------------- ------------
Line 417 TRIGGER Disabled 0	Line 419 TRIGGER Disabled 0
@item @command{trantab}	@item @command{trantab}
Displays information about any uncommitted transactions currently in-flight for this process.	Displays information about any uncommitted transactions currently in-flight for this process.

	@anchor{glstat}
	@item @command{trantab}
	Displays statistics about globals that have been opened in the current FreeM process.

@anchor{jobtab}	@anchor{jobtab}
@item @command{jobtab}	@item @command{jobtab}
Displays a summary of the FreeM job table.	Displays a summary of the FreeM job table.
Line 429 Displays a list of @code{LOCK}s held in	Line 435 Displays a list of @code{LOCK}s held in
@item @command{rbuf}	@item @command{rbuf}
Lists the status of all FreeM routine buffers.	Lists the status of all FreeM routine buffers.

@anchor{dbstats}
@item @command{dbstats}
Shows statistics for the BerkeleyDB global handler.

@anchor{wh}	@anchor{wh}
@item @command{wh}	@item @command{wh}
Forces an immediate flush of this process's @code{readline} history buffer to disk.	Forces an immediate flush of this process's @code{readline} history buffer to disk.
Line 457 Allows you to recall command number @emp	Line 459 Allows you to recall command number @emp
Launches a subshell within the FreeM direct mode, allowing the user to run operating system commands.	Launches a subshell within the FreeM direct mode, allowing the user to run operating system commands.

@example	@example
USER> !!	DEFAULT.USER> !!

Type Ctrl-D to exit from the shell	Type Ctrl-D to exit from the shell
$ uname -a	$ uname -a
Linux hesperos 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux	Linux hesperos 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux
$ exit	$ exit

USER>	DEFAULT.USER>
@end example	@end example

@item @command{!@emph{<external-command>}}	@item @command{!@emph{<external-command>}}
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}.	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}.

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>}.	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>}.

Line 482 The data value in the unsubscripted M lo	Line 484 The data value in the unsubscripted M lo
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{$TLEVEL}} is greater than zero, you will be given the opportunity to commit or rollback any pending transactions:	If you issue a @code{@ref{HALT}} command at the direct-mode prompt, you will exit out of FreeM. However, if you issue a @code{@ref{HALT}} command when @code{@ref{$TLEVEL}} is greater than zero, you will be given the opportunity to commit or rollback any pending transactions:

@example	@example
USER> TSTART	DEFAULT.USER> TSTART


TL1:USER> SET ^MYGLOBAL=1	TL1:DEFAULT.USER> SET ^MYGLOBAL=1


TL1:USER> HALT	TL1:DEFAULT.USER> HALT

UNCOMMITTED TRANSACTIONS EXIST:	UNCOMMITTED TRANSACTIONS EXIST:

Line 510 In the above example, the user selected	Line 512 In the above example, the user selected
FreeM direct mode allows you to enter M expressions directly from the direct-mode prompt, as long as they begin with a number:	FreeM direct mode allows you to enter M expressions directly from the direct-mode prompt, as long as they begin with a number:

@example	@example
USER> S DENOM=10	DEFAULT.USER> S DENOM=10


USER> 100/DENOM	DEFAULT.USER> 100/DENOM

10	10
USER>	DEFAULT.USER>
@end example	@end example

Such expressions will be immediately evaluated, and the result printed on @code{@ref{$IO}}.	Such expressions will be immediately evaluated, and the result printed on @code{@ref{$IO}}.
Line 657 Please note that FreeM is not entirely s	Line 659 Please note that FreeM is not entirely s

Returns a comma-delimited list of error conditions currently present, and is writable. An empty @code{$ECODE} indicates no errors.	Returns a comma-delimited list of error conditions currently present, and is writable. An empty @code{$ECODE} indicates no errors.

	Writing a value in the format @code{,<error-code>,} into @code{$ECODE} will raise that error condition.

@node $ESTACK	@node $ESTACK
@section $ESTACK	@section $ESTACK
@cindex $ESTACK	@cindex $ESTACK
Line 1081 SET M=$EXTRACT(NAME,1,5)	Line 1085 SET M=$EXTRACT(NAME,1,5)
It is also possible to use @code{$EXTRACT} on the left-hand side of a @code{SET} assignment in order to modify a substring:	It is also possible to use @code{$EXTRACT} on the left-hand side of a @code{SET} assignment in order to modify a substring:

@example	@example
USER> SET FOO="ABCDEFG"	DEFAULT.USER> SET FOO="ABCDEFG"


USER> SET $EXTRACT(FOO,1,3)="XYZ"	DEFAULT.USER> SET $EXTRACT(FOO,1,3)="XYZ"


USER> WRITE FOO	DEFAULT.USER> WRITE FOO

XYZDEFG	XYZDEFG
@end example	@end example
Line 1114 Formats a number according to a particul	Line 1118 Formats a number according to a particul

The first argument is the number to format.	The first argument is the number to format.

The second argument is the series of formatting codes.	The second argument is the series of formatting codes:

	@table @asis
	@item 'P' or 'p'
	Will display negative numbers within parentheses instead of showing a minus sign.
	@item , (comma)
	Will add commas as thousands separators.
	@item +
	Will include a plus sign for positive numbers. Not compatible with 'P' or 'p'.
	@item -
	Will remove the minus sign from negative numbers. Not compatible with 'p' or 'P'.
	@item 't' or 'T'
	Will place the sign after the number instead of before the number.
	@end table

	The optional third argument is a number indicating how many digits to which the fractional part of the number will be zero-padded.

@node $GET()	@node $GET()
@section $GET	@section $GET
Line 1139 The first argument is a string represent	Line 1158 The first argument is a string represent

The second argument is a string representing a valid FreeM class.	The second argument is a string representing a valid FreeM class.



@example	@example
USER> N STR=$$^%STRING	DEFAULT.USER> N STR=$$^%STRING

USER> W $INSTANCEOF("STR","^%STRING")	DEFAULT.USER> W $INSTANCEOF("STR","^%STRING")
1	1
@end example	@end example

Line 1188 The optional second argument indicates t	Line 1205 The optional second argument indicates t
@cindex $NEXT	@cindex $NEXT
@cindex intrinsic functions, $NEXT	@cindex intrinsic functions, $NEXT

	Deprecated. Use @code{$ORDER} instead.

@node $ORDER()	@node $ORDER()
@section $ORDER	@section $ORDER
@cindex $ORDER	@cindex $ORDER
@cindex intrinsic functions, $ORDER	@cindex intrinsic functions, $ORDER

	Returns the previous subscript or next subscript in a local, global, or a subset of structured system variables.

	The first argument is the subscripted local, global, or SSVN.

	The optional second argument can be @code{1} to retrieve the next subscript, or @code{-1} to return the previous.

@node $PIECE()	@node $PIECE()
@section $PIECE	@section $PIECE
@cindex $PIECE	@cindex $PIECE
Line 1215 The optional fourth argument is the fina	Line 1240 The optional fourth argument is the fina
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:	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:

@example	@example
; ^jpw="this^is^a^piece"	; ^snw="this^is^a^piece"
SET $PIECE(^jpw,"^",2)="isn't" ; => "this^isn't^a^piece"	SET $PIECE(^snw,"^",2)="isn't" ; => "this^isn't^a^piece"
@end example	@end example

@node $QLENGTH()	@node $QLENGTH()
Line 1248 Returns the number of subscripts in @emp	Line 1273 Returns the number of subscripts in @emp
@code{$QSUBSCRIPT(@emph{expr V glvn},@emph{expr V n})}	@code{$QSUBSCRIPT(@emph{expr V glvn},@emph{expr V n})}
@end example	@end example

Returns the @emph{n}th subscript of @emph{glvn}.	In the RHS form, returns the @emph{n}th subscript of @emph{glvn}.

@emph{Example}	@emph{Example}

Line 1256 Returns the @emph{n}th subscript of @emp	Line 1281 Returns the @emph{n}th subscript of @emp
@code{SET SUB=$QSUBSCRIPT("^GBL(1,2,3)",2) ; => 2}	@code{SET SUB=$QSUBSCRIPT("^GBL(1,2,3)",2) ; => 2}
@end example	@end example

	@emph{Syntax}

	@example
	@code{SET $QSUBSCRIPT(@emph{expr V glvn},@emph{expr V n})=@emph{expr} ; => ^GBL(1,4,3)}
	@end example

	In the LHS form, sets the @emph{n}th subscript of @emph{glvn} to @emph{expr}.

@node $QUERY()	@node $QUERY()
@section $QUERY	@section $QUERY
@cindex $QUERY	@cindex $QUERY
Line 1273 Returns the next subscripted reference i	Line 1306 Returns the next subscripted reference i

We will assume the following data structure exists:	We will assume the following data structure exists:
@example	@example
^jpw(1)=1	^snw(1)=1
^jpw(1,2)="foo"	^snw(1,2)="foo"
^jpw(2)=3	^snw(2)=3
^jpw(3)=""	^snw(3)=""
@end example	@end example

The following code will retrieve the next subscripted name after @code{^jpw(1)}:	The following code will retrieve the next subscripted name after @code{^snw(1)}:

@example	@example
@code{SET NEXTNAM=$QUERY(^jpw(1)) ; => ^jpw(1,2)}	@code{SET NEXTNAM=$QUERY(^snw(1)) ; => ^snw(1,2)}
@end example	@end example

@node $RANDOM()	@node $RANDOM()
Line 1379 Returns a line of code from a routine.	Line 1412 Returns a line of code from a routine.
@cindex $TRANSLATE	@cindex $TRANSLATE
@cindex intrinsic functions, $TRANSLATE	@cindex intrinsic functions, $TRANSLATE

	Replaces characters in a string.

	The first argument is a string expression representing the text to be changed.

	The second argument is a list of characters to replace.

	The third argument is a list of characters to use as the replacements for the characters in the second argument.

	@emph{Example}

	@example
	DEFAULT.USER> W $TRANSLATE("twig","wt","rb")
	brig
	@end example

@node $TYPE()	@node $TYPE()
@section $TYPE	@section $TYPE
@cindex $TYPE	@cindex $TYPE
Line 1452 Always @emph{true}	Line 1500 Always @emph{true}
@cindex intrinsic functions, $ZCALL	@cindex intrinsic functions, $ZCALL
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZCRC()	@node $ZCRC()
@section $ZCRC	@section $ZCRC
@cindex $ZCRC	@cindex $ZCRC
Line 1472 Returns a checksum of @code{arg1}.	Line 1522 Returns a checksum of @code{arg1}.
@cindex intrinsic functions, $ZDATA	@cindex intrinsic functions, $ZDATA
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZDATE()	@node $ZDATE()
@section $ZDATE	@section $ZDATE
@cindex $ZDATE	@cindex $ZDATE
Line 1496 The optional @emph{<format-string>} foll	Line 1548 The optional @emph{<format-string>} foll
@cindex intrinsic functions, $ZEDIT	@cindex intrinsic functions, $ZEDIT
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZHOROLOG()	@node $ZHOROLOG()
@section $ZHOROLOG	@section $ZHOROLOG
@cindex $ZHOROLOG	@cindex $ZHOROLOG
Line 1520 $ZHOROLOG(@emph{<date-value>},@emph{<for	Line 1574 $ZHOROLOG(@emph{<date-value>},@emph{<for
@cindex intrinsic functions, $ZKEY	@cindex intrinsic functions, $ZKEY
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZLENGTH()	@node $ZLENGTH()
@section $ZLENGTH	@section $ZLENGTH
@cindex $ZLENGTH	@cindex $ZLENGTH
@cindex intrinsic functions, $ZLENGTH	@cindex intrinsic functions, $ZLENGTH
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZLSD()	@node $ZLSD()
@section $ZLSD	@section $ZLSD
@cindex $ZLSD	@cindex $ZLSD
Line 1554 Returns the Levenshtein distance between	Line 1612 Returns the Levenshtein distance between
@cindex intrinsic functions, $ZNAME	@cindex intrinsic functions, $ZNAME
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZNEXT()	@node $ZNEXT()
@section $ZNEXT	@section $ZNEXT
@cindex $ZNEXT	@cindex $ZNEXT
@cindex intrinsic functions, $ZNEXT	@cindex intrinsic functions, $ZNEXT
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZORDER()	@node $ZORDER()
@section $ZORDER	@section $ZORDER
@cindex $ZORDER	@cindex $ZORDER
@cindex intrinsic functions, $ZORDER	@cindex intrinsic functions, $ZORDER
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZPIECE()	@node $ZPIECE()
@section $ZPIECE	@section $ZPIECE
@cindex $ZPIECE	@cindex $ZPIECE
@cindex intrinsic functions, $ZPIECE	@cindex intrinsic functions, $ZPIECE
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZPREVIOUS()	@node $ZPREVIOUS()
@section $ZPREVIOUS	@section $ZPREVIOUS
@cindex $ZPREVIOUS	@cindex $ZPREVIOUS
@cindex intrinsic functions, $ZPREVIOUS	@cindex intrinsic functions, $ZPREVIOUS
@cindex intrinsic functions, implementation-specific	@cindex intrinsic functions, implementation-specific

	Purpose unknown.

@node $ZREPLACE()	@node $ZREPLACE()
@section $ZREPLACE	@section $ZREPLACE
@cindex $ZREPLACE	@cindex $ZREPLACE
Line 1749 $$<objectName>.EXTRACT(<start>,<end>)	Line 1817 $$<objectName>.EXTRACT(<start>,<end>)
@node $$FIND	@node $$FIND
@section $$FIND	@section $$FIND

	Finds the character immediately following the first occurence of a substring within a string.

	The first argument is the substring to be located.

	The second argument is the position within the string at which to begin searching.

	See @ref{$FIND()}.

@node $$FNUMBER	@node $$FNUMBER
@section $$FNUMBER	@section $$FNUMBER

	Formats a number according to a set of formatting codes.

	The argument is a series of formatting codes. See @ref{$FNUMBER()} for details.

@node $$JUSTIFY	@node $$JUSTIFY
@section $$JUSTIFY	@section $$JUSTIFY

	Right-justifies a string based on a specified fixed length.

	The first argument is the character length of the output.

	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.

	See @ref{$JUSTIFY()} for details.

@node $$LENGTH	@node $$LENGTH
@section $$LENGTH	@section $$LENGTH

	Returns the length of the string.

@node $$PIECECOUNT	@node $$PIECECOUNT
@section $$PIECECOUNT	@section $$PIECECOUNT

	Returns the number of items in a list delimited by the character specified in the argument.

@node $$PIECE	@node $$PIECE
@section $$PIECE	@section $$PIECE

	@emph{Syntax}

	@code{$PIECE(@emph{d}[,@emph{n}[,@emph{end}]])}

	Accesses the @code{n}th through @code{end} @code{d}-delimited pieces of the string.

	The first argument is the delimiter to be used.

	The optional second argument is the first @code{d}-delimited piece to access, and defaults to @code{1}.

	The optional third argument is the final @code{d}-delimited piece to access, and defaults to the value of the third argument (@code{n}).


@node $$REPLACE	@node $$REPLACE
@section $$REPLACE	@section $$REPLACE

	@emph{Syntax}
	@code{myString.$$REPLACE(@emph{arg1},@emph{arg2})}

	Replaces all instances of @code{arg2} with @code{arg3} in @code{myString}.

@node $$REVERSE	@node $$REVERSE
@section $$REVERSE	@section $$REVERSE

	Returns the reverse of the string.

@node $$TOLOWER	@node $$TOLOWER
@section $$TOLOWER	@section $$TOLOWER

	Returns an all-lowercase version of the string.

@node $$TOUPPER	@node $$TOUPPER
@section $$TOUPPER	@section $$TOUPPER

	Returns an all-uppercase version of the string.

@node $$TRANSLATE	@node $$TRANSLATE
@section $$TRANSLATE	@section $$TRANSLATE

	Identical to @ref{$TRANSLATE()}, except that the arguments are shifted left by one, and the input string is implicit (the object).

@node Commands	@node Commands
@chapter Commands	@chapter Commands
@cindex commands	@cindex commands
Line 1826 $$<objectName>.EXTRACT(<start>,<end>)	Line 1944 $$<objectName>.EXTRACT(<start>,<end>)
* WITH:: Set prefix for future variable references.	* WITH:: Set prefix for future variable references.
* WRITE:: Write output to current input/output device.	* WRITE:: Write output to current input/output device.
* XECUTE:: Interpret string as M code.	* XECUTE:: Interpret string as M code.
* ZALLOCATE:: Alternative to @code{LOCK}.
* ZBREAK:: Unknown.	* ZBREAK:: Unknown.
* ZDEALLOCATE:: Alternative to @code{LOCK}.
* ZGO:: Unknown.	* ZGO:: Unknown.
* ZHALT:: Unknown.	* ZHALT:: Unknown.
* ZINSERT:: Insert code into routine buffer.	* ZINSERT:: Insert code into routine buffer.
Line 1861 Executes FreeM code @emph{expr V mcode}.	Line 1977 Executes FreeM code @emph{expr V mcode}.
@emph{Example (Using Variable)}	@emph{Example (Using Variable)}

@example	@example
USER> SET FOO="WRITE ""HELLO WORLD"",!"	DEFAULT.USER> SET FOO="WRITE ""HELLO WORLD"",!"
USER> @@FOO	DEFAULT.USER> @@FOO

HELLO WORLD	HELLO WORLD

USER>	DEFAULT.USER>
@end example	@end example

@emph{Example (Using String Literal)}	@emph{Example (Using String Literal)}

@example	@example
USER> @@"WRITE ""HELLO WORLD"",!"	DEFAULT.USER> @@"WRITE ""HELLO WORLD"",!"

HELLO WORLD	HELLO WORLD

USER>	DEFAULT.USER>
@end example	@end example

@emph{Example (Using Indirection)}	@emph{Example (Using Indirection)}

@example	@example
USER> SET FOO="BAR"	DEFAULT.USER> SET FOO="BAR"

USER> SET BAR="WRITE ""HELLO WORLD"",!"	DEFAULT.USER> SET BAR="WRITE ""HELLO WORLD"",!"

USER> @@@@FOO	DEFAULT.USER> @@@@FOO

HELLO WORLD	HELLO WORLD

USER>	DEFAULT.USER>
@end example	@end example


Line 1921 If the @command{>} character is supplied	Line 2037 If the @command{>} character is supplied
Launches a subshell within the FreeM direct mode, allowing the user to run operating system commands.	Launches a subshell within the FreeM direct mode, allowing the user to run operating system commands.

@example	@example
USER> !!	DEFAULT.USER> !!

Type Ctrl-D to exit from the shell	Type Ctrl-D to exit from the shell
$ uname -a	$ uname -a
Linux hesperos 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux	Linux hesperos 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux
$ exit	$ exit

USER>	DEFAULT.USER>
@end example	@end example


Line 1983 The @code{ASSERT} error is catchable whe	Line 2099 The @code{ASSERT} error is catchable whe
@emph{Example}	@emph{Example}

@example	@example
USER> SET DEBUG=1	DEFAULT.USER> SET DEBUG=1


USER> ASSERT:DEBUG 1=1	DEFAULT.USER> ASSERT:DEBUG 1=1


USER> ASSERT:DEBUG 1=0	DEFAULT.USER> ASSERT:DEBUG 1=0


>> Error ZASSERT: programmer assertion failed in SYSTEM::^%SYSINIT [$STACK = 0]	>> Error ZASSERT: programmer assertion failed in SYSTEM::^%SYSINIT [$STACK = 0]
Line 2232 FOR[@emph{:postcondition}] @emph{glvn}=@	Line 2348 FOR[@emph{:postcondition}] @emph{glvn}=@
@emph{Example}	@emph{Example}

@example	@example
USER> FOR I=1:1:10 WRITE I,!	DEFAULT.USER> FOR I=1:1:10 WRITE I,!

1	1
2	2
Line 2245 USER> FOR I=1:1:10 WRITE I,!	Line 2361 USER> FOR I=1:1:10 WRITE I,!
9	9
10	10

USER> FOR I=2:2:10 WRITE I,!	DEFAULT.USER> FOR I=2:2:10 WRITE I,!

2	2
4	4
Line 2265 FOR[@emph{:postcondition}] @emph{glvn}=@	Line 2381 FOR[@emph{:postcondition}] @emph{glvn}=@
@emph{Example}	@emph{Example}

@example	@example
USER> FOR I=60,"FOO",-3,"George",1450,$HOROLOG WRITE I,!	DEFAULT.USER> FOR I=60,"FOO",-3,"George",1450,$HOROLOG WRITE I,!

60	60
FOO	FOO
Line 2399 In the above @emph{inclusive} form, @cod	Line 2515 In the above @emph{inclusive} form, @cod
@cartouche	@cartouche
@quotation	@quotation
@emph{Note}	@emph{Note}
The below @emph{argumentless} and @emph{exclusive} forms of @code{KSUBSCRIPTS} are not implemented in FreeM, as of version 0.3.3, but are planned for a future release.	The below @emph{argumentless} and @emph{exclusive} forms of @code{KSUBSCRIPTS} are not implemented in FreeM, as of version 0.64.0-rc0, but are planned for a future release.
@end quotation	@end quotation
@end cartouche	@end cartouche

Line 2434 In the above @emph{inclusive} form, @cod	Line 2550 In the above @emph{inclusive} form, @cod
@cartouche	@cartouche
@quotation	@quotation
@emph{Note}	@emph{Note}
The below @emph{argumentless} and @emph{exclusive} forms of @code{KVALUE} are not implemented in FreeM, as of version 0.63.0-rc4, but are planned for a future release.	The below @emph{argumentless} and @emph{exclusive} forms of @code{KVALUE} are not implemented in FreeM, as of version 0.64.0-rc0, but are planned for a future release.
@end quotation	@end quotation
@end cartouche	@end cartouche

Line 2475 LOCK[@emph{:postcondition}] [+\|-]@emph{n	Line 2591 LOCK[@emph{:postcondition}] [+\|-]@emph{n

@emph{Example}	@emph{Example}

This example will increment the lock counter for @code{^JPW} and decrement the lock counter for @code{^MJR}.	This example will increment the lock counter for @code{^SNW} and decrement the lock counter for @code{^MJR}.

@example	@example
LOCK +^JPW,-^MJR	LOCK +^SNW,-^MJR
@end example	@end example

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.	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.
Line 2551 NEW@emph{:postcondition} @emph{name}=@em	Line 2667 NEW@emph{:postcondition} @emph{name}=@em

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.	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.

	@emph{Syntax}
	@example
	NEW@emph{:postcondition} @emph{name}=$%@emph{^CLASS}(@emph{initializer-list})
	@end example

	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).

@node OPEN	@node OPEN
@section OPEN	@section OPEN
@cindex OPEN	@cindex OPEN
Line 2914 Closes all global data files open in the	Line 3037 Closes all global data files open in the
VIEW 21	VIEW 21
@end example	@end example

@item @code{29} - Symbol Table Copy
Copies the primary symbol table's contents to the alternate symbol table. Takes no arguments.

@emph{Syntax}
@example
VIEW 29
@end example

@item @code{52} - Set G0 Input Translation Table for @code{$IO}	@item @code{52} - Set G0 Input Translation Table for @code{$IO}

@emph{Syntax}	@emph{Syntax}
Line 3070 If @emph{tvexpr} evaluates to @emph{true	Line 3185 If @emph{tvexpr} evaluates to @emph{true
VIEW 83:@emph{tvexpr}	VIEW 83:@emph{tvexpr}
@end example	@end example

@item @code{87} - Date Type Definition
We believe this defines date formats for @code{$ZDATE}, but we have not yet figured out how it works.

@emph{Syntax}
@example
; Syntax unknown
@end example

@item @code{88} - Time Type Definition
We believe this defines time formats for @code{$ZTIME}, but we have not yet figured out how it works.

@emph{Syntax}
@example
; Syntax unknown
@end example

@item @code{91} - Set Default Expression for Missing @code{QUIT} Expression
Sets the default expression to be printed when a @code{QUIT} is encountered where a @code{QUIT} argument would be expected, but was not provided. We're not entirely sure what this does.

@emph{Syntax}
@example
; Syntax unknown
@end example

@item @code{92} - Set Type Mismatch Error Flag on @code{EUR2DEM}	@item @code{92} - Set Type Mismatch Error Flag on @code{EUR2DEM}
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.	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.

Line 3215 WATCH[@emph{:postcondition}] [+\|-\|?]@emp	Line 3306 WATCH[@emph{:postcondition}] [+\|-\|?]@emp
@end example	@end example


The following example demonstrates turning watchpoint processing on and adding a watchpoint for global variable @code{^jpw(1)}. It then changes the value of @code{^jpw(1)}.	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)}.

@example	@example
USER> WATCH	DEFAULT.USER> WATCH

Watchpoints enabled.	Watchpoints enabled.

USER> WATCH +^JPW(1)	DEFAULT.USER> WATCH +^SNW(1)

Added '^JPW("1")' to the watchlist.	Added '^SNW("1")' to the watchlist.

USER> SET ^JPW(1)="new value"	DEFAULT.USER> SET ^SNW(1)="new value"

>> WATCHPOINT: ^JPW("1") => 'new value' (changed 1 times)	>> WATCHPOINT: ^SNW("1") => 'new value' (changed 1 times)

@end example	@end example

The following example will remove that watchpoint:	The following example will remove that watchpoint:

@example	@example
USER> WATCH -^JPW(1)	DEFAULT.USER> WATCH -^SNW(1)

Removed '^JPW("1")' from the watchlist.	Removed '^SNW("1")' from the watchlist.

USER> WATCH ?^JPW(1)	DEFAULT.USER> WATCH ?^SNW(1)

'^JPW("1")' is not being watched.	'^SNW("1")' is not being watched.
@end example	@end example

@node WITH	@node WITH
Line 3251 USER> WATCH ?^JPW(1)	Line 3342 USER> WATCH ?^JPW(1)
@cindex commands, non-standard	@cindex commands, non-standard
@emph{FreeM Extension}	@emph{FreeM Extension}

	NOTE: This command may be deprecated and removed in future FreeM releases.

Sets a prefix to be applied to all subsequent local variable or constant references.	Sets a prefix to be applied to all subsequent local variable or constant references.

@emph{Syntax}	@emph{Syntax}
Line 3280 In the above argumentless form, clears t	Line 3373 In the above argumentless form, clears t
@cindex XECUTE	@cindex XECUTE
@cindex commands, XECUTE	@cindex commands, XECUTE

@node ZALLOCATE
@section ZALLOCATE
@cindex ZALLOCATE
@cindex commands, ZALLOCATE
@cindex commands, implementation-specific
@cindex commands, non-standard
@emph{FreeM Extension}

@node ZBREAK	@node ZBREAK
@section ZBREAK	@section ZBREAK
@cindex ZBREAK	@cindex ZBREAK
Line 3297 In the above argumentless form, clears t	Line 3382 In the above argumentless form, clears t
@cindex commands, non-standard	@cindex commands, non-standard
@emph{FreeM Extension}	@emph{FreeM Extension}

@node ZDEALLOCATE
@section ZDEALLOCATE
@cindex ZDEALLOCATE
@cindex commands, ZDEALLOCATE
@cindex commands, implementation-specific
@cindex commands, non-standard
@emph{FreeM Extension}

@node ZGO	@node ZGO
@section ZGO	@section ZGO
@cindex ZGO	@cindex ZGO
Line 3793 Returns or sets the maximum number of ch	Line 3870 Returns or sets the maximum number of ch
Returns or sets the maximum number of characters of a single global subscript, from 1-255.	Returns or sets the maximum number of characters of a single global subscript, from 1-255.

@item @code{SINGLE_USER} +R +U -D	@item @code{SINGLE_USER} +R +U -D
If set to @code{1}, FreeM will skip all file locking operations on globals, as well as the @code{LOCK} and @code{ZALLOCATE} tables. If set to @code{0}, FreeM will enforce file locking on both.	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.

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 and @code{LOCK}/@code{ZALLOCATE} table corruption!	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.

@item @code{CHARACTER} +R -U -D	@item @code{CHARACTER} +R -U -D
Returns the character set of the job.	Returns the character set of the job.
Line 3806 Returns or sets the current working dire	Line 3883 Returns or sets the current working dire
@item @code{OPEN} +R -U -D	@item @code{OPEN} +R -U -D
The @code{^$JOB($JOB,"OPEN",<channel>} subscripts list the open I/O channels in the specified job.	The @code{^$JOB($JOB,"OPEN",<channel>} subscripts list the open I/O channels in the specified job.

@item @code{ENGINES} +R -U -D
Returns or sets the storage engines for various FreeM subsystems.

The following table lists the types of storage engines that can be defined.

@table @asis

@item @code{GLOBAL} +R +U -D
Returns or sets the global handler for a particular FreeM namespace:

The following code would set the global handler for the @code{SYSTEM} namespace to @code{BERKELEYDB}:

@code{SET ^$JOB($JOB,"ENGINES","GLOBAL","SYSTEM")="BERKELEYDB"}

@item @code{LOCAL} +R -U -D
Returns the local handler for a particular FreeM namespace. Always @code{BUILTIN} in the current FreeM release.

@end table

@item @code{BERKELEYDB,FLUSH_THRESHOLD} +R +U -D	@item @code{BERKELEYDB,FLUSH_THRESHOLD} +R +U -D
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.	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.

Line 4114 Forces a number to positive, whether pos	Line 4172 Forces a number to positive, whether pos
@section Unary -	@section Unary -
@cindex operators, unary -	@cindex operators, unary -

	Forces a number to negative, whether positive or negative. Also forces numeric coercion of strings.

@node +	@node +
@section + (Add)	@section + (Add)
@cindex operators, +	@cindex operators, +

	@emph{Syntax}

	@example
	S X=1+2 ; => 3
	@end example

	Adds numbers together.

@node +=	@node +=
@section += (Add/Assign)	@section += (Add/Assign)
@cindex operators, +=	@cindex operators, +=

	@emph{Syntax}

	@example
	S X=5
	S X+=3 ; => 8
	@end example

	Increments the variable on the LHS by the value on the RHS.

@node ++	@node ++
@section ++ (Postfix Increment)	@section ++ (Postfix Increment)
@cindex operators, ++	@cindex operators, ++

	Increments a variable by 1.

@node -	@node -
@section - (Subtract)	@section - (Subtract)
@cindex operators, -	@cindex operators, -

	Subtracts one number from another.

@node -=	@node -=
@section -= (Subtract/Assign)	@section -= (Subtract/Assign)
@cindex operators, -=	@cindex operators, -=

	@emph{Syntax}

	@example
	S X=5
	S X-=3 ; => 2
	@end example

	Decrements the variable on the LHS by the value on the RHS.

@node --	@node --
@section -- (Postfix Decrement)	@section -- (Postfix Decrement)
@cindex operators, --	@cindex operators, --

	Decrements the variable by one.

@node *	@node *
@section * (Multiply)	@section * (Multiply)
@cindex operators, *	@cindex operators, *

	Multiplies one number by another.

@node *=	@node *=
@section *= (Multiply/Assign)	@section *= (Multiply/Assign)
@cindex operators, *=	@cindex operators, *=



@node /	@node /
@section / (Divide)	@section / (Divide)
@cindex operators, /	@cindex operators, /
Line 4309 An @code{INTEGER} is an interpretation o	Line 4405 An @code{INTEGER} is an interpretation o
@cindex data types, REAL	@cindex data types, REAL
@cindex types, REAL	@cindex types, REAL

	A @code{REAL} is a numeric interpretation of data including a fractional part.

@node STRING	@node STRING
@section STRING	@section STRING
@cindex data types, STRING	@cindex data types, STRING
@cindex types, STRING	@cindex types, STRING

	A @code{STRING} is any data in FreeM.

@node Custom Types (Classes)	@node Custom Types (Classes)
@section Custom Types (Classes)	@section Custom Types (Classes)
@cindex data types, custom	@cindex data types, custom
Line 4386 See @ref{Classes}.	Line 4486 See @ref{Classes}.
@cindex programming, object-oriented	@cindex programming, object-oriented

@menu	@menu
* Classes:: The basis of object-oriented programming.	* Classes:: The basis of object-oriented programming.
	* Inheritance:: Basing one class upon another.
	* Methods:: Attaching code to a class.
	* Public and Private Variables:: Managing class member access.
@end menu	@end menu

@node Classes	@node Classes
@section Classes	@section Classes

@menu	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:
* Inheritance:: Basing one class upon another.
* Methods:: Attaching code to a class.	@example
* Public Variables:: Variables visible outside of a class.	MYCLASS(THIS,INIT):OBJECT ; Constructor for MYCLASS, inherits OBJECT
* Private Variables:: Variables only visible within a class.	; two private variables
@end menu	S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
	S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
	Q
	;
	DESTROY(THIS) ; This is the destructor
	Q
	@end example

	The above example demonstrates general class syntax.

	@node Constructors
	@subsection Constructors

	A @emph{constructor} is an M entry point that is called when a new instance of a class is created.

	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}.

	@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.

	A constructor looks like this:

	@example
	%FRACTION(THIS,INIT):OBJECT ;
	S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
	S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
	Q
	@end example

	@emph{Syntax}
	@example
	@emph{<class-name>}(THIS,INIT)[:@emph{<superclass>}]
	@end example

	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}.

	@node Destructors
	@subsection Destructors
	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}).

	The destructor should be used to clean up any resources used by class methods.

	A destructor looks like this:

	@example
	DESTROY(THIS) ;
	; free any resources that should be freed at the end of the object's lifetime
	Q
	@end example

@node Inheritance	@node Inheritance
@subsection Inheritance	@section Inheritance

	Every class you create will automatically inherit the methods and functionality of the @code{OBJECT} class, supplied with FreeM.

	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.

	Inheritance is achieved by specifying the name of the superclass in the constructor:

	@example
	CLASS(THIS,INIT):SUPERCLASS
	@end example

	@node Runtime Polymorphism
	@subsection Runtime Polymorphism

	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.

	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.

@node Methods	@node Methods
@subsection Methods	@section Methods
	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).

	The following class (@code{MYCLASS}) has a constructor, a destructor, and a method called @code{MYMETHOD}:

	@example
	%MYCLASS(THIS,INIT) ;
	Q THIS
	DESTROY(THIS) ;
	Q
	MYMETHOD(THIS) ;
	Q "VALUE"
	@end example

	@node Public and Private Variables
	@section Public and Private Variables

	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.

	The below constructor for a @code{FRACTION} class defines two private fields:

	@example
	%FRACTION(THIS,INIT):OBJECT ;
	S THIS("NUMERATOR"):PRIVATE=$P(INIT,"/",1)
	S THIS("DENOMINATOR"):PRIVATE=$P(INIT,"/",2)
	Q
	@end example

@node Public Variables	Either of the following commands will create a public field:
@subsection Public Variables

@node Private Variables	@example
@subsection Private Variables	S THIS("VARNAM")="Initial Value"
	S THIS("VARNAM"):PUBLIC="Initial Value"
	@end example

	Attempting to access private fields from outside of the class will raise error condition @code{ZOBJFLDACCV}.

@node Libraries	@node Libraries
@chapter Libraries	@chapter Libraries
Line 4477 You may also use an expression that reso	Line 4673 You may also use an expression that reso
WRITE ^\|NS\|VA(200,0),!	WRITE ^\|NS\|VA(200,0),!
@end example	@end example

@section File Path Extended Global References
@cindex extended global references, file path

If a namespace is configured to use the @code{BUILTIN} global handler, FreeM supports accessing a global data file by way of its filesystem path.

The following file path extended global reference will write the value of @code{^VA(200,0)}, assuming the @code{^VA} data file exists at path @code{/home/jpw/^VA}:

@example
WRITE ^/home/jpw/VA(200,0),!
@end example


@node Global Aliasing	@node Global Aliasing
@chapter Global Aliasing	@chapter Global Aliasing
@cindex aliasing, global	@cindex aliasing, global
Line 4558 Used for globals that @emph{did} exist p	Line 4742 Used for globals that @emph{did} exist p
The below example shows a few global operations and checkpoints for a transaction in-flight using the @code{trantab} direct-mode command:	The below example shows a few global operations and checkpoints for a transaction in-flight using the @code{trantab} direct-mode command:

@verbatim	@verbatim
TL1:USER> trantab	TL1:DEFAULT.USER> trantab
$TLEVEL 1*	$TLEVEL 1*
Operations for Transaction ID: 6ea14aad-b8f1-47f9-9f52-4f513f892bc0 [RESTARTABLE SERIAL]	Operations for Transaction ID: 6ea14aad-b8f1-47f9-9f52-4f513f892bc0 [RESTARTABLE SERIAL]

Line 4566 TL1:USER> trantab	Line 4750 TL1:USER> trantab
------- ------ --------	------- ------ --------
1 SET ^FOO=3	1 SET ^FOO=3
2 KILL ^FOO	2 KILL ^FOO
3 SET ^jpw=10	3 SET ^snw=10
4 SET ^BRANDNEW=6	4 SET ^BRANDNEW=6

Global checkpoints:	Global checkpoints:
Line 4574 TL1:USER> trantab	Line 4758 TL1:USER> trantab
GLOBAL MODE FILES	GLOBAL MODE FILES
------ ---- -----	------ ---- -----
^BRANDNEW CP_REMOVE IN: /usr/local/var/freem/USER/globals/^BRANDNEW	^BRANDNEW CP_REMOVE IN: /usr/local/var/freem/USER/globals/^BRANDNEW
^jpw CP_RESTORE IN: /usr/local/var/freem/USER/globals/^jpw	^snw CP_RESTORE IN: /usr/local/var/freem/USER/globals/^snw
OUT: /usr/local/var/freem/USER/globals/^jpw.23390.1.chk	OUT: /usr/local/var/freem/USER/globals/^snw.23390.1.chk
^FOO CP_RESTORE IN: /usr/local/var/freem/USER/globals/^FOO	^FOO CP_RESTORE IN: /usr/local/var/freem/USER/globals/^FOO
OUT: /usr/local/var/freem/USER/globals/^FOO.23390.1.chk	OUT: /usr/local/var/freem/USER/globals/^FOO.23390.1.chk
@end verbatim	@end verbatim
Line 4794 You can also set up a trigger that appli	Line 4978 You can also set up a trigger that appli

This routine is the implementation of the @code{$ZCOLUMNS} intrinsic special variable.	This routine is the implementation of the @code{$ZCOLUMNS} intrinsic special variable.

@section ^%SYSINIT	@section %SYSINIT
@cindex ^%SYSINIT	@cindex %SYSINIT
@cindex system library routines, ^%SYSINIT	@cindex system library routines, %SYSINIT

This routine is the default startup routine for FreeM running in direct mode.	This routine is the default startup routine for FreeM running in direct mode.

Line 4818 This routine is the implementation of th	Line 5002 This routine is the implementation of th
@chapter Interrupt Handling	@chapter Interrupt Handling
@cindex interrupt handling	@cindex interrupt handling

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 daemon, or another external process, one of two things can happen, depending on the state of the @code{$ZI} special variable:	When FreeM receives the @code{SIGINT} signal, either by pressing @code{Ctrl-C} during program execution, or by external signal from the operating system, the FreeM environment daemon, or another external process, one of two things can happen, depending on the state of the @code{$ZI} special variable:

@table @asis	@table @asis
@item @code{$ZI} evaluates @emph{true}	@item @code{$ZI} evaluates @emph{true}
Line 5071 Custom error messages for @code{ZUSERERR	Line 5255 Custom error messages for @code{ZUSERERR
For example:	For example:

@example	@example
USER> S ^$JOB($JOB,"USER_ERRORS","UBLACKHOLE")="black hole encountered"	DEFAULT.USER> S ^$JOB($JOB,"USER_ERRORS","UBLACKHOLE")="black hole encountered"


USER> THROW UBLACKHOLE	DEFAULT.USER> THROW UBLACKHOLE


>> Error UBLACKHOLE: black hole encountered in SYSTEM::^%SYSINIT [$STACK = 0]	>> Error UBLACKHOLE: black hole encountered in SYSTEM::^%SYSINIT [$STACK = 0]
Line 5798 The FreeM @code{LOCK} table.	Line 5982 The FreeM @code{LOCK} table.

Supported actions are @code{list} and @code{remove}.	Supported actions are @code{list} and @code{remove}.

@item zallocate
The FreeM @code{ZALLOCATE} table.

No actions yet implemented.

@item journal	@item journal
FreeM after-image journaling.	FreeM after-image journaling.

Line 6024 Module headers should adhere to the foll	Line 6203 Module headers should adhere to the foll
* binding library	* binding library
*	*
*	*
* Author: Serena Willis <jpw@coherent-logic.com>	* Author: Serena Willis <snw@coherent-logic.com>
* Copyright (C) 1998 MUG Deutschland	* Copyright (C) 1998 MUG Deutschland
* Copyright (C) <Year> Coherent Logic Development LLC	* Copyright (C) <Year> Coherent Logic Development LLC
*	*

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