Diff for /freem/doc/freem.texi between versions 1.22 and 1.30

version 1.22, 2025/04/10 14:37:20 version 1.30, 2025/04/18 22:12:29
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.  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  @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}.  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}.
   
 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.  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  @cindex options, command-line
Line 279  Allows your M routines to be used as UNI Line 278  Allows your M routines to be used as UNI
 Selects the FreeM namespace to be entered on startup. Must be defined in @file{/etc/<environment>/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 379  Copyright (C) 2014, 2020, 2021 Coherent Line 378  Copyright (C) 2014, 2020, 2021 Coherent
 USER>  USER>
 @end example  @end example
   
 The prompt (@code{DEFAULT.USER>}) 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{$TLEVEL}}:  The prompt (@code{DEFAULT.USER>}) displays the current environment and namespace, @code{DEFAULT} and @code{USER}, respsectively. If any uncommitted direct-mode transactions have been started, the prompt will change to reflect the current value of @code{@ref{$TLEVEL}}:
   
 @example  @example
 TL1:DEFAULT.USER>  TL1:DEFAULT.USER>
Line 436  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 475  DEFAULT.USER> Line 470  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 664  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 1134  Will include a plus sign for positive nu Line 1131  Will include a plus sign for positive nu
 Will remove the minus sign from negative numbers. Not compatible with 'p' or 'P'.  Will remove the minus sign from negative numbers. Not compatible with 'p' or 'P'.
 @item 't' or 'T'  @item 't' or 'T'
 Will place the sign after the number instead of before the number.  Will place the sign after the number instead of before the number.
 @end @table  @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.  The optional third argument is a number indicating how many digits to which the fractional part of the number will be zero-padded.
   
Line 1208  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 1235  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 $QLENGTH()
Line 1268  Returns the number of subscripts in @emp Line 1273  Returns the number of subscripts in @emp
 @code{$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 1276  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 1293  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 1399  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 1472  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 1492  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 1516  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 1540  $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 1574  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 1769  $$<objectName>.EXTRACT(<start>,<end>) Line 1817  $$<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 1846  $$<objectName>.EXTRACT(<start>,<end>) Line 1944  $$<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 2419  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 2495  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 2571  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 2934  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 3090  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 3235  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
 DEFAULT.USER> WATCH  DEFAULT.USER> WATCH
     
 Watchpoints enabled.  Watchpoints enabled.
     
 DEFAULT.USER> WATCH +^JPW(1)  DEFAULT.USER> WATCH +^SNW(1)
     
 Added '^JPW("1")' to the watchlist.  Added '^SNW("1")' to the watchlist.
     
 DEFAULT.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
 DEFAULT.USER> WATCH -^JPW(1)  DEFAULT.USER> WATCH -^SNW(1)
     
 Removed '^JPW("1")' from the watchlist.  Removed '^SNW("1")' from the watchlist.
     
 DEFAULT.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 3271  DEFAULT.USER> WATCH ?^JPW(1) Line 3342  DEFAULT.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 3300  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 3317  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 3813  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 3826  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 4134  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 4329  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 4406  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 Variables   @node Public and Private Variables 
 @subsection Public Variables  @section Public and Private Variables
   
 @node 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.
 @subsection Private Variables  
   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   
   
   Either of the following commands will create a public field:
   
   @example
     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 4574  TL1:DEFAULT.USER> trantab Line 4750  TL1:DEFAULT.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 4582  TL1:DEFAULT.USER> trantab Line 4758  TL1:DEFAULT.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 4802  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 5806  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 6032  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
  *   *

Removed from v.1.22  
changed lines
  Added in v.1.30


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