Dot Variables

Updated July 2020; see History

Dot variables, so named because they begin with a period (dot), are read-only system variables useful for retrieving certain kinds of information like the date, program name, etc. In many cases, the same information is available via other methods, such as subroutines, but the dot variable approach is generally the most elegant, efficient, and transparent. They were originally considered part of the d/Basic extensions (COMPIL /D), because most of them originated with d/Basic. But over time, A-Shell has added its own dot variables and they are available as part of the A-Shell extensions (COMPIL/X:2).

Extension	Notes
.ACCOUNT	Evaluates to the user’s current ppn (e.g. "100,22").
.ARGCNT	Number of parameters passed in the last function, procedure call, or SBX.
.CCYYMMDD	Returns current date in CCYYMMDD format.
.DATE	Returns the date as a decimal number which displays as MMDDYY. So March 16, 2009 should return the numeric value 31609.
.DDMMYY	Returns current date in DDMMYY format
.DEVICE	Evaluates to the user’s current device (e.g. "DSK0:")
.EXPERIENCE	Evaluates to the numeric value 100 (since "experience" level is not one of the AMOS job attributes that is emulated under A-Shell).
.FALSE	.TRUE and .FALSE may be used as self-documenting replacements for -1 and 0.
.FN'xxx	Used to simplify referencing the result of a previously called function without having to map a variable and explicitly assign the value to it. See Implicit Function Return Value Capture.
.JOBNAME	Evaluates to the jobname.
.LAST_LABEL	Name of last label passed. Requires ++PRAGMA TRACK_LAST_LABEL.
.LAST_ROUTINE	Name of last called function or procedure. Requires ++PRAGMA TRACK_LAST_ROUTINE.
.LINENO	Returns the last line number, similar to err(1) except without requiring an error. Not to be confused with the dot function .LINENO(ch) (which returns the physical line # since the last page break in the output file open on the specified channel).
.LOCATION	Returns the current program location counter, i.e. the offset in bytes from the start of the current program (RUN, LIT or SBX) to the current statement position. Note that the location counter is generally represented in hex (as it appears in the LSX files created by the compiler /LF switch), so you would probably want to print it using the SOSLIB function Fn'Dec2Hex(.LOCATION).
.MILLITIME	Returns number of milliseconds since midnight.
.MICROTIME	Returns number of microseconds since midnight. Note that due to quirks of the system scheduling clocks on different platforms, the resolution of the results may not be as granular as one might expect.
.MMDDYY	Returns current date in MMDDYY format.
.MONTH	Evaluates to the 3 character abbreviation for the current month.
.NEST_LEVEL	Number of levels deep with nested function/procedure calls.
.NULL	Special string value distinguished from the empty string "" with particular uses. Also see .NULL Files.
.PGMNAME	Evaluates to the current program name.
.PGMVERSION	Evaluates to the current program version (e.g. "1.2A(100)").
SBXNAME	Returns name of current SBX or "" if not applicable.
.SBXVERSION	Returns version string for current SBX or "" if NA.
.TERMINAL	Evaluates to the current TRMDEF name.
.TIME	Evaluates to the current time, in HHMMSS format.
.TRUE	.TRUE and .FALSE may be used as self-documenting replacements for -1 and 0.
.USERNAME	Evaluates to the user name.
.YYMMDD	Evaluates to the current date in YYMMDD (String) format.