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SNOBOL4EXT(1)			CSNOBOL4 Manual			 SNOBOL4EXT(1)

NAME
       snobol4ext - CSNOBOL4 extensions

DESCRIPTION
       This  page  describes  extensions  to  the  Bell	Telephone Laboratories
       portable	implementation of SNOBOL4 in snobol4(1).

       ARRAY/TABLE access
	   Multiple ARRAY and/or TABLE index operations	may appear in  a  row,
	   without having to resort to use of the ELEMENT function, so long as
	   no intervening spaces (or line continuations) appear.

       Case folding
	   By  default	the compiler folds identifiers and directives to upper
	   case, so programs can be entered in either  case:  see  snobol4(1),
	   -CASE in snobol4ctrl(1), &CASE in snobol4key(1).

       Control lines
	   The	following  additional  "control	lines" are implemented:	-CASE,
	   -COPY,  -BLOCKS/-NOBLOCKS,  -ERROR/-NOERRORS,  -EXECUTE/-NOEXECUTE,
	   -HIDE, -INCLUDE, -LINE: See snobol4ctrl(1).

       Functions
	   The	 following   additional	 functions  are	 implemented:  ATAN(),
	   BREAKX(), CHAR(), CHOP() COS(), DATE(),  DELETE(),  EXP(),  FILE(),
	   FILE_ABSPATH(),    FILE_ISDIR()   FREEZE(),	 FUNCTION(),   HOST(),
	   IO_FINDUNIT() LABEL(), LEQ(), LGE(),	 LLE(),	 LLT(),	 LN(),	LNE(),
	   LOG(),  LPAD(),  ORD(), RENAME(), REVERSE(),	RPAD(),	RSORT(), SET()
	   SETEXIT(), SIN(), SORT(), SQRT(), SSET(), SUBSTR(), TAN(),  THAW(),
	   VDIFFER(): see snobol4func(1).

       Keywords
	   The	following additional keywords are implemented: &CASE, &DIGITS,
	   &ERRTEXT &FATAL, &FATALLIMIT, &FILE,	 &GCTIME,  &GTRACE  &LASTFILE,
	   &LASTLINE, &LCASE, &LINE, &MAXINT, &PARM, &PI, &STEXEC, &UCASE: see
	   snobol4key(1).

       REAL numbers in INTEGER contexts
	   REAL	 numbers  (or strings convertible to REAL) are accepted	in all
	   contexts  which  previously	required   an	INTEGER	  (or	string
	   convertible	to  INTEGER).  Contexts	include	TABLE(), ITEM(), array
	   indices, INPUT(), OUTPUT(), SET(), keyword values, CHAR(),  RPAD(),
	   LPAD(), FIELD(), COLLECT(), DUMP(), DUPL(), OPSYN(),	SUBSTR() added
	   in CSNOBOL4 0.99.44.

       Scientific notation
	   REAL	 number	 syntax	 has  been  expanded to	allow exponents	of the
	   form: ANY('Ee') ('+'	| '-' |	 ")  SPAN('0123456789')	 --  added  in
	   CSNOBOL4 0.98.

	   Exponential format reals need not contain a decimal point
	    added in CSNOBOL4 0.99.44.

       SPITBOL extensions
	   For	compatibility with SNOBOL4+, certain SPITBOL extensions	can be
	   enabled and disabled	using the -PLUSOPS directive.  -PLUSOPS	 0  or
	   -PLUSOPS  disables SPITBOL operators, while -PLUSOPS	n where	n is a
	   non-zero integer enables them.  SPITBOL extensions are  enabled  by
	   default.  Extensions	controlled by PLUSOPS are as follows:

	   The	SPITBOL	scan (?) and assignment	(=) operators have been	added.
	   A pattern match can appear within an	expression,  and  returns  the
	   matched string as its value.	 Similarly assignment can appear in an
	   expression,	and  returns the assigned value. An assignment after a
	   scan	(ie; STRING ? PATTERN =	VALUE) performs	a  scan	 and  replace.
	   Assignment  is  right  associative,	and has	the lowest precedence,
	   while scan is left associative and has  a  precedence  just	higher
	   than	assignment.

	   The	SPITBOL	 selection/alternative construction can	be used	in any
	   expression.	It consists of a comma separated list  of  expressions
	   inside  parentheses.	  The  expressions  are	 evaluated  until  one
	   succeeds, and its value is returned.	 Abuse	of  this  construction
	   may result in incomprehensible code.

	   The	type  NUMERIC with CONVERT() and the removal of	leading	spaces
	   from	strings	converted to numbers (implicitly  or  explicitly)  are
	   also	legal when SPITBOL extensions are enabled.

       TERMINAL	I/O variable
	   The	variable  TERMINAL  is associated with the standard error file
	   descriptor for both input and output	(replaces PUNCH	variable).

       TRACE() function	type argument
	   The second argument of the TRACE() function can be abbreviated to a
	   single letter: C (CALL), F (FUNCTION), K (KEYWORD),	L  (LABEL),  R
	   (RETURN), or	V (VALUE) as in	Macro SPITBOL.

       Keyword trace
	   TRACE() works on &STFCOUNT keyword added in CSNOBOL4	0.99.44.

       Value TRACE() on	pattern	match assignments
	   variable changes by . and $ operators are visible via value trace.

BUGS
       Add CSNOBOL4 version where each extension added?

       Group the keywords, control lines, functions, operators together?

SEE ALSO
       snobol4(1).  snobol4ctrl(1), snobol4func(1), snobol4key(1).

CSNOBOL4B 2.3.1			March 31, 2022			 SNOBOL4EXT(1)

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