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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, with-
	 out having to resort to use of the ELEMENT function, so long as no  in-
	 tervening 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,  -IN-
	 CLUDE, -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(),  RE-
	 NAME(),  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, &ER-
	 RTEXT &FATAL, &FATALLIMIT, &FILE, &GCTIME,  &GTRACE  &LASTFILE,  &LAST-
	 LINE,	 &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  con-
	 texts	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(), COL-
	 LECT(), 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 en-
	 abled and disabled using the -PLUSOPS directive.  -PLUSOPS 0  or  -PLU-
	 SOPS disables SPITBOL operators, while -PLUSOPS n where n is a non-zero
	 integer  enables them.  SPITBOL extensions are enabled by default.  Ex-
	 tensions 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 associa-
	 tive and has a precedence just higher than assignment.

	 The SPITBOL selection/alternative construction can be used in	any  ex-
	 pression.   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  incompre-
	 hensible 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 de-
	 scriptor 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 (RE-
	 TURN), 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)
NAME | DESCRIPTION | BUGS | SEE ALSO
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