SNOBOL4EXT(1) CSNOBOL4 Manual SNOBOL4EXT(1)NAMEsnobol4ext - 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, -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 &FILE, &GCTIME, >RACE &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().
Scientific notation
REAL number syntax has been expanded to allow exponents of the
form: ANY('Ee') ('+' | '-' | ”) SPAN('0123456789'). Exponential
format reals need not contain a decimal point.
SPITBOL operators
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. 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.
TERMINAL I/O variable
The variable TERMINAL is associated with the standard error file
descriptor for both input and output.
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.
TRACE() of additional keywords
&ERRTEXT and &STFCOUNT can be traced.
Value TRACE() on pattern match assignments
variable changes by . and $ operators are visible via value trace.
BUGS
A lot of stuff still needs to move to other pages!
Group the keywords, control lines, functions, operators together!
SEE ALSOsnobol4(1). snobol4ctrl(1), snobol4func(1), snobol4key(1).
CSNOBOL4B 2.0 January 1, 2015 SNOBOL4EXT(1)
