1SNOBOL4(1) General Commands Manual SNOBOL4(1)
2
6 snobol4 - SNOBOL4 interpreter
7
9 snobol4 [ options ... ] [ file(s) ... ] [ params ... ]
10
13 This manual page describes a port of the original Bell Telephone Labs
14 (BTL) Macro Implementation of SNOBOL4 (MAINBOL) to machines with ILP32
15 (32-bit int/long/pointer) or LP64 (64-bit long/pointer) C compilers by
16 Philip L. Budne. The language and it's implementation are described in
17 [1] and [2]. Extensions from Catspaw SNOBOL4+, SPITBOL and SITBOL have
18 been added. This page discusses only the changes/extensions.
19 Limitations
22 All aspects of the language are implemented except;
23 · Trapping of arithmetic exceptions.
25 · LOAD() can be used to access external functions on most plat‐
27 forms, but not all. External functions can be staticly linked
28 (poor man's loading) into the snobol4 executable ALL platforms.
29 See /usr/local/lib/snobol4/load.txt for more information.
30 Changes
33 The following behaviors have been changed from the original Macro
34 SNOBOL4;
35 · Listings are disabled by default. Default listing side (when
37 enabled by -LIST or the -l command option is LEFT. Listings are
38 directed to standard output.
39 · Error messages, the startup banner and statistics are directed
41 to standard error. Compilation error messages (including erro‐
42 neous lines) appear on standard error as well as in the list‐
43 ings. Error messages now reference the source file name and
44 line number.
45 · Character set (see below).
47 · The PUNCH output variable no longer exists (see TERMINAL vari‐
49 able below).
50 · I/O is not performed using FORTRAN I/O. The 3rd argument to the
52 OUTPUT() and INPUT() functions are interpreted as a string of
53 I/O options (see below).
54 · Control lines and comment characters are valid after the end of
56 string (;) statement separator. Listing statement numbers show
57 the statement number of the LAST statement on the line (rather
58 than the first).
59 · Setting the &ABEND keyword causes a core dump upon termination!
61 · The value of the &CODE keyword determines the exit status of the
63 snobol4 application.
64 · The DATE() function returns strings of the form: MM/DD/YYYY
66 HH:MM:SS. See extensions section for arguments to the DATE()
67 function.
68 · Keyword &STLIMIT now defaults to -1. When &STLIMIT is less than
70 zero there is no limit to the number of statements executed, and
71 &STCOUNT is not incremented.
72 · VALUE tracing applies to variables modified by immediate value
74 assignment ($ operator) and value assignment (. operator) during
75 pattern matching.
76 · The BACKSPACE() function is not implemented. Use the SET() func‐
78 tion instead.
79 · I/O unit numbers up to 256 can be used.
81 · Attempts to output on a closed unit generates a fatal “Output
83 error”
84 Character set
87 snobol4(1) is 8-bit clean, and uses the native character set. Any
88 8-bit byte is accepted as a SNOBOL datum or in a string constant of a
89 SNOBOL source program. The value of the SNOBOL protected keyword
90 &ALPHABET is a 256-character string of all bytes from 0 to 255, in
91 ascending order.
92 On ASCII based systems, any character with the 8th bit set is treated
95 as "alphabetic", and can start, or be used in identifiers and labels.
96 This includes characters from the "upper half" of national character
97 sets and all bytes resulting from the UTF-8 encoding of Unicode charac‐
98 ters.
99 Programs may be entered in mixed case; By default lower case identi‐
102 fiers are folded to upper case (see &CASE and -CASE extensions below).
103 Case folding is performed by using the C library islower(3) test, and
104 then using toupper(3) to convert the lower-case characters to upper
105 case. When using UTF-8 encoded characters in code, case folding should
106 be disabled, to prevent any bytes which appear to be lower case in the
107 current locale from being modified.
108 The following operator character sequences are permitted and represent
111 a cross between PDP-10 Macro SNOBOL (a.k.a. DECBOL), SITBOL and Catspaw
112 SPITBOL usage;
113 Exponentiation: ^ **
115 Alternation: | !
116 Unary negation: ~ \
117 Assignment: = _
118 Comment line: * # | ; !
119 Continuation line: + .
120 Both square brackets ([]) and angle brackets (<>) may be used to sub‐
122 script arrays and tables. The TAB (ASCII 9) character is accepted as
123 whitespace. Note that the use of the pound sign for comments allows
124 use of the shell interpreter sequence at the top of a file (ie;
125 "#!/usr/local/bin/snobol4 -b"). Underscore (_) and period (.) are
126 legal within identifiers and labels.
127 Extensions
130 ARRAY/TABLE access
131 Multiple ARRAY and/or TABLE index operations may appear in a
132 row, without having to resort to use of the ELEMENT function, so
133 long as no intervening spaces (or line continuations) appear.
134 BREAKX()
136 The BREAKX() function is a pattern function used for fast scan‐
137 ning. BREAKX(str) is equivalent to BREAK(str) ARBNO(LEN(1)
138 BREAK(str)). In other words BREAKX matches a sequence of ever
139 larger strings terminated by a break set. BREAKX can be used as
140 a faster matching replacement for ARB; BREAKX('S') 'STRING'
141 always runs faster than ARB 'STRING' since it only attempts
142 matching 'STRING' at locations where an 'S' has been detected.
143 Case folding
145 By default the compiler folds identifiers and directives to
146 upper case, so programs can be entered in either case. To dis‐
147 able case folding use the directive -CASE 0 or -CASE. To re-
148 enable case folding use directive -CASE n where n is a non-zero
149 integer. The status of case folding may be examined and con‐
150 trolled from a running program by the unprotected system keyword
151 &CASE.
152 CHAR()
154 The CHAR() function takes an integer from 0 to 255 and returns
155 the n'th character in &ALPHABET.
156 DATE() For compatibility with new versions of Catspaw SPITBOL DATE(0)
158 returns strings of the form MM/DD/YY HH:MM:SS, and DATE(2)
159 returns strings of the form YYYY-MM-YY HH:MM:SS. With any other
160 arguments DATE() returns strings of the form MM/DD/YYYY
161 HH:MM:SS.
162 -ERROR/-NOERRORS
164 Directives -ERROR and -NOERRORS control execution of program
165 with compiler errors. If the -ERROR directive is given, the
166 program will be executed (but any attempt to execute a statement
167 with a compiler error will cause a fatal execution error). By
168 default programs with compiler errors will not be started, this
169 can be restored using -NOERRORS.
170 &ERRTEXT
172 After an otherwise fatal error is curtailed due to a non-zero
173 value in &ERRLIMIT, the protected keyword &ERRTEXT will contain
174 the error message.
175 -EXECUTE/-NOEXECUTE
177 Directives -EXECUTE and -NOEXECUTE control execution of pro‐
178 grams. If the -NOEXECUTE directive is given, the program will
179 be not executed after compilation. -EXECUTE Cancels any previ‐
180 ous -NOEXECUTE.
181 FREEZE()/THAW()
183 The FREEZE() function prohibits creation of new entries in the
184 referenced table. This is useful once a table has been initial‐
185 ized to avoid creating empty entries on lookups that fail. This
186 can greatly improve program speed, since frozen tables will not
187 become clogged with empty entries. Lookups for uninitialized
188 entries will return the null string. Attempts to assign to a
189 non-existent entry will cause a “Variable not present where
190 required” error. The THAW() function restores normal entry cre‐
191 ation behavior.
192 FUNCTION()
194 The FUNCTION() predicate evaluates it's argument as a string
195 (with case folding), and returns the null string if a function
196 with that name exists and fails if it does not. The FUNCTION()
197 predicate exists in SITBOL.
198 >RACE
200 If set to a non-zero value, each time a garbage collection is
201 run, a trace message is output indicating the source file and
202 line number of the current statement, how long the GC took, and
203 how many units of storage are now free.
204 HOST()
206 A limited simulation of the SPITBOL HOST() function (with lib‐
207 eral implementation specific extensions) is included.
208 The -INCLUDE file host.sno contains symbolic defines for these
210 (and many other) function codes.
211 HOST() with no parameters returns a string describing the system
213 the program is running on. The string contains three parts,
214 separated by colons. The first part describes the physical
215 architecture, the second describes the operating system, and the
216 third describes the language implementation name. Example:
217 i386:Darwin 8.11.1:CSNOBOL4 1.2
218 HOST(0) returns a string containing the command line parameter
220 supplied to the -u option, if any. If no -u option was given,
221 HOST(0) returns the concatenation of all user parameters follow‐
222 ing the input filename(s).
223 HOST(1,string) passes the string to the system(3) c library
225 function, and returns the subprocess exit status.
226 HOST(2,n) for integer n returns the n'th command line argument
228 (regardless of whether the argument was the command name, an
229 option, a filename or a user parameter) as a string, or failure
230 if n is out of range.
231 HOST(3) returns an integer for use with HOST(2) indicating the
233 first command line argument available as a user parameter.
234 HOST(4,string) returns the value of the environment variable
236 named string.
237 -INCLUDE
239 The -INCLUDE directive causes the compiler to interpolate the
240 contents of the named file enclosed in single or double quotes.
241 Any filename will be included only once, this can be overridden
242 by appending a trailing space to the filename. Trailing spaces
243 are removed from the filename before use. If the file is not
244 found in the current working directory an attempt will be made
245 to find it in the directory specified by the SNOLIB environment
246 variable, or if that is not set, a predetermined library direc‐
247 tory.
248 -COPY is a synonym for -INCLUDE for compatibility with SPIT‐
250 BOL/370.
251 IO_FINDUNIT()
253 The IO_FINDUNIT() function returns an unused I/O unit number for
254 use with the INPUT() or OUTPUT() functions. IO_FINDUNIT() is
255 meant for use in subroutines which can be reused. IO_FINDUNIT()
256 will never return a unit number below 20.
257 LABEL()
259 The LABEL() predicate evaluates it's argument as a string (with
260 case folding), and returns the null string if a label with that
261 name has been defined, and fails if it does not. The LABEL()
262 predicate was copied from SITBOL and Steve Duff's version of
263 Macro SPITBOL.
264 >RACE
266 keyword enables Garbage Collection tracing if non-zero. If pos‐
267 itive, the value of >RACE will be decremented after it is
268 tested.
269 &LINE/&FILE/&LASTLINE/&LASTFILE
271 The &LINE and &FILE keywords can be used to determine the source
272 file and file line associated with the current statement. The
273 &LASTLINE and &LASTFILE return the source file and file line
274 associated with the previous statement.
275 -LINE
277 The -LINE directive can be used to alter SNOBOL's idea of the
278 current source file and line (ie; for use by preprocessors).
279 -LINE takes a line number and an optional quoted string file‐
280 name.
281 Lexical comparison
283 A full set of lexical (string) comparison predicates have been
284 added to complement the standard LGT() function; LEQ(), LGE(),
285 LLE(), LLT(), LNE().
286 LPAD()/RPAD()
288 The LPAD() and RPAD() functions take the first argument (sub‐
289 ject) string, and pad it out to the length specified in the sec‐
290 ond argument, using the first character of the optional third
291 argument. If the third argument is missing, or is the null
292 string, spaces will be used for padding. The subject will be
293 returned unmodified if already long enough.
294 Named files
296 Filenames can be supplied to the INPUT() and OUTPUT() functions
297 via an optional fourth argument. If the filename begins with a
298 vertical bar (|), the remainder is used as a shell command whose
299 stdin (in the case of OUTPUT()) or stdout (in the case of
300 INPUT()) will be connected to the file variable via a pipe. If
301 a pipe is opened by INPUT() input in "update" mode, the connec‐
302 tion will be bi-directional (on systems with socketpair and
303 Unix-domain sockets). The filename - (hyphen) is interpreted as
304 stdin on INPUT() and stdout on OUTPUT(). The magic filenames
305 /dev/stdin, /dev/stdout, and /dev/stderr refer to the current
306 process standard input, standard output and standard error I/O
307 streams respectively regardless of whether those special file‐
308 names exist on your system. The magic pathname /dev/fd/n, opens
309 a new I/O stream associated with file descriptor number n. The
310 magic pathname /tcp/hostname/service can be used to open connec‐
311 tion to a TCP server. If the path ends in the optional suffix
312 /priv the local address will be bound to a port number below
313 1024, if process privileges allow. /udp/hostname/service
314 behaves similarly for UDP. The magic pathname /dev/tmpfile
315 opens an anonymous temporary file for reading and writing, see
316 tmpfile(3). On VMS, Win32, and MS-DOS (when compiled with
317 DJGPP), the pathnames /dev/null and /dev/tty are magical, and
318 refer to the null device, and the user's terminal/console,
319 respectively.
320 ORD()
322 The ORD() function returns the ordinal value (zero to 255) of
323 the first character in it's string argument (the inverse of the
324 CHAR() function).
325 &PARM
327 The entire command line is available via the &PARM protected
328 keyword for compatibility with Catspaw SNOBOL4+. Use of the
329 SPITBOL compatible HOST() function is probably preferable.
330 REAL numbers in INTEGER contexts
332 REAL numbers (or strings convertible to REAL) are accepted in
333 all contexts which previously required an INTEGER (or string
334 convertible to INTEGER). Contexts include TABLE(), ITEM(),
335 array indices, INPUT(), OUTPUT(), SET(), keyword values, CHAR(),
336 RPAD(), LPAD(), FIELD(), COLLECT(), DUMP(), DUPL(), OPSYN(),
337 SUBSTR().
338 REVERSE()
340 REVERSE() returns it's subject string in reverse order.
341 Scientific notation
343 REAL number syntax has been expanded to allow exponents of the
344 form:
345 ANY('Ee') ('+' | '-' | '') SPAN('0123456789'). Exponential for‐
346 mat reals need not contain a decimal point.
347 SERV_LISTEN()
349 The SERV_LISTEN() function makes SNOBOL4 into a network server
350 process, and takes three STRING arguments: FAMILY, TYPE, SER‐
351 VICE. FAMILY must be either "inet" for an Internet Protocol v4
352 socket, "inet6" for an Internet Protocol v6 socket, or "unix"
353 for a local ("unix domain") socket. The second argument, TYPE
354 must be "stream", and the third argument, SERVICE must be a port
355 number or service name (for an internet socket), or a pathname
356 (for a "unix" socket). SERV_LISTEN() listens for incoming
357 requests, accepts them, then "forks" a child process and returns
358 an integer file descriptor which can be opened for bidirectional
359 I/O using a "/dev/fd/n" magic pathname. The original ("parent")
360 process never returns from the SERV_LISTEN() call. This func‐
361 tion is only available on systems with the "fork" system call,
362 which makes a child process which is an identical copy of the
363 parent process.
364 SET()
366 The SET() function can be used to seek the file pointer of an
367 open file. The first argument is an I/O unit number, the second
368 is an integer offset. The third argument, an integer determines
369 from whence the file pointer will be adjusted. If whence is
370 zero the starting point is the beginning of the file, if whence
371 is one, the starting point is the current file pointer, and if
372 whence is two, the starting point is the end of the file. SET()
373 returns the new file pointer value. On systems with 64-bit file
374 pointers and 32-bit integers (ie; 4.4BSD on i386) the return
375 value will be truncated to 32-bits, and only the first and last
376 4 gigabytes of a file can be accessed directly.
377 SITBOL file functions
379 FILE(string) is a predicate which returns the null string if
380 it's argument is the name of a file that exists, and fails if it
381 does not. DELETE(string) is a predicate which tries to remove
382 the file named by it's argument, and fails if it cannot.
383 RENAME(string1,string2) is a predicate which attempts to rename
384 the file named by string2 to the file named by string1. Unlike
385 the SITBOL version, if the target file exists, it will be
386 removed.
387 SNOBOL4+ real functions
389 EXP(), LOG() and CHOP() functions are available for compatibil‐
390 ity with SNOBOL4+. EXP() returns the value e ** x, LOG()
391 returns the natural logarithm of it's REAL argument, and CHOP()
392 truncates the fractional part of it's REAL argument (rounding
393 towards zero), and returns a REAL.
394 SORT()/RSORT()
396 The SORT() and RSORT() functions take two arguments. The first
397 can be either an array or a table. If the first argument is an
398 array, it may be singly-dimensioned in which case the second
399 argument, if non-null should indicate the name of a field of a
400 programmer defined data type to use to access the sort key.
401 Otherwise the first argument should be a table or a doubly-
402 dimensioned array, in which case the second argument may an
403 integer indicating the array column on which to sort. If the
404 second argument is null, it is taken to be 1. The array (or ta‐
405 ble) is not modified; a new array is allocated and returned.
406 SORT() sorts elements in ascending order, while RSORT() sorts in
407 descending order.
408 Example: for a table TAB of integers, indexed by strings being
410 used to tabulate word counts FREQ = RSORT(TAB,2) returns an
411 array such that FREQ<1,1> contains the most frequent word while
412 FREQ<1,2> contains the number of occurrences of that word.
413 While WORDS = SORT(TAB,1) returns an array with the rows by the
414 lexicographical ordering of the words; WORDS<1,1> contains the
415 lexicographically first word and WORDS<1,2> contains the number
416 of occurrences of that word.
417 SPITBOL operators
419 The SPITBOL scan (?) and assignment (=) operators have been
420 added. A pattern match can appear within an expression, and
421 returns the matched string as it's value. Similarly assignment
422 can appear in an expression, and returns the assigned value. An
423 assignment after a scan (ie; STRING ? PATTERN = VALUE) performs
424 a scan and replace. Assignment is right associative, and has
425 the lowest precedence, while scan is left associative and has a
426 precedence just higher than assignment.
427 The SPITBOL selection/alternative construction can be used in
429 any expression. It consists of a comma separated list of
430 expressions inside parentheses. The expressions are evaluated
431 until one succeeds, and it's value is returned. Abuse of this
432 construction may result in incomprehensible code.
433 The type NUMERIC with CONVERT() and the removal of leading spa‐
435 ces from strings converted to numbers (implicitly or explicitly)
436 are also legal when SPITBOL extensions are enabled. SPITBOL
437 extensions can be enabled and disabled using the -PLUSOPS direc‐
438 tive. -PLUSOPS 0 disables SPITBOL operators, while -PLUSOPS or
439 -PLUSOPS n where n is a non-zero integer enables them. SPITBOL
440 extensions are enabled by default.
441 SQRT()
443 The SQRT() function is available for compatibility with SPARC
444 SPITBOL. SQRT() fails if the argument is negative, but does not
445 cause a fatal error.
446 SSET()
448 Experimental "scaled set" function. Takes arguments unit, off‐
449 set, whence, and scale. The first three are analogous to the
450 same arguments for the SET() function. The last parameter is
451 used as a multiplicative scaling factor on the offset parameter,
452 and as a divisor on the return value. When used in combination
453 with relative SET() calls (whence of one), any file offset can
454 be achieved, even when system file offsets are larger than can
455 be represented in a SNOBOL4 INTEGER. Support for "Large Files"
456 is enabled when available, but not all file systems support
457 them.
458 SUBSTR()
460 SUBSTR() takes a subject string as it's first argument, and
461 returns the substring starting at the position specified by the
462 second argument (one-based) with a length specified by the third
463 argument. If the third argument is missing or zero, the remain‐
464 der of the string is returned.
465 TERMINAL I/O variable
467 The variable TERMINAL is associated with the standard error file
468 descriptor for both input and output.
469 Trig functions
471 SIN(), COS() and TAN() functions are available for compatibility
472 with SPARC SPITBOL and take arguments in radians.
473 &UCASE/&LCASE
475 Protected keywords &UCASE and &LCASE contain upper and lower
476 case characters respectively.
477 VDIFFER()
479 The VDIFFER() function takes two arguments, if they DIFFER(),
480 the first argument's value is returned. This is intended to be
481 used in contexts where DIFFER(X) X would otherwise have been
482 used. The VDIFFER() function was copied from Steve Duff's ver‐
483 sion of Macro SPITBOL.
484 I/O Associations
487 I/O is performed by associating a variable name with a numbered I/O
488 unit using the INPUT() and OUTPUT() functions. The following associa‐
489 tions are available by default;
490 Variable Unit Association
492 INPUT 5 standard input
493 OUTPUT 6 standard output
494 TERMINAL 7 standard error (output)
495 TERMINAL 8 /dev/tty (input)
496 I/O Options
499 The third argument of the INPUT() and OUTPUT() functions is interpreted
500 as a string of single letter options, commas are ignored. Some options
501 effect only the I/O variable named in the first argument, others effect
502 any variable associated with the unit number in the second argument.
503 digits A span of digits will set the input record length for the named
505 I/O variable. This controls the maximum string that will be
506 returned for regular text I/O, and the number of bytes returned
507 for binary I/O. Record length is per-variable; multiple vari‐
508 ables may be associated with the same unit, but with different
509 record lengths.
510 A For OUTPUT() the unit will be opened for append access (no-op
512 for INPUT()).
513 B The unit will be opened for binary access. On input newline
515 characters have no special meaning; the number of bytes trans‐
516 ferred depends on record length (see above). On output no new‐
517 line is appended. For terminal devices, all I/O to this unit
518 will be done without special processing for line editing or EOF,
519 while characters which deliver signals (interrupt, kill, sus‐
520 pend) are still processed. Units opened on the same terminal
521 device entry operate independently; some can use binary mode,
522 while others operate in text mode.
523 C Character at a time I/O. A synonym for B,1.
525 T Terminal mode. No newline characters are added on output, and
527 any newline characters are returned on input. Terminal mode
528 effects only the referenced unit. Terminal mode is useful for
529 outputting prompts in interactive programs.
530 Q Quiet mode. Turns off input echo on terminals. Effects only
532 input from this unit.
533 U Update mode. The unit is opened for both input and output.
535 W Unbuffered writes. Each output variable assignment causes an
537 I/O transfer to occur, rather than collecting the data in a buf‐
538 fer for efficiency.
539
542 -b Toggle startup banner output (by default on).
543 -d DDD Allocate “dynamic storage” region of DDD descriptors for pro‐
545 gram code and data. A suffix of k multiplies the number by
546 1024, a suffix of m multiplies the number by 1048576. A
547 larger dynamic region may result in fewer garbage collections
548 (storage regenerations), however large values may cause exe‐
549 cution to slow down when large amounts of garbage collect.
550 Most programs do not need an increased dynamic region to run.
551 If your program terminates with an “Insufficient storage to
552 continue” message you need to increase the dynamic storage
553 region size.
554 -f Toggle folding of identifiers to upper case (see -CASE and
556 &CASE).
557 -g Enable garbage collection tracing (sets >RACE to -1).
559 -h Give help. Shows usage message, includes default sizes for
561 “dynamic region” and pattern match stack.
562 -k Toggle running programs with compilation errors (see -ERROR
564 and -NOERRORS extensions). By default programs with compila‐
565 tion errors will not be run.
566 -l Re-enable listing to stdout. (default is -UNLIST). Default
568 listing side is LEFT.
569 -n Toggle running programs after compilation (see -EXECUTE and
571 -NOEXECUTE extensions). By default programs are run after
572 compilation.
573 -p Toggle SPITBOL extensions (also controlled by -PLUSOPS).
575 -r Toggle reading INPUT from input file(s) after END label.
577 Otherwise INPUT defaults (back) to standard input after pro‐
578 gram compilation is complete.
579 -s Toggle termination statistics (off by default).
581 -u params specifies a parameter string available via HOST(0).
583 -v Show version and exit.
585 -- Terminates processing items as options. Any remaining strings
587 are treated as files or user parameters.
588 -M Specifies that all items left on the command line after
590 option processing is complete are to be treated as filenames.
591 The files are read in turn until an END statement is found
592 (Any remaining data is available via the INPUT variable if
593 the -r option is also given). A -- terminates processing of
594 arguments as files, and makes the remaining arguments avail‐
595 able as user parameters (see the HOST() function).
596 -P DDD Allocate DDD descriptors for the pattern match stack. A suf‐
598 fix of k multiplies the number by 1024, a suffix of m multi‐
599 plies the number by 1048576. The pattern match stack is used
600 to save backtracking and conditional assignment information
601 during pattern matching. If your program terminates with an
602 “Overflow during pattern matching” message (Error 16) you
603 need to increase the pattern match stack size.
604 -S DDD Allocate DDD descriptors for the interpreter stack. A suffix
606 of k multiplies the number by 1024, a suffix of m multiplies
607 the number by 1048576. The interpreter stack is used for
608 saving data, and passing parameters to internal procedures.
609 If your program terminates with an “Stack overflow” message
610 (Error 21) you need to increase the interpreter stack size.
611 A common reason for needing additional stack space is for
612 tracing deeply nested DATA() structures during garbage col‐
613 lection.
614
617 snobol4dbm(3),snobol4tcl(3),snolib(3).
618 http://www.snobol4.org
621 All things SNOBOL4 related.
622 http://www.snobol4.com
625 Catspaw: commercial SPITBOL implementations, Free SNOBOL4+ for
626 DOS.
627 http://www.snobol4.org/doc/burks/tutorial/contents.htm
630 SNOBOL4 language tutorial (from Catspaw Vanilla SNOBOL4)
631 http://www.snobol4.org/doc/burks/manual/contents.htm
634 Catspaw Vanilla SNOBOL4 manual.
635 ftp://ftp.snobol4.com/spitman.pdf
638 Catspaw Macro SPITBOL manual
639 [1] R. E. Griswold, J. F. Poage, and I. P. Polonsky
642 The SNOBOL4 Programming Language, 2nd ed., Prentice-Hall Inc.,
643 1971.
644 Reference manual for Macro SNOBOL4. (soon to be available as a
645 PDF!!!)
646 [2] R. E. Griswold,
649 The Macro Implementation of SNOBOL4, W. H. Freeman and Co.,
650 1972.
651 Book describing the implementation techniques used in Macro
652 SNOBOL4.
653 ftp://ftp.snobol4.org/snobol/doc/
656 Directory with sources for University of Arizona SNOBOL4 memos,
657 including formatted versions of memo s4d58, which describes each
658 pseudo-instruction in the Snobol Implementation Language (SIL).
659
662 Philip L. Budne
663 with a little help from:
665 R. E. Griswold, J. F. Poage, and I. P. Polonsky
667 Mark Emmer (code from SNOBOL4+)
669 Viktors Berstis (code from Minnesota SNOBOL4)
671
674 “Insufficient storage to continue” (error 20)
675 “Dynamic” storage exhausted. See the -d option.
676 “Stack overflow” (error 21)
679 Interpreter stack exhausted. See the -S option.
680
683 I/O retains some record oriented flavor.
684 I/O is still tied to unit numbers.
686 “Dynamic” storage cannot be expanded after startup.
688 Integer math can never "fail", even on overflow.
690 Oversize integer constants may not be detected.
692Local 09 Dec 2008 SNOBOL4(1)