The language and its implementation are described in [Griswold1971] and [Griswold1972].
For command line options see snobol4cmd(1).
Extensions from Catspaw SNOBOL4+, SPITBOL and SITBOL have been added, see snobol4ext(1).
Includes BLOCKS (SNOBOL4B) extensions, see snobol4blocks(1).
On ASCII-based systems, any character with the 8th bit set is treated as “alphabetic”, and can start, or be used in identifiers and labels. This includes characters from the “upper half” of national character sets and all bytes resulting from the UTF-8 encoding of Unicode characters. Include file utf.sno implements pattern matching functions for UTF-8 sequences.
Programs may be entered in mixed case; By default lower case identifiers are folded to upper case (see &CASE and –CASE). Case folding is performed by using the C library islower(3) test, and then using toupper(3) to convert the lower-case characters to upper case. When using UTF-8 encoded characters in code, case folding should be disabled, to prevent any bytes which appear to be lower case in the current locale from being modified.
The following operator character sequences are permitted and represent a cross between PDP-10 Macro SNOBOL, SITBOL and Catspaw SPITBOL usage:
| Assignment: | = _ |
| Comment line: | * # | ; ! |
| Continuation line: | + . |
Both square brackets ([]) and angle brackets (<>) may be used to subscript arrays and tables. The TAB (ASCII 9) character is accepted as whitespace.
Underscore (_) and period (.) are legal within identifiers and labels.
Note that the use of the pound sign for comments allows use of the script interpreter (hash-bang) sequence at the top of a file marked as executable: “#!/usr/local/bin/snobol4” or “#!/usr/bin/env snobol4”
See snobol4op(1) for operators.
1. The current working directory (“.”).
2. Any directories specified on the command line using -I options, in the order specified.
3a. Directories from the the SNOPATH environment variable (see below), if defined.
3b. If SNOPATH is not defined, the SNOLIB environment variable (or a compiled in default) is used as base to add the following directories:
The LOAD() function will also check for the file in shared subdirectory in each directory in the search path.
| sdb(1) | SNOBOL4 Debugger |
| snobol4cmd(1) | command line options |
| snobol4ctrl(1) | control lines |
| snobol4error(1) | &ERRTYPE and &ERRTEXT values |
| snobol4ext(1) | extensions to BTL SNOBOL4 |
| snobol4func(1) | built-in function list |
| snobol4io(1) | input/output |
| snobol4key(1) | keywords |
| snobol4op(1) | operators |
| snobol4blocks(1) | SNOBOL4B BLOCKS extension |
| snopea(1) | convert snopea documentation to roff and HTML |
| snobol4dirs(3) | directory access functions |
| snobol4ezio(3) | easy to use file I/O |
| snobol4ffi(3) | Foreign Function Interface functions |
| snobol4fork(3) | subprocess interface functions |
| snobol4host(3) | HOST and O/S functions |
| snobol4logic(3) | bit logic & formatting functions |
| snobol4load(3) | loading extension modules into SNOBOL4 |
| snobol4ndbm(3) | keyed file access functions |
| snobol4random(3) | pseudo-random numbers functions |
| snobol4readline(3) | input with line editing |
| snobol4setup(3) | loadable module builder |
| snobol4sprintf(3) | formatting function |
| snobol4sqlite3(3) | SQLite database interface functions |
| snobol4sqlite3dbm(3) | DBM interface using SQLite |
| snobol4stat(3) | file metadata functions |
| snobol4stcl(3) | Tcl/Tk interface functions |
| snobol4time(3) | date/time functions |
| snolib(3) | misc library functions |
| snopea(7) | A little “Plain Old Documentation” format for SNOBOL4 |
Philip. L. Budne (CSNOBOL4)
Mark Emmer (code from SNOBOL4+)
Viktors Berstis (code from Minnesota SNOBOL4)
James F. Gimpel (SNOBOL4B)
I/O retains some record oriented flavor (maximum line length on input).
“Dynamic” storage cannot be expanded after startup.
Integer math can never fail, even on overflow.
Oversize integer constants may not be detected.