1SLSH(1) SLSH(1)
2
6 slsh - Interpreter for S-Lang scripts
7
9 slsh [ --help ] [ --version ] [ -g ] [ -n ] [ --init file ] [ --no-
10 readline ] [ -e string ] [ -i ] [ -q, --quiet ] [ -t ] [ -v ] [
11 -|script-file args... ]
12
15 slsh is a simple program for interpreting S-Lang scripts. It supports
16 dynamic loading of S-Lang modules and includes a readline interface for
17 interactive use.
18
20 --help Show a summary of options
21 --version
23 Show slsh version information
24 -g Compile with debugging code, tracebacks, etc
26 -n Don't load the personal initialization file
28 --init file
30 Use this file instead of ~/.slshrc
31 --no-readline
33 Do not use a readline interface for the interactive mode
34 -e string
36 Execute ``string'' as S-Lang code.
37 -i Force interactive mode. Normally slsh will go into interactive
39 mode if both stdin and stdout are attached to a terminal.
40 -q, --quiet
42 Startup quietly by not printing the version and copyright infor‐
43 mation.
44 -t Normally, slsh will call slsh_main if it is defined. This op‐
46 tion prevents that from happening making it useful for checking
47 for syntax error.
48 -v Show verbose loading messages. This is useful for seeing what
50 files are being loaded.
51
53 Upon startup, the program will try to load slsh.rc as follows. If ei‐
54 ther SLSH_CONF_DIR or SLSH_LIB_DIR environment variables exist, then
55 slsh will look look in the corresponding directories for slsh.rc. Oth‐
56 erwise it will look in:
57 $(prefix)/etc/ (as specified in the Makefile)
59 /usr/local/etc/
61 /usr/local/etc/slsh/
63 /etc/
65 /etc/slsh/
67 The slsh.rc file may load other files from slsh's library directory in
69 the manner described below.
70 Once slsh.rc has been loaded, slsh will load $HOME/.slshrc if present.
72 Finally, it will load the script specified on the command line. If the
73 name of the script is -, then it will be read from stdin. If the
74 script name is not present, or a string to execute was not specified
75 using the -e option, then slsh will go into interactive mode and read
76 input from the terminal. If the script is present and defines a func‐
77 tion called slsh_main, that function will be called.
78
80 When a script loads a file via the built-in evalfile function or the
81 require function (autoloaded by slsh.rc), the file is searched for
82 along the SLSH_PATH as specified in the Makefile. An alternate path
83 may be specified by the SLSH_PATH environment variable.
84 The search path may be queried and set during run time via the
86 get_slang_load_path and set_slang_load_path functions, e.g.,
87 set_slang_load_path ("/home/bill/lib/slsh:/usr/share/slsh");
89
91 When slsh is invoked without a script or is given the -i command line
92 argument, it will go into into interactive mode. In this mode, the
93 user will be prompted for input. The program will leave this mode and
94 exit if it sees an EOF (Ctrl-D) or the user exits by issuing the quit
95 command.
96 If an uncaught exception occurs during execution of a command, the er‐
98 ror message will be shown and the user will be prompted for more input.
99 Any objects left on the stack after a command will be printed and the
101 stack cleared. This makes interactive mode useful as a calculator,
102 e.g.,
103 slsh> 3*10;
105 30
106 slsh> x = [1:20];
107 slsh> sum (sin(x)-cos(x));
108 0.458613
109 slsh> quit;
110 Note that in this mode, variables are automatically declared.
111 The interactive mode also supports command logging. Logging is enabled
113 by the start_log function. The stop_log function will turn off log‐
114 ging. The default file where logging information will be written is
115 slsh.log. An alternative may be specified as an optional argument to
116 the start_log function:
117 slsh> start_log;
119 Logging input to slsh.log
120 .
121 .
122 slsh> stop_log;
123 slsh> start_log("foo.log");
124 Logging input to foo.log
125 .
126 .
127 slsh> stop_log;
128 slsh> start_log;
129 Logging input to foo.log
130 Similarly, the save_input function may be used to save the previous in‐
132 put to a specified file:
133 slsh> save_input;
135 Input saved to slsh.log
136 slsh> save_input ("foo.log");
137 Input saved to foo.log
138 As the above examples indicate, lines must end in a semicolon. This is
140 a basic feature of the language and permits commands to span multiple
141 lines, e.g.,
142 slsh> x = [
144 1,2,3,
145 4,5,6];
146 slsh> sum(x);
147 For convenience some users prefer that commands be automatically termi‐
148 nated with a semicolon. To have a semicolon silently appended to the
149 end of an input line, put the following in $HOME/.slshrc file:
150 #ifdef __INTERACTIVE__
152 slsh_append_semicolon (1);
153 #endif
154 The interactive mode also supports shell escapes. To pass a command to
156 the shell, prefix it with !, e.g.,
157 slsh> !pwd
159 /grandpa/d1/src/slang2/slsh
160 slsh> !cd doc/tm
161 slsh> !pwd
162 /grandpa/d1/src/slang2/slsh/doc/tm
163 Finally, the interactive mode supports a help and apropos function:
165 slsh> apropos list
167 apropos list ==>
168 List_Type
169 list_append
170 list_delete
171 .
172 .
173 slsh> help list_append
174 list_append
175 SYNOPSIS
177 Append an object to a list
178 USAGE
180 list_append (List_Type, object, Int_Type nth)
181 .
182 .
183 For convenience, the help and apropos functions do not require the syn‐
184 tactic constraints of the other functions.
185
187 By default, slsh is built to use the S-Lang readline interface, which
188 includes a customizable command completion and a history mechanism.
189 When slsh (or any S-Lang application that makes use of this feature)
190 starts in interactive mode, it will look for a file in the user's home
191 directory called .slrlinerc and load it if present. This file allows
192 the user to customize the readline interface and enable the history to
193 be saved between sessions. As an example, here is a version of the au‐
194 thor's .slrlinerc file:
195 % Load some basic functions that implement the history mechanism
197 () = evalfile ("rline/slrline.rc");
198 % The name of the history file -- expands to .slsh_hist for slsh
199 RLine_History_File = "$HOME/.${name}_hist";
200 % Some addition keybindings. Some of these functions are defined
202 % in rline/editfuns.sl, loaded by rline/slrline.rc
203 rline_unsetkey ("^K");
204 rline_setkey ("bol", "^B");
205 rline_setkey ("eol", "^E");
206 rline_setkey (&rline_kill_eol, "^L");
207 rline_setkey (&rline_set_mark, "^K^B");
208 rline_setkey (&rline_copy_region, "^Kk");
209 rline_setkey (&rline_kill_region, "^K^V");
210 rline_setkey (&rline_yank, "^K^P");
211 rline_setkey ("redraw", "^R");
212 #ifexists rline_up_hist_search
214 % Map the up/down arrow to the history search mechanism
215 rline_setkey (&rline_up_hist_search, "\e[A");
216 rline_setkey (&rline_down_hist_search, "\e[B");
217 #endif
218 #ifexists rline_edit_history
220 rline_setkey (&rline_edit_history, "^Kj");
221 #endif
222 % Add a new function
224 private define double_line ()
225 {
226 variable p = rline_get_point ();
227 variable line = rline_get_line ();
228 rline_eol ();
229 variable pend = rline_get_point ();
230 rline_ins (line);
231 rline_set_point (pend + p);
232 }
233 rline_setkey (&double_line, "^K^L");
234
236 Several useful example scripts are located in $pre‐
237 fix/share/slsh/scripts/, where $prefix represents the slsh installation
238 prefix (/usr, /usr/local,...). These scripts include:
239 sldb A script that runs the S-Lang debugger.
241 jpegsize
243 Reports the size of a jpeg file.
244 svnsh A shell for browsing an SVN repository.
246
248 The principal author of slsh is John E. Davis <www.jedsoft.org>. The
249 interactive mode was provided by Mike Noble. The S-Lang library upon
250 which slsh is based is primarily the work of John E. Davis with help
251 from many others.
252 This manual page was originally written by Rafael Laboissiere for the
254 Debian system (but may be used by others).
255 Permission is granted to copy, distribute and/or modify this document
257 under the terms of the GNU General Public License, Version 2 any later
258 version published by the Free Software Foundation.
259 On Debian systems, the complete text of the GNU General Public License
261 can be found in /usr/share/common-licenses/GPL
262 19 February 2021 SLSH(1)