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
46 option prevents that from happening making it useful for check‐
47 ing 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
54 either 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
98 error message will be shown and the user will be prompted for more
99 input.
100 Any objects left on the stack after a command will be printed and the
102 stack cleared. This makes interactive mode useful as a calculator,
103 e.g.,
104 slsh> 3*10;
106 30
107 slsh> x = [1:20];
108 slsh> sum (sin(x)-cos(x));
109 0.458613
110 slsh> quit;
111 Note that in this mode, variables are automatically declared.
112 The interactive mode also supports command logging. Logging is enabled
114 by the start_log function. The stop_log function will turn off log‐
115 ging. The default file where logging information will be written is
116 slsh.log. An alternative may be specified as an optional argument to
117 the start_log function:
118 slsh> start_log;
120 Logging input to slsh.log
121 .
122 .
123 slsh> stop_log;
124 slsh> start_log("foo.log");
125 Logging input to foo.log
126 .
127 .
128 slsh> stop_log;
129 slsh> start_log;
130 Logging input to foo.log
131 Similarly, the save_input function may be used to save the previous
133 input to a specified file:
134 slsh> save_input;
136 Input saved to slsh.log
137 slsh> save_input ("foo.log");
138 Input saved to foo.log
139 As the above examples indicate, lines must end in a semicolon. This is
141 a basic feature of the language and permits commands to span multiple
142 lines, e.g.,
143 slsh> x = [
145 1,2,3,
146 4,5,6];
147 slsh> sum(x);
148 For convenience some users prefer that commands be automatically termi‐
149 nated with a semicolon. To have a semicolon silently appended to the
150 end of an input line, put the following in $HOME/.slshrc file:
151 #ifdef __INTERACTIVE__
153 slsh_append_semicolon (1);
154 #endif
155 The interactive mode also supports shell escapes. To pass a command to
157 the shell, prefix it with !, e.g.,
158 slsh> !pwd
160 /grandpa/d1/src/slang2/slsh
161 slsh> !cd doc/tm
162 slsh> !pwd
163 /grandpa/d1/src/slang2/slsh/doc/tm
164 Finally, the interactive mode supports a help and apropos function:
166 slsh> apropos list
168 apropos list ==>
169 List_Type
170 list_append
171 list_delete
172 .
173 .
174 slsh> help list_append
175 list_append
176 SYNOPSIS
178 Append an object to a list
179 USAGE
181 list_append (List_Type, object, Int_Type nth)
182 .
183 .
184 For convenience, the help and apropos functions do not require the syn‐
185 tactic constraints of the other functions.
186
188 By default, slsh is built to use the S-Lang readline interface, which
189 includes a customizable command completion and a history mechanism.
190 When slsh (or any S-Lang application that makes use of this feature)
191 starts in interactive mode, it will look for a file in the user's home
192 directory called .slrlinerc and load it if present. This file allows
193 the user to customize the readline interface and enable the history to
194 be saved between sessions. As an example, here is a version of the
195 author's .slrlinerc file:
196 % Load some basic functions that implement the history mechanism
198 () = evalfile ("rline/slrline.rc");
199 % The name of the history file -- expands to .slsh_hist for slsh
200 RLine_History_File = "$HOME/.${name}_hist";
201 % Some addition keybindings. Some of these functions are defined
203 % in rline/editfuns.sl, loaded by rline/slrline.rc
204 rline_unsetkey ("^K");
205 rline_setkey ("bol", "^B");
206 rline_setkey ("eol", "^E");
207 rline_setkey (&rline_kill_eol, "^L");
208 rline_setkey (&rline_set_mark, "^K^B");
209 rline_setkey (&rline_copy_region, "^Kk");
210 rline_setkey (&rline_kill_region, "^K^V");
211 rline_setkey (&rline_yank, "^K^P");
212 rline_setkey ("redraw", "^R");
213 #ifexists rline_up_hist_search
215 % Map the up/down arrow to the history search mechanism
216 rline_setkey (&rline_up_hist_search, "\e[A");
217 rline_setkey (&rline_down_hist_search, "\e[B");
218 #endif
219 #ifexists rline_edit_history
221 rline_setkey (&rline_edit_history, "^Kj");
222 #endif
223 % Add a new function
225 private define double_line ()
226 {
227 variable p = rline_get_point ();
228 variable line = rline_get_line ();
229 rline_eol ();
230 variable pend = rline_get_point ();
231 rline_ins (line);
232 rline_set_point (pend + p);
233 }
234 rline_setkey (&double_line, "^K^L");
235
237 Several useful example scripts are located in $pre‐
238 fix/share/slsh/scripts/, where $prefix represents the slsh installation
239 prefix (/usr, /usr/local,...). These scripts include:
240 sldb A script that runs the S-Lang debugger.
242 jpegsize
244 Reports the size of a jpeg file.
245 svnsh A shell for browsing an SVN repository.
247
249 The principal author of slsh is John E. Davis <www.jedsoft.org>. The
250 interactive mode was provided by Mike Noble. The S-Lang library upon
251 which slsh is based is primarily the work of John E. Davis with help
252 from many others.
253 This manual page was originally written by Rafael Laboissiere for the
255 Debian system (but may be used by others).
256 Permission is granted to copy, distribute and/or modify this document
258 under the terms of the GNU General Public License, Version 2 any later
259 version published by the Free Software Foundation.
260 On Debian systems, the complete text of the GNU General Public License
262 can be found in /usr/share/common-licenses/GPL
263 04 March 2018 SLSH(1)