User Commands SLSH(1)
NAME
slsh - Interpreter for S-Lang scripts
SYNOPSIS
slsh [ --help ] [ --version ] [ -g ] [ -n ] [ --init file ]
[ --no-readline ] [ -e string ] [ -i ] [ -q, --quiet ] [ -t
] [ -v ] [ -|script-file args... ]
DESCRIPTION
slsh is a simple program for interpreting S-Lang scripts.
It supports dynamic loading of S-Lang modules and includes a
readline interface for interactive use.
OPTIONS
--help
Show a summary of options
--version
Show slsh version information
-g Compile with debugging code, tracebacks, etc
-n Don't load the personal initialization file
--init file
Use this file instead of ~/.slshrc
--no-readline
Do not use a readline interface for the interactive
mode
-e string
Execute ``string'' as S-Lang code.
-i Force interactive mode. Normally slsh will go into
interactive mode if both stdin and stdout are attached
to a terminal.
-q, --quiet
Startup quietly by not printing the version and copy-
right information.
-t Normally, slsh will call slsh_main if it is defined.
This option prevents that from happening making it use-
ful for checking for syntax error.
-v Show verbose loading messages. This is useful for see-
ing what files are being loaded.
INITIALIZATION
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Upon startup, the program will try to load slsh.rc as fol-
lows. If either SLSH_CONF_DIR or SLSH_LIB_DIR environment
variables exist, then slsh will look look in the correspond-
ing directories for slsh.rc. Otherwise it will look in:
$(prefix)/etc/ (as specified in the Makefile)
/usr/local/etc/
/usr/local/etc/slsh/
/etc/
/etc/slsh/
The slsh.rc file may load other files from slsh's library
directory in the manner described below.
Once slsh.rc has been loaded, slsh will load $HOME/.slshrc
if present. Finally, it will load the script specified on
the command line. If the name of the script is -, then it
will be read from stdin. If the script name is not present,
or a string to execute was not specified using the -e
option, then slsh will go into interactive mode and read
input from the terminal. If the script is present and
defines a function called slsh_main, that function will be
called.
LOADING FILES
When a script loads a file via the built-in evalfile func-
tion or the require function (autoloaded by slsh.rc), the
file is searched for along the SLSH_PATH as specified in the
Makefile. An alternate path may be specified by the
SLSH_PATH environment variable.
The search path may be queried and set during run time via
the get_slang_load_path and set_slang_load_path functions,
e.g.,
set_slang_load_path ("/home/bill/lib/slsh:/usr/share/slsh");
INTERACTIVE MODE
When slsh is invoked without a script or is given the -i
command line argument, it will go into into interactive
mode. In this mode, the user will be prompted for input.
The program will leave this mode and exit if it sees an EOF
(Ctrl-D) or the user exits by issuing the quit command.
If an uncaught exception occurs during execution of a com-
mand, the error message will be shown and the user will be
prompted for more input.
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Any objects left on the stack after a command will be
printed and the stack cleared. This makes interactive mode
useful as a calculator, e.g.,
slsh> 3*10;
30
slsh> x = [1:20];
slsh> sum (sin(x)-cos(x));
0.458613
slsh> quit;
Note that in this mode, variables are automatically
declared.
The interactive mode also supports command logging. Logging
is enabled by the start_log function. The stop_log function
will turn off logging. The default file where logging
information will be written is slsh.log. An alternative may
be specified as an optional argument to the start_log func-
tion:
slsh> start_log;
Logging input to slsh.log
.
.
slsh> stop_log;
slsh> start_log("foo.log");
Logging input to foo.log
.
.
slsh> stop_log;
slsh> start_log;
Logging input to foo.log
Similarly, the save_input function may be used to save the
previous input to a specified file:
slsh> save_input;
Input saved to slsh.log
slsh> save_input ("foo.log");
Input saved to foo.log
As the above examples indicate, lines must end in a semi-
colon. This is a basic feature of the language and permits
commands to span multiple lines, e.g.,
slsh> x = [
1,2,3,
4,5,6];
slsh> sum(x);
For convenience some users prefer that commands be automati-
cally terminated with a semicolon. To have a semicolon
silently appended to the end of an input line, put the
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following in $HOME/.slshrc file:
#ifdef __INTERACTIVE__
slsh_append_semicolon (1);
#endif
The interactive mode also supports shell escapes. To pass a
command to the shell, prefix it with !, e.g.,
slsh> !pwd
/grandpa/d1/src/slang2/slsh
slsh> !cd doc/tm
slsh> !pwd
/grandpa/d1/src/slang2/slsh/doc/tm
Finally, the interactive mode supports a help and apropos
function:
slsh> apropos list
apropos list ==>
List_Type
list_append
list_delete
.
.
slsh> help list_append
list_append
SYNOPSIS
Append an object to a list
USAGE
list_append (List_Type, object, Int_Type nth)
.
.
For convenience, the help and apropos functions do not
require the syntactic constraints of the other functions.
READLINE HISTORY MECHANISM
By default, slsh is built to use the S-Lang readline inter-
face, which includes a customizable command completion and a
history mechanism. When slsh (or any S-Lang application
that makes use of this feature) starts in interactive mode,
it will look for a file in the user's home directory called
.slrlinerc and load it if present. This file allows the
user to customize the readline interface and enable the his-
tory to be saved between sessions. As an example, here is a
version of the author's .slrlinerc file:
% Load some basic functions that implement the history mechanism
() = evalfile ("rline/slrline.rc");
% The name of the history file -- expands to .slsh_hist for slsh
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RLine_History_File = "$HOME/.${name}_hist";
% Some addition keybindings. Some of these functions are defined
% in rline/editfuns.sl, loaded by rline/slrline.rc
rline_unsetkey ("^K");
rline_setkey ("bol", "^B");
rline_setkey ("eol", "^E");
rline_setkey (&rline_kill_eol, "^L");
rline_setkey (&rline_set_mark, "^K^B");
rline_setkey (&rline_copy_region, "^Kk");
rline_setkey (&rline_kill_region, "^K^V");
rline_setkey (&rline_yank, "^K^P");
rline_setkey ("redraw", "^R");
% Add a new function
private define double_line ()
{
variable p = rline_get_point ();
variable line = rline_get_line ();
rline_eol ();
variable pend = rline_get_point ();
rline_ins (line);
rline_set_point (pend + p);
}
rline_setkey (&double_line, "^K^L");
MISCELLANEOUS SCRIPTS
Several useful example scripts are located in
$prefix/share/slsh/scripts/, where $prefix represents the
slsh installation prefix (/usr, /usr/local,...). These
scripts include:
sldb A script that runs the S-Lang debugger.
jpegsize
Reports the size of a jpeg file.
svnsh
A shell for browsing an SVN repository.
AUTHOR
The principal author of slsh is John E. Davis
. The interactive mode was provided by
Mike Noble . The S-Lang library upon
which slsh is based is primarily the work of John E. Davis
with help from many others.
This manual page was originally written by Rafael Labois-
siere for the Debian system (but may be
used by others).
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Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU General Public License,
Version 2 any later version published by the Free Software
Foundation.
On Debian systems, the complete text of the GNU General Pub-
lic License can be found in /usr/share/common-licenses/GPL
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
_______________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE|
|____________________|__________________|_
| Availability | library/slang |
|____________________|__________________|_
| Interface Stability| Volatile |
|____________________|_________________|
NOTES
Source for slang is available on http://opensolaris.org.
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