


SLSH(1)                                                   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 copyright infor-
              mation.

       -t     Normally,  slsh  will  call  slsh_main  if  it is defined.  This
              option prevents that from happening making it useful for  check-
              ing for syntax error.

       -v     Show  verbose  loading messages.  This is useful for seeing what
              files are being loaded.

INITIALIZATION
       Upon startup, the program will try  to  load  slsh.rc  as  follows.  If
       either  SLSH_CONF_DIR or SLSH_LIB_DIR environment variables exist, then
       slsh will look look in the corresponding directories for slsh.rc.  Oth-
       erwise it will look in:

       $(prefix)/etc/   (as specified in the Makefile)



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SLSH(1)                                                   SLSH(1)


       /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 func-
       tion called slsh_main, that function will be called.

LOADING FILES
       When a script loads a file via the built-in evalfile  function  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  command,  the
       error  message  will  be  shown  and the user will be prompted for more
       input.

       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



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SLSH(1)                                                   SLSH(1)


       by  the  start_log  function.  The stop_log function will turn off log-
       ging.  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 function:

            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 semicolon.  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 automatically termi-
       nated with a semicolon.  To have a semicolon silently appended  to  the
       end of an input line, put the 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



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SLSH(1)                                                   SLSH(1)


           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 syn-
       tactic constraints of the other functions.

READLINE HISTORY MECHANISM
       By  default,  slsh is built to use the S-Lang readline interface, 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 history  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
            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);



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SLSH(1)                                                   SLSH(1)


               rline_set_point (pend + p);
            }
           rline_setkey (&double_line,  "^K^L");

MISCELLANEOUS SCRIPTS
       Several   useful    example    scripts    are    located    in    $pre-
       fix/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  <jed@jedsoft.org>.   The
       interactive  mode  was  provided  by Mike Noble <mnoble@space.mit.edu>.
       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  Laboissiere
       <rafael@debian.org> for the Debian system (but may be used by  others).

       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 Public License
       can be found in /usr/share/common-licenses/GPL


























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