The molt shell command invokes the Molt interpreter.

When called without any arguments, the command invokes the interactive interpreter:

$ molt shell
Molt 0.3.0
%

Molt commands may be entered at the % prompt. Enter exit to leave the interpreter.

When called with arguments, the first argument is presumed to be the name of a Molt script; any subsequent arguments are passed to the script.

$ molt shell my_script.tcl arg1 arg2 arg3
...
$

When called in this way, the variable arg0 contains the name of the script, and the variable argv contains a list of the additional arguments (if any).

For example, consider the following script, args.tcl:

puts "arg0 = $arg0"
puts "argv = $argv"

This script may be run as follows

$ molt shell args.tcl a b c
arg0 = args.tcl
argv = a b c
$

The molt shell and its underlying method, molt_shell::repl, support interactive prompts via the tcl_prompt1 variable. If defined, tcl_prompt1 should be a script; its value will be output as the prompt.

$ molt shell
% set count 0
% set tcl_prompt1 {return "[incr count]> "}
return "[incr count]> "
1> puts "Howdy!"
Howdy!
2>

This is slightly different than in Standard TCL, where the tcl_prompt1 script is intended to output the prompt rather than return it.

The Standard TCL shell, tclsh, provides a number of features that Molt currently does not.

• A .tclshrc file for initializing interactive shells.

  • A similar file will be added in the future.

• An option to execute a script and then start the interactive shell.

  • This can be added if there is demand.

• Environment variables for locating the interpreter's library of TCL code, locally installed TCL packages, etc.

  • Molt's library of TCL code is compiled into the interpreter, rather than being loaded from disk at run-time.
  • At present, Molt has no support for externally-defined TCL packages (other than the source command).