molt-sample: A sample Molt extension

This repo shows how to create a basic Molt shell application using the molt and molt-shell crates, including how to extend the shell with Molt commands and how to define Molt extension crates. For more information, see the rustdocs and The Molt Book.

Feel free to fork this repo as the basis for new Molt shell applications and extension crates.

Structure

The file src/main.rs creates a Molt interpreter and extends it with a command, square, that computes the square of an integer.

It also installs the molt_sample:: extension crate, which is defined in src/lib.rs. The sample extension defines two Molt commands. double doubles an integer value, and is defined in Rust; triple triples an integer value, and is defined in src/lib.tcl.

Thus, this sample can be used as a standalone application; but it can also be used a dependency for another Rust project and its commands installed into that project's interpreter.

Running the REPL

The following assume that Rust and Cargo are installed.

To run an interactive REPL:

$ cargo run
   Compiling molt-sample v0.3.0 (/Users/will/github/molt-sample)
    Finished dev [unoptimized + debuginfo] target(s) in 0.54s
     Running `target/debug/molt-sample`
% square 2
4
% exit
$

To run a script:

$ cargo run sample.tcl
   Compiling molt-sample v0.3.0 (/Users/will/github/molt-sample)
    Finished dev [unoptimized + debuginfo] target(s) in 0.54s
     Running `target/debug/molt-sample sample.tcl`
In sample.tcl
The square of 3 is 9.
$

To run the script from inside the REPL:

$ cargo run
   Compiling molt-sample v0.3.0 (/Users/will/github/molt-sample)
    Finished dev [unoptimized + debuginfo] target(s) in 0.54s
     Running `target/debug/molt-sample`
% source sample.tcl
In sample.tcl
The square of 3 is 9.
%