This chapter explains how to embed Molt in a Rust application. There are several parts to this:

• Creating a Molt interpreter
• Defining application-specific Molt commands
• Invoking the interpreter to evaluate Molt commands and scripts

An application may execute scripts for its own purposes and arbitrary scripts defined by the user. One common pattern is to define a shell application the user may use to execute their own scripts using the application-specific command set.

It is also possible to define Molt library crate that defines commands for installation into an interpreter.

The initial step, creating a Molt interpreter, is trivially easy:

# #![allow(unused_variables)]
#fn main() {
use molt::Interp;

let mut interp = Interp::new();

// Add application-specific commands
#}

This creates an interpreter containing the standard set of Molt commands. Alternatively, you can create a completely empty interpreter and add just the commands you want:

# #![allow(unused_variables)]
#fn main() {
use molt::Interp;

let mut interp = Interp::empty();

// Add application-specific commands
#}

This is useful if you wish to use the Molt interpreter as a safe file parser.

Eventually there will be an API for adding specific standard Molt commands back into an empty interpreter so that the application can create a custom command set (e.g., including variable access and control structures but excluding file I/O), but that hasn't yet been implemented.

We'll cover the remaining topics in the following sections.