monkey-interpreter

An interpreter for the monkey programming language written in Rust without external dependencies/crates. The content of this repository is based on the book Writing an Interpreter in Go by Thorsten Ball, but instead of implenting it in Go, I've decided to use Rust for the following reasons:

• Rust has sum types, which remove the need of interfaces and dynamic dispatch as shown in the book
• Rust has pattern matching, which makes the code more concise and readable
• Rust can compile to WebAssembly, which makes it possible to run the interpreter in the browser (which I used to create a small demo)
• Rust has a great testing framework, which makes it easy to write unit tests
• Lastly, I love Rust 🦀

Usage

WebAssembly

The interpreter can also be compiled to WebAssembly, which makes it possible to run it in the browser. A small demo is available at https://monkey-interpreter.jeaurond.dev/.

You can install the npm package @benjeau/monkey-interpreter by running the following command:

npm install @benjeau/monkey-interpreter

Then, you can use the interpreter in your TypeScript/JavaScript code like this:

import { execute, lexer } from '@benjeau/monkey-interpreter';

const program = `
let add = fn(x, y) {
    x + y;
};

let result = add(5, 10);
`;

const tokens = lexer(program); // Returns an array of tokens
const result = execute(program); // Returns the result of the program

For more details, please refer to the types from within the package.

Compilation

To compile the interpreter to WebAssembly, you need to install wasm-pack and run the following command:

wasm-pack build --target bundler

This will generate a pkg directory with the compiled WebAssembly files.

Rust

To install and use the interpreter, you can use the following command after cloning the repository:

cargo run

This will start the REPL, where you can enter your code and see the output.