toy-interpreter

Simple programming language interpreter written in Rust, brought to your browser using Sapper and WebAssembly 🚀

The language

The purpose of designing this language was learning about compilers and Rust. Consider it a toy.

Features:

• variables

a = 5
b = a + 1

• math expressions

2 + 2
9 - 2 * 3
(9 - 2) * 3

• functions

fun sum(a, b) = a + b
fun sub(a, b) = sum(a, -b)

• conditional expressions

2 ? 3 : 4       // 3, positive values considered truthy
0 ? 3 : 4       // 4

fun min(a, b) = a - b ? b : a

• support for recurrence

fun factorial(n) = n ? n * factorial(n - 1) : 1
fun fibonacci(n) = n ? (n - 1 ? fibonacci(n - 1) + fibonacci(n - 2) : 1) : 0

Feel free to give it a go at https://grzegorzkazana.github.io/toy-interpreter/.

Tools

• Rust compiled to WebAssembly using wasm-pack.
• Sapper - server-side Svelte framework used for exporting static html (SSG)
• Typescript
• testing:
  • Rust: native cargo test
  • js/ts: jest + puppeteer for simple e2e

How to run

Prerequisites: node, cargo and wasm-pack.

Running the console version of interpreter:

cd interpreter
cargo run

Building the wasm binary:

make build-interpreter

Building the website:

make build-frontend

Running tests:

make test-all

To run frontend dev server (make sure you have built wasm binary prior to this step!):

cd frontend
npm run dev