README.md

Monkey

Yet another Monkey interpreter & compiler implementation in Rust, based on Thorsten Ball's Writing An Interpreter In Go and Writing A Compiler In Go books.

Features

• AST
• Tokenizer
• Parser
• Lexer
• Evaluator
• Compiler
• SymbolTable
• VirtualMachine
• Builtin Functions
• Functions & Closures
• Read–Eval–Print Loop

Usage

1. Install rustup

2. Test

$ cargo test --all

3. Run

$ cargo run --bin monkey

Monkey Compiler v0.2.0
>>> "Hello, " + "World!"
Hello, World!
>>>

Examples

Functions

[1, 2 * 2, 3 + 3]

Function Call

let identity = fn(x) { x; }; identity(7); //7

let add = fn(a, b) { a + b }; 
let sub = fn(a, b) { a - b }; 
let applyFunc = fn(a, b, func) { 
    func(a, b) 
}; 
applyFunc(10, 2, sub); //8

If

if (x < y) { z } else { w }

Nested If

if (2 > 1) { if (3 > 1) { return 7; } return 0; }

HashMap

{"one": 0 + 1, "two": 10 - 8, "ten": 50 / 5}

Arrays

let arr = [1, 2 * 2, 3 + 3] //arr[1 + 1] => returns 6

Operator Precedence

3 + 4 * 5 == 3 * 1 + 4 * 5 //((3 + (4 * 5)) == ((3 * 1) + (4 * 5)))

Error Handlers

if (10 > 1) { if (10 > 1) { return true + false; } return 1; } //unknown operator: BOOLEAN + BOOLEAN

let newAdder = fn(x) { fn(y) { x + y } }; let addTwo = newAdder(2); x //identifier not found: x

Complete Example

Builtin

let map = fn(arr, f) {
	let iter = fn(arr, accumulated) {
		if (len(arr) == 0) {
			accumulated
		} else {
			iter(rest(arr), push(accumulated, f(first(arr))));
		}
	};
	iter(arr, []);
};
let a = [1, 2, 3, 4];
let double = fn(x) { x * 2 };
map(a, double);

HashMap

let people = [{"name": "Alice", "age": 24}, {"name": "Anna", "age": 28}];
let getAge = fn(person) { person["name"]; };
return getAge(people[0]) + getAge(people[1]);

Benchmark

$ cargo run --release --bin benchmark -- --vm
$ cargo run --release --bin benchmark -- --eval

TODO

• Impl Compiler
• Impl VM
• Add Pipeline with Stages: fmt, check, clippy, test, build
• Optimize overall performance
• Fix clippy warnings

License

MIT License (LICENSE).