Language Reference

This is the complete reference for the mimas language, version 0.1.0. It describes the syntax and semantics of the language itself — the parts you write in a .mim file. Extending mimas from Rust is covered separately in Extension with Rust.

mimas is a statically typed, embeddable scripting language for Rust. It borrows much of Rust’s syntax and ergonomics and reshapes the rest to deliver what a scripting layer is good for: fast iteration, quick compile times, and runtime flexibility.

enum Shape {
    Circle(float),
    Rect(float, float),
}

fn area(s: Shape) -> float {
    match s {
        Shape::Circle(r) => 3.14159 * r * r,
        Shape::Rect(w, h) => w * h,
    }
}

let shapes = [Shape::Circle(2.0), Shape::Rect(3.0, 4.0)];
let total = for s in shapes collect area(s);
print(f"areas: {total}"); // areas: [12.56636, 12]

How to read this reference

Each page introduces one concept with short, runnable examples. Every snippet here is real mimas; you can drop one into a file and run it:

mimas example.mim

A few conventions used throughout:

• We annotate types liberally (let a: int = 0) to make each example’s behavior explicit. In practice mimas infers most of them — you only need annotations on function signatures and type declarations. See Variables.
• A // -> comment shows what an expression evaluates to or what print outputs.
• A // compile error: … comment marks code that is intentionally rejected, with the reason the compiler gives.