Luma

A small, statically-typed programming language with clear syntax and kind error messages.

void main() {
    print("Hello, Luma!");
}

Note: This is the reference implementation (a0.1) — a Rust-based interpreter. A rewrite in Luma itself is planned for a0.2. This repo will be archived once the rewrite is complete.

---

Why Luma?

Luma was built by someone who struggles to write code independently due to disabilities affecting reading, mathematics, focus, and cognitive load. Working with AI tools made building a language possible — but it also made clear how important predictable, explicit design is.

Luma is for anyone who finds programming languages overwhelming. It won't surprise you. It won't judge you. It'll tell you exactly what went wrong and how to fix it.

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Getting Started

Install

Clone and build with Cargo:

git clone https://github.com/dylanisaiahp/luma
cd luma
cargo build --release
cp target/release/luma ~/.local/bin/luma

Usage

luma new myproject        # Create a new project
luma new --file mymod     # Create a single .lm file with module declaration
luma run                  # Run from luma.toml entry point
luma run main.lm          # Run a specific file
luma check main.lm        # Check for errors without running
luma run --time           # Show execution time
luma run --debug all      # Debug output

Project Structure

myproject/
├── source/
│   └── main.lm
├── luma.toml
└── README.md

[project]
name = "myproject"
version = "0.1.0"
description = ""
entry = "source/main.lm"

---

Examples

Hello World

void main() {
    print("Hello, Luma!");
}

Functions

int add(int x, int y) {
    return x + y;
}

void main() {
    print(add(3, 4));   # 7
}

Control Flow

void main() {
    for i in range(1, 6) {
        if i % 2 == 0 {
            print("&{i} is even");
        }
    }
}

Error Handling

worry(int) safe_divide(int a, int b) {
    if b == 0 {
        raise "cannot divide by zero";
    }
    return a / b;
}

void main() {
    int result = safe_divide(10, 0) else err {
        print(err);
        return;
    };
    print(result);
}

Structs

struct Point {
    int x;
    int y;

    int sum() {
        return x + y;
    }
}

void main() {
    Point p = Point(x: 3, y: 7);
    print(p.x);       # 3
    print(p.sum());   # 10
}

Multi-file Projects

Every importable file must declare its module name at the top:

# source/greet.lm
module greet;

string greet(string name) {
    return "Hello, &{name}!";
}

# source/main.lm
use greet;

void main() {
    print(greet("Luma"));
}

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Error Messages

Luma tries to tell you exactly what went wrong and how to fix it:

[E010] Error: Type mismatch: expected int, got string
   ╭─[ main.lm:3:15 ]
   │
 3 │     int x = "hello";
   │             ───────
   │                ╰── Make sure the value type matches the variable declaration.
───╯

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Roadmap

See ROADMAP.md for what's done and what's coming.

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Contributing

See CONTRIBUTING.md.

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License

MIT — see LICENSE.