🌙 Luno Programming Language

Luno is a general-purpose, interpreted scripting language inspired by Python. It features clean, indentation-based syntax with first-class functions, classes with inheritance, string interpolation, and pattern matching.

🚀 Features

• Clean syntax — Indentation-based blocks, no semicolons, no braces
• First-class functions — Closures, lambdas (lam x => x * 2), default args
• Classes & inheritance — class Dog(Animal): with self-based methods
• String interpolation — `Hello, ${name}!` with backtick strings
• Pattern matching — match/case expressions
• Error handling — try/catch/finally with custom error types
• Immutability — let for mutable, const for immutable bindings
• Built-in functions — print, input, len, range, type, and more
• Interactive REPL — Explore Luno interactively with luno repl

📥 Installation

git clone https://github.com/IMDevFlare/luno
cd luno
cargo build --release

The binary will be at ./target/release/luno.

🛠 Usage

Run a file

# Using the run subcommand
cargo run -- run examples/hello.luno

# Or directly
cargo run -- examples/hello.luno

# With the built binary
./target/release/luno run examples/hello.luno

Supported file extensions: .luno, .ln

Start the REPL

cargo run -- repl
# or just
cargo run

🌙 Luno v0.1.0 — Interactive REPL
Type 'exit' or Ctrl+C to quit.

luno> print("Hello from Luno!")
Hello from Luno!
luno> let x = 42
luno> print(x * 2)
84

📜 Example

let name = "world"
print(`Hello, ${name}!`)

fn factorial(n: int) -> int:
    if n <= 1:
        return 1
    return n * factorial(n - 1)

print(factorial(10))

class Animal:
    fn init(self, name: str):
        self.name = name
    fn speak(self):
        print(`${self.name} makes a sound.`)

class Dog(Animal):
    fn speak(self):
        print(`${self.name} barks!`)

let d = Dog("Rex")
d.speak()

Output:

Hello, world!
3628800
Rex barks!

📂 Project Structure

luno/
├── Cargo.toml           # Rust project manifest
├── src/
│   ├── main.rs          # CLI entry point (run / repl)
│   ├── lexer.rs         # Tokenizer with indentation tracking
│   ├── parser.rs        # Recursive-descent parser → AST
│   ├── interpreter.rs   # Tree-walking evaluator
│   └── repl.rs          # Interactive REPL loop
├── examples/
│   └── hello.luno       # Example program
├── GRAMMAR.md           # Complete language grammar reference
├── CHANGELOG.md         # Version history
└── TODO.md              # Roadmap and planned features