Introduction

Rune is a handcrafted, interpreted programming language designed for learning, exploration, and understanding programming language internals.

Rune uses plain-English keywords and a clean, consistent grammar that can be learned in an afternoon. It is a dynamically typed, interpreted language featuring closures, first-class functions (spells), and a small but complete standard library.

spell greet(name) {
    write("Hello, " + name + "!")
}

greet("world")

Core Characteristics

Rune was built from the ground up to showcase the components of a programming language without unnecessary complexity:

• Plain-English Syntax — Read code like a sentence using keywords like set, write, if / otherwise, while, repeat, and count from/to.
• Handcrafted Pipeline — Complete compiler pipeline with a hand-rolled scanner (lexer), recursive-descent parser, Abstract Syntax Tree (AST), and a tree-walk interpreter.
• Environment Scope Chains — Fully implemented closure support using parent-linked scoping environment frames.
• Dynamic Typing — Variables are dynamically typed and can hold number, word, boolean, or empty values.
• Zero Dependencies — Written in pure Python 3.10+ with no external packages required.