Ruchy - Self-Hosting Programming Language

Ruchy is a self-hosting programming language with comprehensive tooling and quality engineering practices based on Toyota Way principles.

Quick Start

# Install from crates.io
cargo install ruchy

# Run a one-liner
ruchy -e "println('Hello, World!')"

# Start the REPL
ruchy repl

# Run a script
ruchy run script.ruchy

# Check syntax
ruchy check script.ruchy

# Format code
ruchy fmt script.ruchy

# Lint code
ruchy lint script.ruchy

Current Status - v1.88.0 (September 2025)

🎯 Book Compatibility: 95.6%

• 219 of 229 examples passing
• 100% test coverage
• 94.0/100 TDG quality score (A grade)
• Path to 100%: Only 2 critical bugs remaining

🚀 Recent Achievements

• Main function auto-execution implemented
• Format string processing fixed ({:.2} now works)
• Comprehensive error handling (try-catch-finally, throw, panic!)
• Pattern matching with destructuring (arrays, tuples, objects)
• PMAT v2.68.0+ quality enforcement integrated

📊 Quality Metrics

• Code Quality: 94.0/100 TDG score across 361 files
• Test Coverage: 49.90% overall, 81.2% transpiler
• Zero Technical Debt: No TODO/FIXME/HACK comments
• Pre-commit Gates: Automated quality enforcement

Key Features

Self-Hosting Capability

• Bootstrap compiler written in Ruchy
• Transpiles to Rust for compilation
• Type inference with Algorithm W
• Complete language features for compiler development

Language Features

• Pipeline Operator: data |> transform |> filter
• Pattern Matching: With guards: x if x > 0 => "positive"
• Lambda Syntax: Both |x| x + 1 and x => x + 1
• Module System: use, mod, and :: path resolution
• Error Handling: Result/Option types with ? operator
• Collections: HashMap, HashSet with standard methods
• String/Array Methods: Comprehensive built-in methods

CLI Commands

REPL Features

• Tab completion with context awareness
• Syntax highlighting
• Persistent history across sessions
• Multiline editing
• Magic commands (:help, :load, :save)
• Resource limits (memory, timeout, stack depth)

Example Code

// Function definition
fun parse_expr(tokens: Vec<Token>) -> Result<Expr, ParseError> {
    match tokens.first() {
        Some(Token::Number(n)) => Ok(Expr::Literal(*n)),
        Some(Token::Ident(name)) => Ok(Expr::Variable(name.clone())),
        _ => Err(ParseError::UnexpectedToken)
    }
}

// Pipeline operator
[1, 2, 3, 4, 5]
  |> map(|x| x * 2)
  |> filter(|x| x > 5)
  |> sum()

// Pattern matching with guards
match user_input {
    n if n > 0 => "positive",
    0 => "zero",
    1..=10 => "small range",
    _ => "other"
}

// Collections
let mut map = HashMap()
map.insert("key", "value")
map.get("key").unwrap()

Quality Engineering

Code Quality Standards

• Complexity Limits: Functions must have cyclomatic complexity ≤10
• Zero SATD Policy: No TODO/FIXME/HACK comments allowed
• Lint Compliance: All clippy warnings treated as errors
• Pre-commit Hooks: Automated quality gates prevent regressions

Testing

• Unit tests for core functionality
• Integration tests for CLI commands
• Property-based testing for mathematical invariants
• Fuzz testing for edge case discovery

Quality Gate Script

# Run quality checks
./scripts/quality-gate.sh src

# Checks performed:
# - Function complexity ≤10
# - No technical debt comments
# - All tests passing

Development

# Clone repository
git clone https://github.com/paiml/ruchy.git
cd ruchy

# Build
cargo build --release

# Run tests
cargo test

# Check quality
./scripts/quality-gate.sh src

# Install locally
cargo install --path .

Documentation

• Language Specification
• Development Roadmap
• Change Log
• Contributing Guidelines

Related Projects

• ruchy-book - Language documentation and examples
• rosetta-ruchy - Algorithm implementations
• ruchyruchy - Test suite

License

MIT OR Apache-2.0