Loom

Loom is a functional language that compiles to Rust. It features:

• Module system with provides / requires interfaces for dependency injection
• Product types (type Point = x: Float, y: Float end)
• Sum types (enum Color = | Red | Green | Blue end)
• Refined types (type Email = String where valid_email)
• Effect tracking (fn fetch :: Int -> Effect<[IO], User>)
• Design-by-contract (require: / ensure: clauses → debug_assert!)
• Pipe operator (a |> f |> g)

Install

cargo build --release
# binary at target/release/loom

Usage

loom compile src/pricing.loom              # writes src/pricing.rs
loom compile src/pricing.loom -o out.rs   # custom output path
loom compile src/pricing.loom --check-only # type/effect check only

Phase 1 status

Feature	Status
Lexer (logos)	✅
Recursive-descent parser	✅
Type checker (symbol resolution)	✅
Effect checker (transitive effects)	✅
Rust code emitter	✅
CLI (loom compile)	✅
Full expression parser	✅
Corpus examples	✅

Phase 2 will add: type inference, full pattern exhaustiveness checking, WASM back-end, and language server support.