tweag/ormolu

Health v2 · maintenance only

Flags: no_license

Adoption not part of the score

1072 stars · 89 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

Ormolu is a formatter for Haskell source code that uses GHC's own parser and enforces a single, unconfigurable formatting style with minimal diffs and idempotent output. It ships as a CLI tool, a library, and a browser-based playground (Ormolu Live) compiled to WASM.

Use cases

• format haskell source code
• enforce consistent haskell code style across a project
• check haskell formatting in CI
• format haskell code in the browser
• integrate haskell formatting into an editor
• reformat haskell code with minimal diffs

When to choose

• you want one canonical Haskell style with no configuration debates
• you need a formatter that handles modern GHC language extensions reliably
• you want idempotent formatting suitable for large codebases and CI checks

When to avoid

• you need configurable formatting options or multiple style presets
• you want a formatter for languages other than Haskell
• you prefer a style that preserves your existing whitespace choices entirely

Facets

cli-tool · maturity active

formatter cli parser developer-tools programming-languages windows cli wasm haskell code-style idempotent-formatting ghc-parser command-line linux macos

Member repositories

For agents

markdown · JSON · MCP: product_card(name="tweag/ormolu")