Fourmolu vs stylish-haskell
Fourmolu
fourmolu.github.iostylish-haskell
github.comSide by side
| Figure | Fourmolu | stylish-haskell |
|---|---|---|
| Price from | Free | — |
| Free plan | Yes | — |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | — |
| Windows | Yes | Yes |
| Linux | Yes | Yes |
| Plans published | 1 | 0 |
| Spec score · Code Formatting Tools | 8.3 (#4) | 6.8 (#30) |
| Configuration | Settings can be provided in a fourmolu.yaml file or as command-line options. | Formatting is customizable through YAML configuration files, with settings available at directory, project, user, or default level. |
| Installation | The project documents installation through GHCup, Cabal, Stack, and dotslash. | The README documents installation with Stack or Cabal and package-manager installation for Debian, Ubuntu, and Arch Linux. |
| Purpose | Fourmolu formats Haskell source code and is a configurable fork of Ormolu. | stylish-haskell is a Haskell code prettifier designed to help with formatting tasks such as cleaning up import statements. |
Plans
In their own words
Fourmolu
Fourmolu is a configurable formatter for Haskell source code and a fork of Ormolu. It uses GHC’s parser and aims to keep diffs small, produce idempotent output, and handle large projects. Set formatting options in `fourmolu.yaml` or pass them on the command line. Controls include indentation, line length, import grouping, record layout, Haddock comments, Unicode output, and operator fixities. Fourmolu can find the relevant Cabal file to read default extensions and dependencies that help determine fixities. Magic comments can disable formatting for selected code, and command-line options can target a line region. There is an interactive browser demo with configurable formatting and program options. Installation instructions cover GHCup, Cabal, Stack, and dotslash; editor integration is documented through Haskell Language Server. The project recommends a GitHub Action to keep projects formatted. Its listed current release is v0.21.0.0. CPP handling is experimental and limited to simple cases where conditionals surround top-level declarations. Output always uses LF line endings, which can cause check mode to fail on CRLF files.
stylish-haskell
stylish-haskell has no write-up on Specifiction yet; its figures are above.