Ormolu
A formatter for Haskell source code
Ormolu is a formatter for Haskell source code. Using GHC's own parser to avoid parsing problems caused by haskell-src-exts. Let some whitespace be programmable. The layout of the input influences the layout choices in the output. This means that the choices between single-line/multi-line layouts in certain situations are made by the user, not by an algorithm.