Package Info


ExactPrint for GHC


Using the API Annotations available from GHC 7.10.2, this library provides a means to round trip any code that can be compiled by GHC, currently excluding lhs files.

It does this with a phased approach

  • Delta - converts GHC API Annotations into relative offsets, indexed by


  • Transform - functions to facilitate changes to the AST, adjusting the

annotations generated in the Delta phase to suit the changes.

  • Print - converts an AST and its annotations to properly formatted source


  • Pretty - adds annotations to an AST (fragment) so that the output can be

parsed back to the same AST.

Note: requires GHC 7.10.2 or later.

License: BSD-3-Clause



Package Version Update ID Released Package Hub Version Platforms Subpackages info GA Release 2018-08-01 15
  • AArch64
  • ghc-ghc-exactprint
  • ghc-ghc-exactprint-devel info GA Release 2018-07-31 15
  • ppc64le
  • ghc-ghc-exactprint
  • ghc-ghc-exactprint-devel info GA Release 2018-07-30 15
  • x86-64
  • ghc-ghc-exactprint
  • ghc-ghc-exactprint-devel