ghc-exactprint

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 SrcSpan

• 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 text.

• 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