ghc-hpp
A Haskell pre-processor
hpp is a Haskell pre-processor that is also a C90-compatible pre-processor (with the addition of a --cpp flag). It is packaged as both a library and an executable. To use as a Haskell preprocessor for resolving #ifdef conditionals and macro hpp -DDEBUG Foo.hs To use as a C preprocessor, an invocation might look like, hpp -DDEBUG --cpp foo.c To have GHC use hpp as the C pre-processor, add this line to the top of a Haskell source file that makes use of the CPP LANGUAGE pragma, {-# OPTIONS_GHC -cpp -pgmPhpp #-} Or add this line to your .cabal file: ghc-options: -pgmPhpp Note that you will need to ensure that the hpp executable is available in your build environment (e.g. you can add hpp as a build-depends in your .cabal file).
BSD-3-Clause