@hackage hpp0.1.0.0

hpp is a Haskell pre-processor that is also a C89/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 simple macro expansion while still allowing multi-line string literals, an invocation might look like,

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 -optP--cpp #-}