Preprocessors (was: state of the cabal (preprocessors))

I've recently run into a problem using the preprocessor (ghc -cpp). It seems it barfs on 's (apostrophe). Annoying, since naming variables something-prime is a fairly common idiom. Is this something that has a workaround, or could be fixed? (The specific problem is redefining 'head' in a macro and using it like: let w' = head ... -- breaks One workaround is to write it as: let w' = head ... -- works ) -kzm -- If I haven't seen further, it is by standing in the footprints of giants