[Haskell-cafe] extension to filter with external program (was: Current status of Mavericks CPP)

hi, i may certainly be missing something, as i only used cpp in haskell for conditional compilation. having said that: i'd like to have (instead of LANGUAGE CPP) the following extension. LANGUAGE FilterWithExternalProgram my_cpp that would make it possible to use a cpp implementation implemented separately from ghc and would leave it to the ecosystem to implement best practices (i.e. a haskell implementation of cpp or the proposed declarative extension). i _guess_ that should also make it easier to use compile-to-haskell programs like she. maybe a hypothetical template haskell alternative might also work with it. regards, tobias florek