Hi Mark, On Sun, Nov 03, 2013 at 03:01:32PM -0800, Mark Lentczner wrote:
This does not appear to be the case, at least any more. The way GHC invokes gcc for c pre-processing only removes /*…*/ style comments, not the later // style:
Yes, I can reproduce your behaviour on my system and ghc seems to call cpp with some options, because the default behaviour removes C++ style comments: dan@machine ~> cat cpp.test /* comment */ code // comment dan@machine ~> cpp cpp.test # 1 "cpp.test" # 1 "<command-line>" # 1 "cpp.test" code I can't recall it exactly, if I had the C++ comment issue only with cpphs, because cpp had problems with some Haskell code, or if I also had the issue with cpp itself. I just tried cpphs and its default behaviour removes the C++ style comments: dan@machine ~> cat test.hs (//) :: Double -> Double -> Double a // b = a / b / b main = print $ 1 // 2 dan@machine ~> ghci Prelude> :set -cpp -pgmPcpphs -optP--cpp Prelude> :l test [1 of 1] Compiling Main ( test.hs, interpreted ) test.hs:2:1: parse error (possibly incorrect indentation or mismatched brackets) Failed, modules loaded: none. That's a bit unfortunate, that the default behaviour of ghc using cpp and cpphs differs. Greetings, Daniel