Language.Haskell.Parser and layout rules

17 Feb 2005

      The function Language.Haskell.Parser.parseModule behaves somehow strange and
disagrees with ghc-6.* about the set of accepted inputs. An example:

-- file T1.hs:
main = do args <- getArgs
	  if null args then return [] else do
	  ps <- mapM process args
          mapM print ps
-- file T2.h2
main = do args <- getArgs
	  if null args then return [] else do
	  ps <- mapM process args
           mapM print ps

Note the difference is an additional whitespace in T2.

I think both codes are perfectly valid, but parseModule fails on T1. Is anyone
able to explain why?

Thanks, Mirko Rahn

---- 

mirak@loop:~> ghci
   ___         ___ _
  / _ \ /\  /\/ __(_)
 / /_\// /_/ / /  | |      GHC Interactive, version 6.4.20050211, for Haskell
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