On Mon, 2009-04-20 at 18:26 -0500, Ian Duncan wrote:
No instance for (Stream s m Char) arising from a use of `spaces' at tree.hs:18:32-37 Possible fix: add an instance declaration for (Stream s m Char) In the first argument of `between', namely `spaces' In the second argument of `(<$>)', namely `(between spaces (char ':') (many1 alphaNum))' In the expression: Label <$> (between spaces (char ':') (many1 alphaNum))
When I test this function in ghci, I have no problems, yet whenever I try to open it in a file it fails. What am I doing wrong?
Looks like you're getting bitten by the monomorphism restriction. {-# LANGUAGE NoMonomorphismRestriction #-} at the top of the source file to make it go away. The MR is a real usability problem for Parsec 3, sadly :-( You may find it easier to work with the latest version of Parsec 2, which is still the recommended version for most purposes. -- Philippa Cowderoy <flippa@flippac.org>