2010/10/31 Nils Schweinsberg <m...@n-sch.de>: > Hi! > > I'm having a really hard time to write a correct parser for a small language > I've developed. I have been trying to write a parser using parsec, but > always get a lot of error messages like "unexpected "\n", expected ..., > new-line or..." when trying to run the parser. > [snip]
Hi, I can't really tell from your description, but maybe this is because of the way Parsec works when it deals with alternatives. When you combine several parsers with e.g. '<|>' or 'choice', an alternative that can consume some input but fails will make the whole combined parser fail too. So you have to either factorize you parsers or use the 'try'. See the documentation for 'try' at http://hackage.haskell.org/packages/archive/parsec/3.1.0/doc/html/Text-Parsec-Prim.html . HTH, Thu _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
