As per the docstring:
class HaskellLexer(RegexLexer): """ A Haskell lexer based on the lexemes defined in the Haskell 98 Report.
I suggest either updating the lexer, extending it, or creating a new one for the 2010 report.
I'd like to work on it as I'm pretty good with regular expressions, Python, and I'm learning Haskell. But perhaps there's a good reason for me not to that I'm not aware of.
(I would assign to myself but the UI won't let me.) Thanks.