[Haskell-cafe] Re: Parsec lookahead and <|>
Martijn van Steenbergen
martijn at van.steenbergen.nl
Fri Aug 21 08:40:25 EDT 2009
Thanks for your replies.
Job Vranish wrote:
> Martijn, how did you encounter this problem?
My list of input symbols contains some extra information and I was using
lookahead to query for that information before doing the actual parsing.
I was using it in various places, including a list of choices separated
by <|>. I was assuming it wouldn't affect the choice but it turned out
that Parsec was always going for the first one because I used a
lookahead (see la) that always succeeds.
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