[Haskell-cafe] Re: Parsec is being weird at me
andrewcoppin at btinternet.com
Sat Aug 25 16:04:55 EDT 2007
Stefan O'Rear wrote:
> On Sat, Aug 25, 2007 at 08:18:29PM +0100, Andrew Coppin wrote:
>> But hang on a minute...
>> "many" parses 0 or more occurrances of an item.
>> "sepBy" parses 0 or more occurrances of an item, seperated by another item.
>> "endBy" parses 0 or more occurrances of an item, terminated by another
>> "sepEndBy" parses 0 or more occurrances of an item, seperated *and*
>> terminated by another item.
>> ...except that "endBy" doesn't seem to be working right. :-S
> There is one other little bit of documented behavior. Parsec's normal
> combinators only parse LL(1) grammars. Consult any work on formal
> languages for the exact meaning and all the consequences, however for
> this example it serves to note that after seeing abc, the single
> character of lookahead '#' is not sufficient to determine the correct
Heh. Starting to wish I had a significantly higher IQ...
I thought the whole *purpose* of the endBy combinator was to keep
applying one parser until the other one succeeds?
In the example I posted, the two parsers are quite trivial. But in the
real problem I actually want to solve, they are very non-trivial...
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