[Haskell-cafe] Monadic parser vs. combinator parser

[Ertugrul Söylemez]

Jan Stolarek <jan.stolarek at p.lodz.pl> wrote:

> Thanks for replies guys. I indeed didn't notice that there are monads
> and applicatives used in this parser. My thought that monadic parsers
> are more verbose came from Hutton's paper where the code is definitely
> less readable than in example I provided.
>
> There is one more thing that bothers me. It is easy to write a parser
> that returns Nothing when parsing fails. But I can't figure out a way
> to add meaningful error messages so that the user knows where did the
> parsing fail. I experimented with using Either so that I can use Left
> to pass error messages but this turned out to be inflexible and
> clutered the code. I will be greatful for any ideas.

Remember that 'Either e' is also a monad. =)


Greets,
Ertugrul

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