[Haskell-beginners] Re: Applicative Parsec

Matthias Guedemann wrote:

Hi Brent,

thanks for the illustrative example.

...

For example, consider parsing a file which contains a positive integer, followed by that many letters. For example,

3xyz 12abcdefghijkl

are two instances of this format. In order to parse this, a monadic interface is required, since the result of parsing the number must be used to decide how many things to parse after that.

I see, but as long as I want to parse context free grammars, it is sufficient?

Yep. The monadic version can handle context-sensitive grammars. Incidentally, this is why the Utrecht parsing libraries ( uu-parsinglib ) only offers an applicative interface. Regards, apfelmus -- http://apfelmus.nfshost.com