[Haskell-cafe] Either Monad and Laziness

[Malcolm Wallace]

On 12 Sep 2012, at 16:04, Eric Velten de Melo wrote:

>>>> The behaviour I want to achieve is like this: I want the program when
>>>> compiled to read from a file, parsing the PGM and at the same time
>>>> apply transformations to the entries as they are read and write them
>>>> back to another PGM file.
>>> 
>>> Such problems are the main motivation for iteratees, conduits, pipes,
>>> etc. Every such library contains procedures for doing exactly what you
>>> want.
>>> 
> 
> It would be really awesome, though, if it were possible to use a
> parser written in Parsec with this, in the spirit of avoiding code
> rewriting and enhancing expressivity and abstraction.

The polyparse library on Hackage is another parser combinator framework that allows lazy incremental parsing.
http://hackage.haskell.org/package/polyparse

A PDF paper/tutorial is here:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.118.1754&rep=rep1&type=pdf

Regards,
    Malcolm