[Haskell-beginners] Parser as an instance of the monad class

[Iustin Pop]

On Tue, Jan 11, 2011 at 11:39:48PM -0800, Paul Higham wrote:
> There are a number of ugly things that you can do at this point that
> are just plain wrong, so I thought that the right thing to do would
> be to get the Parser type to be manifested as an instance of the
> Monad class.  Ok, now what?  Since Parser is only a type synonym it
> cannot be used directly in the following way:
> 
>    instance Monad Parser where
>       return v = . . .
>       p >>= f  = . . .
> 
> but since Parser is not an algebraic type as it is defined that
> won't work either.  So how do you do it?  help .

Have you looked at the book's website? He provides the entire
Parsing.lhs library, and you can see there an example of how to do it.

regards,
iustin