Hi, probably the best way is to write a parser using ReadP/ReadPrec and then instance Read SomeType where readPrec = yourParser If you wish, I could send you a few examples (not very interesting, but they might help getting you going). Cheers, Daniel Am Samstag, 28. Oktober 2006 23:49 schrieb Tiago Veloso:

Hi,

I am trying to find out how to work with the Read Class for a school project, i need to declare instances of Read for a few data types.

My problem is that i do not know how to do it, i mean i do not know how to build a Read instance, i do know about it for the Show Class.

Can some one help?

Thanks

Tiago Veloso

Tiago Veloso wrote:

I am trying to find out how to work with the Read Class for a school project, i need to declare instances of Read for a few data types.

My problem is that i do not know how to do it, i mean i do not know how to build a Read instance, i do know about it for the Show Class.

if you run ghc with -ddump-deriv, you will see the instances that get generated when you use "derive". Cheers, Misha