Question about use of | in a class declaration

Jerzy Karczmarczuk
Wed, 21 Aug 2002 17:13:53 +0200

Hal Daume III wrote:
> This is a functional dependency.  You can probably find informationin the
> GHC docs.  It's a way of telling the compiler how to derive type
> information on multiparameter classes.

Oh, can you?

Here what the User's Guide says:

> Functional dependencies are implemented as described by Mark Jones in 
> "Type Classes with Functional Dependencies", Mark P. Jones, In Proceedings 
> of the 9th European Symposium on Programming, ESOP 2000, Berlin, Germany, 
> March 2000, Springer-Verlag LNCS 1782.
> There should be more documentation, but there isn't (yet). Yell if you need it.

Folks, let's yell together!
This is a nice feature. It SHOULD be better known.
If Simon's team has no time to write it, perhaps it would be nice to put
the reference to Mark's paper on line?

Jerzy Karczmarczuk
Caen, France