[Haskell-cafe] Merging classes

[pat browne]

Hi,
Following on from my earlier *Merging modules* email, where I tried to
simulate ontology merging with Haskell modules;

http://article.gmane.org/gmane.comp.lang.haskell.cafe/64943

I *think* that the type of merging that I am attempting is difficult
with modules so I gave classes a try. I did not get very far (see
below). Perhaps I need a combination of type classes and modules.
In fairness this is more of a specification task than a programming task
and perhaps I am barking up the wrong tree.
Any help appreciated.

Regards,
Pat



==============================================
attempting an ontology merge with type classes
For specification of requirement see
http://article.gmane.org/gmane.comp.lang.haskell.cafe/64943
==============================================
-- Data types for COMMON
data  Woman = WomanC
data Person  = PersonC

-- Additional data type for ONTOLOGY1
data Bank = BankC

-- Additional data type for ONTOLOGY2
-- but how do I let type Bank have the same name in both classes and
-- still be distinct (homonyms) in the merged class
--   data Bank = BankC

class  COMMON a b where
class  (COMMON a b) => ONTOLOGY1 a b where
class  (COMMON a b) => ONTOLOGY2 a b where
class  (ONTOLOGY1 a b, ONTOLOGY2 a b) => MERGEDONTOLOGY a b where

-- not really sure how to proceed from here
instance COMMON Woman Person where