On Mon, Sep 6, 2010 at 11:55 PM, Maciej Piechotka
Reference is class which generalizes references and monads they exists in. It means that IORef, STRef and others can be accessed by common interface.
Currently it is of form:
class Reference r m where
1. There was a proposal to rename the class to MonadRef or MonadReference. IMHO it would imply m -> r functional dependency and therefore disallow the instances for both MVar IO and IORef IO
2. Should the functional dependencies or type famillies be introduced? Personally I don't think so as I would like to allow all of the following:
- IORef IO - MVar IO - IORef (ContT IO) - MVar (ContT IO)
Any feedback mostly welcome.
Regards PS. Darcs repository will be available soon
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I've played with a somewhat similar idea: darcs get http://code.haskell.org/~basvandijk/code/only-read-or-write-vars API Docs + Hyperlinked source: http://code.haskell.org/~basvandijk/code/only-read-or-write-vars/doc/html/on... This is not released (yet) because I'm unsure about the design. Especially, I'm unsure whether parameterizing Readable with α is a good idea: class Readable v m α | v → m where read ∷ v → m α and whether parameterizing Writable with α and β is a good idea: class Writable v α m β | v → m where write ∷ v → α → m β They do allow some Regards, Bas