Ross Paterson wrote:
I'd like to suggest (again) treating sequences differently from the rest, and that they should be defined by a class: * the class fits within Haskell 98, because sequences have only one parameter, and it's unconstrained. * polymorphism is likely to be more useful with sequences because of the wide range of implementations suited to different purposes. * polymorphism lets you do general adaptors, like Edison's SizedSeq (adding a size) and RevSeq (presenting a reversed view).
I admit, that supplying further modules for SizedSeq and RevSeq would involve some code duplication. (If several implementations of sequences are used simultaneously qualification is required.) But maybe you could elaborate the advantages of a class that you suggest in more detail. For generic algorithms with sequences, I would suspect smaller classes, e.g. like Monoid, to be more appropriate. Christian P.S. where can I download the actual code of edison? http://www.haskell.org/ghc/docs/edison/