Abstract Collections vs. FunDeps

Dylan Thurston dpt at lotus.bostoncoop.net
Fri Apr 2 11:25:34 EST 2004


On Fri, Apr 02, 2004 at 11:21:05AM +0200, Robert Will wrote:
> On Fri, 26 Mar 2004, Dylan Thurston wrote:
> > Also, they're vitally necessary for certain algorithms and for speed
> > (since not all ways of making containers can contain all items).
> 
> If you mean restricting some Containers to certain element types (Patricia
> trees and so on), this is perfectly possible without FunDeps.  ...

I did mean that, and thanks for explaining how I was being silly!

I am now more convinced than before that the 'Eq' and 'Ord'
constraints on your classes don't belong; if I want to implement the
ridiculously slow list-based implementation of Sets currently in the
Prelude, which only needs equality and nothing else, why can't I?

Peace,
	Dylan
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