Proposal: Data.Stream

Stefan Holdermans stefan at
Thu Jul 12 09:41:07 EDT 2007


> I have to admit that I don't really understand the distinction  
> between Haskell's lists and colists (or, in general, datatypes in  
> Haskell and codatatypes). To me, lists are inductive and colists  
> are coinductive, i.e., the former are the least and the latter the  
> greatest fixed point of the underlying functor. Thus, Haskell's  
> list datatype actually models colists (and algebraic datatypes in  
> Haskell are coinductive by default). This thread seems to  
> implicitly assume a different interpretation of the prefix "co" but  
> I don't really understand what this interpretation is.

In Haskell, coinductive types and inductive types coincide. So,  
Haskell's [] models both lists and colists.



More information about the Libraries mailing list