[Haskell-cafe] seq (was: Article review: Category Theory)
lennart at augustsson.net
Fri Jan 19 22:47:42 EST 2007
This solution was used in the first place. But then some people were
to actually use the Eval (as Seq was called) class, so they wanted
a polymorphic seq. And so we're in this mess. And it is a mess,
e.g., the foldr/build transformation ghc uses to fuse list processing
isn't really valid when you have seq.
On Jan 19, 2007, at 18:09 , Brian Hulley wrote:
> Neil Mitchell wrote:
>> Hi Brian,
>>> Is there any solution that would allow excess laziness to be removed
>>> from a Haskell program such that Hask would be a category?
>> class Seq a where
>> seq :: a -> b -> b
>> Then you have a different seq based on the types, and it doesn't go
>> wrong. You would probably want deriving Seq support.
> This seems an amazingly neat solution to a really terrible problem,
> 1) Does anyone know why this was not used in the first place?
> 2) Would it be good to use this in future versions of Haskell?
> 3) Is there any practical program which requires the current seq
> that could not be rewritten to use the typeclass seq?
> Thanks, Brian.
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
More information about the Haskell-Cafe