Your class looks like Unfoldable from
Data.Collectionshttp://hackage.haskell.org/package/collections-api-1.0.0.0/docs/Data-Collect....
foo is insert and bar is empty. The other three methods can be defined in
terms of insert and empty.
On 21 April 2014 07:09, Bardur Arantsson
Hi all,
I was wondering if anyone out there knows if this type class has a name?
class Foo a e where foo :: e -> a -> a bar :: a
(I also have a fundep a -> e, but that's not essential.)
Essentially the usage is:
You have a sequence of "events" e_i and a starting value "bar" and can use the "foo" function to apply all events to that starting value
foo e_n $ foo e_{n-1} $ ... $ foo e_0 $ bar
and thus get the final value of the a induced by the events e_i.
(I've included the "bar" starting value in the type class, but I suppose it could be supplied by a Default instance.)
Regards,
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe