On Jan 9, 2007, at 7:52 PM, Marc Weber wrote:
Hello.
Is here the right place to request a list class? eg class List l e where (:) :: e -> l e -> l e head :: ..
Note that this approach isn't quite flexible enough. Your example forces the container type to have kind * -> *, and therefore can't support certain specialized containers like ByteString. There is a class like this in the Edison library (http:// www.eecs.tufts.edu/~rdocki01/edison.html), it is called Seq (Haddocks: http://www.eecs.tufts.edu/~rdocki01/docs/edison/Data- Edison-Seq.html). However, it suffers the same kind flexibility issues as your List class. Other classes in Edison take a MPTC +fundep approach and I'm not sure why Seq doesn't. Can you comment on this, Rob?
This might be used in Data.Set, Data.Map
class StorableAsList l e t where fromList :: l e -> t toList :: t -> l e
This is subsumed by other Edison functionality.
I'd like to help implementing/ writing it.
Do you consider this beeing a useful enhancement?
Oh yes, but let's avoid reinventing the wheel if at all possible. Spencer Janssen