Hi Peter,
Sorry for the previous, incomplete reply.
Eudora thinks that Ctrl-E should mean: Send immediatEly instead of
End-of-line...
>class ResourcePool p where
> newp :: p -> e -> p -- adds new element e to the resource pool p
If you want to add the element of type e to the pool, the type of
the pool should incorporate this type. Therefore, it should be
"p e" for example.
newp :: poolOf elem -> elem -> poolOf elem
>As one instance of this class, I want a resource pool where the type "e"
>becomes a pair consisting of an Id and a value (x), as follows:
>
>data Pool id x = EmptyPool | NewPool id x
I do not completely understand what you want to make.
I would expect something like:
data Pool elem = EmptyPool | NewPool elem (Pool elem)
and then:
instance ResourcePool Pool where
newp p elem = NewPool elem p
>On the subject of multi-parameter classes, the hugs system does not
>seem to permit them. Is the story different on GHC?
Hugs 1.3c does, but I don't know whether you need them
for your problem. Anyway, it can be downloaded at:
http://www.cs.nott.ac.uk/~mpj/hugs13/
Bye,
Arjan
