Antoine Latter wrote:
Sure! Using type-families:
class Container c where
type Elem c
insert :: Elem c -> c -> c
instance Container [a] where
type Elem [a] = a
insert = (:)
instance Container ByteString where
type Elem ByteString = Word8
insert = BS.cons
instance Ord a => Container (Set a) where
type Elem (Set a) = a
insert = Set.insert
That's more or less how I was hoping it works. (Was unsure of the actual
syntax, and the documentation is rather terse.)
So there's a class called Container that has a _type_ that is
_associated_ with it, representing the type of the elements? And you can
set that type to be either a type variable or an explicit type?
Now the hard part is coming up with a proper API and class hierarchy.
So... exactly like in every OOP language in existence then? ;-)
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