[Haskell-cafe] Polymorphic algebraic type constructors
MR K P SCHUPKE
k.schupke at imperial.ac.uk
Wed Jun 23 07:40:08 EDT 2004
What you are suggesting - whilst it seems reasonable requires
a fundamental change to the type system. At the moment []
signifies an empty list of type 'a' ... what you are suggesting
requires [] to have a different type from [a]... This means
a simple case statement :
case a of
(a:as) ->
[] ->
would now not type because everything on the LHS of the cases must
be the same type.
Infact I don't see how it could be any other way... 'a' has a type
call it [a]... how could [] be any other type?
Keean.
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