Andrew Coppin schrieb:
Haskell has ADTs. Most of the time, these work great. As I've written in
several other places (but possibly not here), OO languages tend to
factor the problem the other way. That is, if I want a binary tree, an
OO language makes me split the type and all of its
The other day I saw the green field Haskell discussion on Reddit. Of
course, I could give you a very long list (ha!) of things that I would
change about Haskell. (This would probably begin with expunging
Monad.fail with extreme prejudice...) But there's one particular feature
which is
You want polymorphic variants. Check out O'Caml, or MLPolyR.
Subtyping is not very compatible with first-class functions. If you have
subtype-bounded polymorphism
(forall A a subtype of T, ...), and your subtype relation says A - B is a
subtype of C -D whenever
A is a supertype of C and B is a
your subtype relation says A - B is a subtype of C -D whenever
A is a supertype of C and B is a subtype of D, then checking subtyping is
undecidable.
In fashion terms: operator (-) is contravariant in its first argument and
covariant in its second.
;)
2011/3/16 Brandon Moore
