10 May
2005
10 May
'05
10:16 a.m.
Ashley Yakeley wrote:
In article <r02010400-1040-A0BE089CBF6111D99910000393758032@[10.0.1.2]>, David Menendez <zednenem@psualum.com> wrote:
data Vec 0 a = Nil data Vec s v a = Cons a (v a)
Some aliases for convenience:
type Vec 1 = Vec s Vec 0 type Vec 2 = Vec s Vec 1 type Vec 3 = Vec s Vec 2 type Vec 4 = Vec s Vec 3
I don't understand this at all, and neither does GHC.
You seem to have lost the underscores :-) It can be written without underscores as: data Vec0 a = Nil data VecS v a = Cons a (v a) type Vec1 = VecS Vec0 type Vec2 = VecS Vec1 All the best, Daan Leijen Btw. David: nice example of useful GADT use!