Re: [Haskell-cafe] Musings on type systems

Ketil Malde wrote:

data Sum a b = A a | B b -- values = values in a + values in b data Prod a b = P a b -- values = values in a * values in b

I guess this makes [X] an exponential type, although I don't remember seeing that term :-)

I would expect the "exponential type" to be (a -> b):

type Exp b a = a -> b -- values = values in b ^ values in a

Tillmann