22 Dec
2020
22 Dec
'20
12:59 p.m.
Il 22 dicembre 2020 alle 11:48 Lawrence Bottorff ha scritto:
flipA :: (a -> b -> c) -> b -> a -> c flipA f x y = f y x
What is it specifically about currying that makes flipA possible?
I do not see how currying is involved here! Maybe when you pass a function to an higher order one?
flipB :: (a -> b -> c) -> b -> a -> c flipB f = \x y -> f y x
Also, with flipB, could someone explain the beta reduction? It looks like f is not being acted on, just passed along, Would it look more like this in lambda calculus?
Indeed `f` is not being acted on (i.e. it is «outside» of the lambda) (λx. λy. f y x) b a (λy. f y b) a beta f a b beta fully expressed with lambdas would be: (λf. λx. λy. f y x) g b a