For a function f :: a -> b -> c is it possible to write a function g, so that the call (f g) has type c?
Specifically, if I have a data Type data Example = Example String String the constructor Example is of Type String -> String -> Example, so is there a way for a function to generate both arguments "at once" without having to return a tuple and separating it or something similar?
I tried having g as g :: a -> b, but that doesn't work (and doesn't make sense, because for f there is a value for a necessary and g doesn't encode have any value for a), but from the typing alone, this seems to be the only reasonable choice as a type of g.
Nope. You could pass f to another function, though – maybe g itself, maybe something else like uncurry.
ghci> :t uncurry f
uncurry f :: (a, b) -> c
ghci> let g = ("foo", 5)
ghci> uncurry f g
ghci> let g f = f "foo" 5
ghci> g f