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elm

Multivariate function composition

Let's consider the following:

f: Int -> Int -> Int -> Int
f a b c = a + b + c

g: Int -> Int
g x = x * 2

now, I'd like to create a composed function like 

f(g(a), g(b), g(c))

how to use << and >> operators to achieve that? Is it even possible to compose multivariadic functions?

Solution

  • Multivariadic does not really exist in Elm. Best I can suggest is 

    f : Int -> Int -> Int -> Int
f a b c =
    [ a, b, c ] |> List.map ((<|) g) |> List.sum


g : Int -> Int
g x =
    x * 2

    Note that you had an error in the type signature for g