/Prelude-v21.0.0/NonEmpty/head.dhall

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Retrieve the first element of the NonEmpty list

Examples

head Natural { head = 0, tail = [ 1, 2 ] } ≡ 0

Source

--| Retrieve the first element of the `NonEmpty` list
let NonEmpty =
./Type.dhall sha256:e2e247455a858317e470e0e4affca8ac07f9f130570ece9cb7ac1f4ea3deb87f
? ./Type.dhall

let head
: ∀(a : Type) → NonEmpty a → a
= λ(a : Type) → λ(xs : NonEmpty a) → xs.head

let example = assert : head Natural { head = 0, tail = [ 1, 2 ] } ≡ 0

in head