ansible/dhall/Prelude/Optional/length.dhall
2024-11-26 00:55:56 -05:00

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Text

{-|
Returns `1` if the `Optional` value is present and `0` if the value is absent
-}
let length
: ∀(a : Type) → Optional a → Natural
= λ(a : Type) →
λ(xs : Optional a) →
merge { Some = λ(_ : a) → 1, None = 0 } xs
let example0 = assert : length Natural (Some 2) ≡ 1
let example1 = assert : length Natural (None Natural) ≡ 0
in length