/Prelude-v19.0.0/Optional/map.dhall
Copy path to clipboardTransform an Optional
value with a function
Examples
map Natural Bool Natural/even (Some 3) ≡ Some False
map Natural Bool Natural/even (None Natural) ≡ None Bool
Source
--| Transform an `Optional` value with a function
let map
: ∀(a : Type) → ∀(b : Type) → (a → b) → Optional a → Optional b
= λ(a : Type) →
λ(b : Type) →
λ(f : a → b) →
λ(o : Optional a) →
merge { Some = λ(x : a) → Some (f x), None = None b } o
let example0 = assert : map Natural Bool Natural/even (Some 3) ≡ Some False
let example1 = assert : map Natural Bool Natural/even (None Natural) ≡ None Bool
in map