/Prelude-v21.1.0/Optional/all.dhall

Copy path to clipboard

Returns False if the supplied function returns False for a present element and True otherwise:

Examples

all Natural Natural/even (Some 3) ≡ False
all Natural Natural/even (None Natural) ≡ True

Source

{-|
Returns `False` if the supplied function returns `False` for a present element
and `True` otherwise:
-}
let all
: ∀(a : Type) → (a → Bool) → Optional a → Bool
= λ(a : Type) →
λ(f : a → Bool) →
λ(xs : Optional a) →
merge { Some = f, None = True } xs

let example0 = assert : all Natural Natural/even (Some 3) ≡ False

let example1 = assert : all Natural Natural/even (None Natural) ≡ True

in all