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

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Returns True if the supplied function returns True for all elements in the List

Examples

all Natural Natural/even [ 2, 3, 5 ] ≡ False
all Natural Natural/even ([] : List Natural) ≡ True

Source

{-|
Returns `True` if the supplied function returns `True` for all elements in the
`List`
-}
let all
: ∀(a : Type) → (a → Bool) → List a → Bool
= λ(a : Type) →
λ(f : a → Bool) →
λ(xs : List a) →
List/fold a xs Bool (λ(x : a) → λ(r : Bool) → f x && r) True

let example0 = assert : all Natural Natural/even [ 2, 3, 5 ] ≡ False

let example1 = assert : all Natural Natural/even ([] : List Natural) ≡ True

in all