Kind/book/BBT.get.kind2
2024-02-20 17:08:37 -03:00

17 lines
562 B
Plaintext

BBT.get
: ∀(K: *)
∀(V: *)
∀(cmp: ∀(a: K) ∀(b: K) Cmp)
∀(key: K)
∀(map: (BBT K V))
(Maybe V)
= λK λV λcmp λkey λmap
let P = λx(Maybe V)
let bin = λ_size λnext.key λnext.val λnext.lft λnext.rgt
let P = λx ∀(cmp: ∀(a: K) ∀(b: K) Cmp) ∀(key: K) (Maybe V)
let ltn = λcmp λkey (BBT.get K V cmp key next.lft)
let eql = λcmp λkey (Maybe.some V next.val)
let gtn = λcmp λkey (BBT.get K V cmp key next.rgt)
((~(cmp key next.key) P ltn eql gtn) cmp key)
let tip = (Maybe.none V)
(~map P bin tip)