def split_left

bendtorch-core@0.1.0.0 · src/shape/index_proofs.bend:12

import Base
import bendtorch-core@0.1.0.0/src/shape/core.bend as Shape

12def split_left(+a: Nat, +b: Nat, +index: Shape.Fin(a)) -> {Shape.Fin.split(a, b, Shape.Fin.left(a, b, index)) == Inl{index} : Either<Shape.Fin(a), Shape.Fin(b)>}:
13  match a:
14    case 0n:
15      match index:
16    case 1n+p:
17      match index:
18        case Shape.FZero{}:
19          {==}
20        case Shape.FNext{+previous}:
21          %split_left(p, b, previous) : {Shape.Fin.split.step(p, b, Shape.Fin.split(p, b, Shape.Fin.left(p, b, previous))) == Shape.Fin.split.step(p, b, _) : Either<Shape.Fin(1n+p), Shape.Fin(b)>}
22          {==}