def append_assoc

qasim-bend-kit@0.1.0.2 · proof/JSON_ListProof.bend:9

import Base

9def append_assoc(-A: Data,
10                 +xs: List<&2, A>,
11                 +ys: List<&2, A>,
12                 +zs: List<&2, A>) -> {List.append(&2, A, List.append(&2, A, xs, ys), zs) == List.append(&2, A, xs, List.append(&2, A, ys, zs)) : List<&2, A>}:
13    match xs:
14        case Nil{}: {==}
15        case h <> t:
16            Equal.cong(List<&2, A>, List<&2, A>, q => h <> q,
17                List.append(&2, A, List.append(&2, A, t, ys), zs), List.append(&2, A, t, List.append(&2, A, ys, zs)), append_assoc(A, t, ys, zs))