def base_append

bend-collections-laws-math@1.0.0.0 · proofs/lib/list.bend:136

import Base
import bend-collections-laws-math@1.0.0.0/spec/lib/common.bend as SC

136# Base List.append agrees with the specification append.
137def base_append(-A: Data, +xs: List<&2, A>, +ys: List<&2, A>) -> {List.append(&2, A, xs, ys) == SC.append(A, xs, ys) : List<&2, A>}:
138  match xs:
139    case Nil{}:
140      {==}
141    case Con{+h, +t}:
142      cons_cong(A, h, List.append(&2, A, t, ys), SC.append(A, t, ys), base_append(A, t, ys))