def rev_rev

bend-collections-laws-math@1.0.0.0 · proofs/lib/list.bend:159

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

159def rev_rev(-A: Data, +xs: List<&2, A>) -> {List.reverse(&2, A, List.reverse.go(&2, A, xs, Nil{})) == xs : List<&2, A>}:
160  Equal.trans(List<&2, A>, List.reverse.go(&2, A, List.reverse.go(&2, A, xs, Nil{}), Nil{}), SC.append(A, xs, Nil{}), xs, rev_go_twice(A, xs, Nil{}, Nil{}), append_nil(A, xs))