def non_empty

bend-collections@1.0.0.0 · src/containers/intrusive_doubly_linked_list.bend:45

import Base
import bend-collections@1.0.0.0/src/containers/internal/intrusive_list.bend as Impl

45# O(1) nonempty-root query.
46def non_empty(~S: Type, ~N: Data, ~H: Data, ~get_head: S -> H -> S & Maybe<&2, N>, s: S, +h: H) -> S & Bool:
47  Impl.non_empty(~S, ~N, ~H, ~get_head, s, h)