def iterator_key_result

bend-collections@1.0.0.0 · src/containers/balanced_search_tree.bend:423

import Base

423def iterator_key_result(~K: Data, ~V: Data, ~cmp: K -> K -> Cmp, r: Cursor<K, V, cmp> & Maybe<&2, Entry<K, V>>) -> Cursor<K, V, cmp> & Maybe<&2, K>:
424  match r:
425    case Tuple{cursor, None{}}:
426      (cursor, None{})
427    case Tuple{cursor, Some{Entry{k, v}}}:
428      (cursor, Some{k})