def must

yaml-for-bend@0.1.1.0 · core.bend:112

import Base
import yaml-for-bend@0.1.1.0/value.bend as V

112def must(m: Maybe<&2, V.Yaml>, +tag: String, +s: String) -> Result<&2, &2, String, V.Yaml>:
113  match m:
114    case Some{v}:
115      Done{v}
116    case None{}:
117      Fail{"found a value that isn't a " ++ tag ++ ": " ++ s}