def Map.has

Base · base.bend:2902

2902def Map.has(-a: Quant, -V: Kind(a), m: Map<a, V>, key: String) -> Map<a, V> & Bool:
2903  match m:
2904    case MTip{}:
2905      (MTip{}, False{})
2906    case MLeaf{k, v}:
2907      Map.has.leaf(a, V, v, String.cmp(key, k))
2908    case MNode{+pos, lo, hi}:
2909      Map.has.go(a, V, MNode{pos, lo, hi}, Map.bit(key, pos))