Map.size: def of Base
Import: import Base
Lines 3053-3060 of Base/base.bend: https://jend.leeeet.dev/read.txt?path=Base/base.bend&start_line=3053&end_line=3060

import Base

def Map.size(a, -V: Kind(a), m: Map<a, V>) -> Nat:
  match m:
    case MTip{}:
      0n
    case MLeaf{k, v}:
      1n
    case MNode{pos, lo, hi}:
      Nat.add(Map.size(a, V, lo), Map.size(a, V, hi))

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Map
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.add