ProofWord.wdiff: def of lawful-words@0.1.0.0
Import: import lawful-words@0.1.0.0/proof_word.bend as ProofWord
Lines 918-932 of lawful-words@0.1.0.0/proof_word.bend: https://jend.leeeet.dev/read.txt?path=lawful-words@0.1.0.0/proof_word.bend&start_line=918&end_line=932

import Base

# The lowest bit where two words differ (0 if they are equal).
def wdiff(n: Nat, a: Word(n), b: Word(n)) -> Nat:
  match n:
    case 0n:
      0n
    case 1n+p:
      match a b:
        case WCon{False{}, at} WCon{False{}, bt}:
          1n+wdiff(p, at, bt)
        case WCon{False{}, at} WCon{True{}, bt}:
          0n
        case WCon{True{}, at} WCon{False{}, bt}:
          0n
        case WCon{True{}, at} WCon{True{}, bt}:
          1n+wdiff(p, at, bt)

Uses (4):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Word
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Word.Con