ProofBase.head_or: def of lawful-arrays@0.1.0.0
Import: import lawful-arrays@0.1.0.0/proof_base.bend as ProofBase
Lines 434-439 of lawful-arrays@0.1.0.0/proof_base.bend: https://jend.leeeet.dev/read.txt?path=lawful-arrays@0.1.0.0/proof_base.bend&start_line=434&end_line=439

import Base

def head_or(-A: Data, +d: A, xs: List<&2, A>) -> A:
  match xs:
    case Nil{}:
      d
    case h <> t:
      h

Uses (1):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List