Defs.digit.if: def of lawful-fields@0.1.1.0
Import: import lawful-fields@0.1.1.0/defs.bend as Defs
Lines 32-37 of lawful-fields@0.1.1.0/defs.bend: https://jend.leeeet.dev/read.txt?path=lawful-fields@0.1.1.0/defs.bend&start_line=32&end_line=37

import Base

def digit.if(+x: U32, ok: Bool) -> Maybe<&2, Nat>:
  match ok:
    case True{}:
      Some{Nat.sub(U32.to_nat(x), 48n)}
    case False{}:
      None{}

Uses (6):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.sub
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.to_nat