def digit.if

lawful-fields@0.1.1.0 · defs.bend:32

import Base

32def digit.if(+x: U32, ok: Bool) -> Maybe<&2, Nat>:
33  match ok:
34    case True{}:
35      Some{Nat.sub(U32.to_nat(x), 48n)}
36    case False{}:
37      None{}