def checked_sub
bend-collections-laws-math@1.0.0.0 · proofs/math/typed/fix64.bend:109
import bend-collections-laws-math@1.0.0.0/proofs/math/typed/fix64.bend as Fix64
import Base
import bend-collections-laws-math@1.0.0.0/spec/math/generic.bend as SG
import bend-collections-laws-math@1.0.0.0/spec/math/fixed.bend as SF
import bend-collections-laws-math@1.0.0.0/src/math/u64.bend as WU
import bend-collections-laws-math@1.0.0.0/src/math/fixed.bend as F
109def checked_sub(+a: WU.U64, +b: WU.U64) -> SF.CheckedSub.value(~WU.U64, ~SG.u64_val, ~F.u64_checked_sub, a, b):
110 csub(a, b, Nat.is_le(SG.u64_val(b), SG.u64_val(a)), {==})