def Decimal.rescale

bend-kit-bignum@0.1.0.0 · decimal.bend:203

import Base

203# The same value at scale t, or None when that would drop a nonzero digit:
204# rescale(1.5, 2n) is 1.50; rescale(1.25, 1n) is None, never 1.2 or 1.3.
205def Decimal.rescale(d: Decimal, +t: Nat) -> Maybe<&2, Decimal>:
206  match d:
207    case Decimal{u, +s}:
208      Decimal.rescale.if(Nat.is_le(s, t), u, s, t)