def Format.frac.start
import bend-time-lib@0.4.0.1/format.bend as Formatimport Base
166def Format.frac.start(
167 s: String, off: Nat
168) -> Result<&2, &2, Format.Error, Format.FracP>:
169 match s:
170 case SNil{}:
171 Fail{BadFraction{off}}
172 case SCon{+h, t}:
173 Format.frac.go(t, 9n, Char.is_digit(h), h, 0, off, 0n)