def mantissa
import bend-toon-codec@0.1.0.0/src/num.bend as Numimport Base
182def mantissa(+d: String) -> String:
183 match d:
184 case SNil{}:
185 "0"
186 case SCon{c, t}:
187 match t:
188 case SNil{}:
189 SCon{c, SNil{}}
190 case _:
191 SCon{c, SCon{'.', t}}