func roundFloat64(x exact.Value) exact.Value {
f, _ := exact.Float64Val(x)
if !math.IsInf(f, 0) {
return exact.MakeFloat64(f)
}
return nil
}
func fitsFloat64(x exact.Value) bool {
f, _ := exact.Float64Val(x)
return !math.IsInf(f, 0)
}