         }
         else {
             assert(false, "what?")
+            return SplitResult.singleCurve(curve: self) // TODO: fix
         }
     }
 

        }
        else {
            assert(false, "what?")
        }
    }
    

                        return v.z
                    default:
                        assert(false, "nope!")
                        return 0.0 // TODO: fix
                }
            }
            var p: [BKFloat] = self.dpoints[0].map(mfn)
