// value(lo) to value(hi-1)
protected static Value grind(RCvalue args, Operation op, int lo, int hi) throws EvalException {
switch (hi - lo) {
case 0:
return new PolygonValue(
(RCvalue) (RCvalue.factory().create(new Value[] {}, true))); // empty
case 1:
return args.value(lo); // one
case 2:
Value result = op.op((PolygonValue) (args.value(lo)), (PolygonValue) (args.value(hi - 1)));
return result; // two
default:
int mid = (lo + hi + 1) / 2; // split
Value v0 = grind(args, op, lo, mid);
Value v1 = grind(args, op, mid, hi);
result = op.op((PolygonValue) (v0), (PolygonValue) (v1));
return result;
}
}
