using uCalcSoftware;

var uc = new uCalc();

static void MyAreaCallback(uCalc.Callback cb) {
   var length = cb.Arg(1);
   var width = cb.Arg(2);
   cb.Return(length * width);
}


// The signature is defined, but the logic is provided by 'MyAreaCallback'.
uc.DefineFunction("Area(x, y)", MyAreaCallback);
Console.WriteLine(uc.Eval("Area(3, 4)"));