using uCalcSoftware;

var uc = new uCalc();
using (var t = new uCalc.Transformer()) {
   // This rule will only match the standalone token 'rate', not 'exchange_rate'.
   t.FromTo("rate", "interestRate");

   var code = "var exchange_rate = 0.5; var rate = 0.1;";
   Console.WriteLine(t.Transform(code));
}