using uCalcSoftware;

var uc = new uCalc();
// Get the transformer that pre-processes expressions.
var t = uc.ExpressionTransformer;

// Define a rule to find "X in to cm" and replace it with the calculated value.
// Note: 'val' is captured as text and must be converted to a number with Double().
t.FromTo("{@Number:val} in to cm", "({@Eval: Double(val) * 2.54})");

// Use the new syntax directly in an expression.
Console.WriteLine(uc.EvalStr("10 in to cm"));