Is there a string math evaluator in .NET?

Question

If I have a string with a valid math expression such as:

String s = \"1 + 2 * 7\";

Is there a built in library/function in .NET that will p

Answer 1

Have you seen http://ncalc.codeplex.com ?

It's extensible, fast (e.g. has its own cache) enables you to provide custom functions and varaibles at run time by handling EvaluateFunction/EvaluateParameter events. Example expressions it can parse:

Expression e = new Expression("Round(Pow(Pi, 2) + Pow([Pi2], 2) + X, 2)"); 

  e.Parameters["Pi2"] = new Expression("Pi * Pi"); 
  e.Parameters["X"] = 10; 

  e.EvaluateParameter += delegate(string name, ParameterArgs args) 
    { 
      if (name == "Pi") 
      args.Result = 3.14; 
    }; 

  Debug.Assert(117.07 == e.Evaluate()); 

It also handles unicode & many data type natively. It comes with an antler file if you want to change the grammer. There is also a fork which supports MEF to load new functions.