Question

There are many algorithms to evaluate expressions, for example:

1. By Recursive Descent
2. Shunting-yard algorithm
3. Reverse Polish notation

Is there any way to evaluate any mathematical expression using C# .net reflection or other modern .net technology?

Answer 1

Further to Thomas’s answer, it’s actually possible to access the (deprecated) JScript libraries directly from C#, which means you can use the equivalent of JScript’s eval function.

using Microsoft.JScript;        // needs a reference to Microsoft.JScript.dll
using Microsoft.JScript.Vsa;    // needs a reference to Microsoft.Vsa.dll

// ...

string expr = "7 + (5 * 4)";
Console.WriteLine(JScriptEval(expr));    // displays 27

// ...

public static double JScriptEval(string expr)
{
    // error checking etc removed for brevity
    return double.Parse(Eval.JScriptEvaluate(expr, _engine).ToString());
}

private static readonly VsaEngine _engine = VsaEngine.CreateEngine();