using System;

using System.Text.RegularExpressions;

using NCalc;

​

public class Program

{

​

    public static void Main()

    {

        var equation = "Shaft_RPM = [OPC.MonCh.6230S01] * (-1) + WinDir - Asin(WinDir)";

        var formulaParts = Regex.Split(equation, "(?<=^[^=]*)=", RegexOptions.None);

        var lhs = formulaParts[0];

        var rhs = formulaParts[1];

        var result = new Expression(rhs);

        var matches = Regex.Matches(rhs, @"[a-zA-Z0-9_]+");

        foreach(Match m in matches)

        {

            Console.WriteLine(m.Value);

        }

        Console.WriteLine("----------------------");

        //Console.WriteLine(result.Parameters.Values);

        var parsed = string.Join(Environment.NewLine, result.GetParameterNames());

        Console.WriteLine(parsed);

    }

}