C# Eval Expression String Extensions Support

The Z.Expressions.Eval library extends the String class with methods like Execute & Compile to execute and compile C# expression. The string extensions use the default context to execute and compile expressions.

The following example uses the Execute extension method of the string class.

public static void Example1()
{
    string expression = "a*2 + b*3 - 3";
    int result = expression.Execute<int>(new { a = 10, b = 5 });
    Console.WriteLine("{0} = {1}", expression, result);
}

Let's consider another example where the Execute extension method of the string class takes a dictionary object as a parameter.

public static void Example2()
{
    string expression = "a*2 + b*3 - 3";

    var values = new Dictionary<string, object>()
    {
        { "a", 10 },
        { "b", 5 }
    };

    int result = expression.Execute<int>(values);
    Console.WriteLine("{0} = {1}", expression, result);
}

The following example shows how to compile an expression to a delegate using the Execute extension method.

public static void Example3()
{
    string expression = "a*2 + b*3";
    var compiled = expression.Compile<Func<int, int, int>>("a", "b");
    int result = compiled(10, 15);

    Console.WriteLine("{0} = {1}", expression, result);
}