// C# Eval Expression

// Doc: https://eval-expression.net/my-first-evaluation

​

// @nuget: Z.Expressions.Eval

​

/*

## Use Option for Safe Mode

​

The [Safe Mode](/options#safemode) ensures that only members and types registered can be used for the expression.

​

To use safe mode, we recommend:

- A local or static context

- Unregistering all types first

- Limiting the maximum number of loops with the [MaxLoopIteration](/options#maxloopiteration) option

- Setting the `SafeMode` option to true

- Registering only what you want the user to be able to use

​

For example, we will demonstrate how easy it is to configure options in the C# Eval Expression library:

​

See more: https://eval-expression.net/my-first-evaluation

*/

​

using System;

using System.Collections.Generic;

using Z.Expressions;

​

public class Program

{

    public static void Main()

    {

        var evalContext = new EvalContext();

        evalContext.UnregisterAll();

        evalContext.MaxLoopIteration = 5;

        evalContext.SafeMode = true;

        evalContext.RegisterMember(typeof(System.Math));

        var r1 = evalContext.Execute("Math.Min(1, 2)");

        Console.WriteLine("1 - Result: " + r1);

        try

        {

            // `List` is no longer registered, so it cannot be used

            var r2 = evalContext.Execute("new List<int>()");

        }

        catch(Exception ex)

        {

            Console.WriteLine("Cannot use `List` exception: " + ex.Message);

        }

    }

}