C# Eval - My First Option - Use option to add method

CSharp · Console

/Program.cs

// C# Eval Expression
// Doc: https://eval-expression.net/my-first-option

// @nuget: Z.Expressions.Eval

/*
## Use Option to Add Method

In the C# Eval Expression library, you can add your own method.

If you can define the method in a non-dynamic way, you should always prefer to [register your method](/register-unregister) instead of creating it dynamically. Registered methods are faster and more secure.

In this first example, we’ll create a simple custom method called `MinPlusOne` that returns the minimum value between two numbers and adds one:

https://dotnetfiddle.net/4VXupA

In this second example, we go one step further. We’ll create a more advanced method dynamically, where the logic (formula) is provided by the user. This is useful when you want to inject a user-defined expression directly into a method.

https://dotnetfiddle.net/ZlZjx4

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

using System;
using System.Collections.Generic;
using Z.Expressions;

public class Program
{
	public static void Main()
	{
		string userInputFormula = "A == B || A == -1 || B == -1";
		
		var evalContext = new EvalContext();	
		
		evalContext.AddMethod($$"""public bool IsEqualsCustom(int A, int B) { return {{userInputFormula}}; }""");

		Console.WriteLine(evalContext.Execute<bool>("IsEqualsCustom(1, 1)")); 
		Console.WriteLine(evalContext.Execute<bool>("IsEqualsCustom(1, 2)")); 
		Console.WriteLine(evalContext.Execute<bool>("IsEqualsCustom(1, -1)")); 
	}
}