// C# Eval Expression

// Doc: https://eval-expression.net/eval-compile

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// @nuget: Z.Expressions.Eval

​

/*

### The code

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This part is exactly like the [Execute Method](/eval-execute#the-code).

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You can provide the code to compile in 3 different ways:

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1. **Instance method:** `context.Compile(code)`

2. **Static method:** `Eval.Compile(code)`

3. **Extension method:** `"code".Compile`

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1 - In the case of the **instance method** (`context.Compile(code)`). First, you create a new instance of the [EvalContext](/eval-context), and then you can use the `Compile` method from the context created:

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2 - In the case of the **static method** (`Eval.Compile(code)`), you can directly call the static `Eval.Compile` method, which uses a global context under the hood: 

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3 - In the case of the **extension method** (`"code".Compile`), you can directly call the `Compile` method that extends the string type, which uses a global context under the hood:

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One of the major differences is whether you want to create a new instance of the [EvalContext](https://eval-expression.net/eval-context) or use the global context (an instance stored in a static variable).

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We explain the answer more detail in the [EvalContext](https://eval-expression.net/eval-context) documentation, but in short:

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- If you need to customize the context for this specific compilation, **you should** use an instance context

- If you don't need to customize the context for this specific compilation, **you can** use the global context

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See more: https://eval-expression.net/eval-compile

*/

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using System;

using System.Collections.Generic;

using Z.Expressions;

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public class Program

{

    public static void Main()

    {

        // 1. **Instance method:** `context.Compile(code)`

        {

            // CREATE a new instance of EvalContext

            var context = new EvalContext();

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            // USE the `Compile` method from the context created

            var compiledList1 = context.Compile<Func<List<int>>>("new List<int>() { 1, 2, 3 };");

            var list1 = compiledList1();

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            FiddleHelper.WriteTable(list1);

        }

        // 2. **Static method:** `Eval.Compile(code)`

        {                   

            // CALL the static `Eval.Compile` method

            var compiledList2 = Eval.Compile<Func<List<int>>>("new List<int>() { 1, 2, 3 };");

            var list2 = compiledList2();

            FiddleHelper.WriteTable(list2);

        }

​

        // 3. **Extension method:** `"code".Compile`

        {

            // CALL the `Compile` method that extends the string type

            var compiledList3 = "new List<int>() { 1, 2, 3 };".Compile<Func<List<int>>>();

            var list3 = compiledList3();

            FiddleHelper.WriteTable(list3);

        }

    }

}

​

​