mirror of
https://github.com/oliverbooth/X10D
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86 lines
2.9 KiB
Markdown
86 lines
2.9 KiB
Markdown
## X10D
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X10D (pronounced *extend*), is a .NET package that provides extension methods for numerous types. The purpose of this library is to simplify a codebase by reducing the need for repeated code when performing common operations. Simplify your codebase. Take advantage of .NET. Use extension methods.
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*(I'm also [dogfooding](https://www.pcmag.com/encyclopedia/term/dogfooding) this library, so there's that.)*
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### What are extension methods?
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Extension methods are a clever .NET feature that augment existing types with new functionality. They are defined as
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static methods in a static class, and are called as if they were instance methods on the type they are extending. Take,
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for example, the following code:
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```csharp
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public static class Program
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{
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public static void Main()
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{
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string str = "Hello, world!";
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Console.WriteLine(str.Reverse());
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}
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}
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public static class StringExtensions
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{
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public static string Reverse(this string str)
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{
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char[] chars = str.ToCharArray();
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Array.Reverse(chars);
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return new string(chars);
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}
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}
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```
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This will print `!dlrow ,olleH` to the console. The `Reverse` method is defined in the `StringExtensions` class, yet is
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called as if it were an instance method on the `str` variable, even though it's not.
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### Why use extension methods?
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Extension methods were introduced when LINQ was added to .NET. LINQ is a set of extension methods that provide a way to
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query, filter, and transform data. If you were to access LINQ's methods statically, you would have to write code like
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this:
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```csharp
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public static class Program
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{
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public static void Main()
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{
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int[] numbers = { 1, 2, 3, 4, 5 };
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IEnumerable<int> evenNumbers = Enumerable.Where(numbers, x => x % 2 == 0);
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IEnumerable<int> doubledNumbers = Enumerable.Select(evenNumbers, x => x * 2);
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int sum = Enumerable.Sum(doubledNumbers);
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Console.WriteLine(sum);
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}
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}
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```
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And if you wanted to one-line this, you'd have to write this:
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```csharp
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public static class Program
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{
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public static void Main()
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{
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int[] numbers = { 1, 2, 3, 4, 5 };
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Console.WriteLine(Enumerable.Sum(Enumerable.Select(Enumerable.Where(numbers, x => x % 2 == 0), x => x * 2)));
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}
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}
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```
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This is a lot of code to write, and it's not very readable. The nested method calls make it incredibly difficult to
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follow. However, because LINQ is implemented as extension methods, you can write the following code instead:
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```csharp
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public static class Program
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{
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public static void Main()
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{
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int[] numbers = { 1, 2, 3, 4, 5 };
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Console.WriteLine(numbers.Where(x => x % 2 == 0).Select(x => x * 2).Sum());
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}
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}
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```
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Because the methods are called as if they were instance methods on `IEnumerable<T>`, they can be chained together,
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making the code much more readable.
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X10D aims to provide these same benefits as LINQ, but for dozens of other types and for countless other use cases. |