Use using keyword to emulate Golang's defer keyword in C#
Get Started
$ dotnet add package DeferReadme
Defer
This repository provides IDeferable to emulate Golang's defer keyword in C#.
Installing
The package is available on NuGet. To install, run:
dotnet add package Defer
Build Status
Usage
- Usage of
Deferable
// Deferable.Defer
Console.WriteLine("Hello, World!");
using (Deferable.Defer(() => Console.WriteLine("Goodbye, World!")))
{
Console.WriteLine("Do something");
}
// output:
// Hello, World!
// Do something
// Goodbye, World!
- Usage of
Deferable<T>
// Deferable<T>
int status = -1;
Console.WriteLine("init status: " + status);
using (Deferable<int>.Defer(value => status = value, initValue: 1, deferValue: 0))
{
Console.WriteLine("doing something status: " + status);
}
Console.WriteLine("after defer status: " + status);
// output:
// init status: -1
// doing something status: 1
// after defer status: 0
- Usage of
BooleanDeferable
// BooleanDeferable
bool flag = default;
Console.WriteLine("init flag: " + flag);
using (BooleanDeferable.Defer(value => flag = value))
{
Console.WriteLine("doing something flag: " + flag);
}
Console.WriteLine("after defer flag: " + flag);
// output:
// init flag: False
// doing something flag: True
// after defer flag: False
- Usage of
RefDeferable<T>
// RefDeferable<T>
// Only applicable for .NET Standard 2.1, .NET Core 3.0, or later versions
double value = -1d;
Console.WriteLine("init value: " + value);
using (RefDeferable<double>.Defer(ref value, 0d, 1d))
{
Console.WriteLine("doing something value: " + value);
}
Console.WriteLine("after defer value: " + value);
// output:
// init value: -1
// doing something value: 0
// after defer value: 1
Comparison
Comparison with Go's
defer
In Go, defer is a keyword used to ensure that a function call is performed later in a program's execution, usually for purposes of cleanup.
fmt.Println("Hello, World!")
defer fmt.Println("Goodbye, World!")
fmt.Println("Do something")
In C#, using this library, you can achieve similar behavior with Deferable.Defer and the using statement.
Console.WriteLine("Hello, World!");
using IDeferable defer = Deferable.Defer(() => Console.WriteLine("Goodbye, World!"));
Console.WriteLine("Do something");
Both snippets output:
Hello, World!
Do something
Goodbye, World!