I started out with C# since then I’ve learned other languages and one of my favorites is Golang.
When I was reading the release notes from C# 8 I saw the new using declaration and through it was awesome… I also realized it could be misused to give C# the defer keyword from Golang.
Whats defer in Golang do?
defer in Golang lets you define a function that will get run when the code block exits.
The example below will print:
hello world
Code: Try it out here
package main
import "fmt"
func main() {
defer fmt.Println("world")
fmt.Println("hello")
}
I’m a big fan of this approach as I think it’s clearer to read than the standard try finally pattern as it lets you put the cleanup code directly below the code which is making the mess like:
f := createTempFile("/tmp/defer.txt") defer deleteTempFile(f) writeFile(f) // here the `deleteTempFile` method gets called
How can we do this in C# 8 with the new using syntax?
Well now because using var x = new thing()exists you can write a simple class called defer which runs a function when the current method exits, just like in golang
The interesting thing is that as a using statement generates a try finally under the covers these defer functions will still run if an exception is thrown.
The example below will print:
Hello World! Defer 2 Defer 1 Exception thrown: It's all one wrong
Code:
Should you do this? Well that’s kinda up to you, I don’t think it’s super nasty but I’ve not used this in anger so probably worth testing out a bit before going all out.
