I'm currently exploring the latest Xcode Beta, and while doing so I'm watching some related WWDC videos. According to this one(around 33rd minute) you can now have a quick code generation macro(similar to Eclipse and AS).
I'm unable to understand how to use this. Right after this we have a talk about xcode extension so it is possible this to be an extension however it's not clear to me - is it possible to have such feature with Xcode 8 beta?
In order to use this functionality or any Xcode Extensions on macOS 10.11 El Capitan, you need to follow the instructions in the Xcode 8 release notes:
This is currently necessary to tell the older operating system about the new Xcode Extension mechanism. It should not be necessary on any macOS Sierra beta.