Objective-C implementation inspired by concepts introduced at WWDC 2015 Session 226 Advanced NSOperations.
Work in progress. Want to help? Please check the issues.
Original codebase has been written on Swift: download link.
Please note, that the original codebase had some bugs, so there is no guarantee that this objective-c port doesn't have them as well.
The most up-to-date implementation in Swift: https://github.com/pluralsight/PSOperations