If you want to convert your Objective_Code to Swift this could be very useful ObjCConverter.
There is also an online converter if you want to try before you buy
The latest post on the Swift blog highlights interactive playgrounds.
Xcode 7.3 beta 3 adds interactive iOS and OS X playgrounds that allow you to click, drag, type, and otherwise interact with the user interfaces you code into your playground. These interfaces react just as they would within a full application. Interactive playgrounds help you to quickly prototype and build your applications, and simply provide another great way to interact with your code.