Small parts of Genius Scan are written in Swift. It's working fine.
In theory it's nice to work with, as it forces you to think everything more carefully and consider all error/nullable cases. In practice, integration with XCode is still full of bugs, code completion is crashing all the time, Swift classes show up as missing symbols in Objective-C (but the project compiles fine)... So, it's a bit painful and it slows down the development process.
We will keep it to very small and well-defined pieces of code for now. It's good to learn about it, but it's not productive.
In theory it's nice to work with, as it forces you to think everything more carefully and consider all error/nullable cases. In practice, integration with XCode is still full of bugs, code completion is crashing all the time, Swift classes show up as missing symbols in Objective-C (but the project compiles fine)... So, it's a bit painful and it slows down the development process.
We will keep it to very small and well-defined pieces of code for now. It's good to learn about it, but it's not productive.