Github user [alanjds] opened an issue asking to add a Tab button to the application for use with REPL. I didn't even know that the REPL offered tab completion before that. It was pretty straight forward to add a tab button and right away I could tell that it was possible to make it work because it was able to make suggestions about what I had typed. But to use it effectively was bit more tricky because sometimes it returns full strings and other times it only returns the ending part of the string, and other times it returns lists of available strings, so the app needs to behave correctly in all these cases. In the end I settled on reading the string out of the display text box. It's working pretty well but there are still some scenarios where the behavior is not great.
If you want to give it a try the debug apk in the repo has been updated to the new versions. Let me know how it goes if you do!