We are using development boards from www.PyCom.io (PyTrack, PySense, FiPy's...) to quickly test out new IoT-ideas ... and it work:ish quite well ...
One idea I have been pondering about is if it possible to port the Swift language to run on the Espressif-ESP32 that the PyCom boards them self run on.
To run MicroPython: https://github.com/pycom/pycom-micropython-sigfox
So I was wondering, if it would be possible ... for fun sake ... to port the Swift-language to it?
And I'm thinking of https://github.com/apple/swift-lldb as it runs a REPL ... which looks to be the same thing they've done with porting MicroPython to it ... as it runs a REPL ...