You don’t need Ctrlr for that, you need lua (the lua language interpreter called luac that is part of the Lua distro for any platform).
For each platform doing MIDI is different so what you need is a cross-platform way to access MIDI, and that method needs to be written for Lua for example (quick google search) http://www.pjb.com.au/comp/lua/MIDI.html
Lua is just a small part of Ctrlr, it’s not the other way aroung (Ctrlr is part of Lua, or is an API for Lua)