I just wanted to comment here that termux is amazing. I do most of my non-work-hours coding in it, using vim. There are some C projects which are difficult to compile in termux, including ruby. But the termux packaging team usually takes care of that, so I just use the termux packaged ruby and it works perfectly. (I've done most of my `net-imap` work in termux.)
And you'll want an alternate keyboard for coding. Something with quick access to all of the symbols. I personally use MessagEase, but there are other more "normal" keyboards.
Please note: the version on the Google Play store is old and busted. You need to get working versions from F-Droid.