I wonder how a mobile-first programming language / environment would be like.
I guess something with as little punctuation as possible, so that you wouldn't need that many keys. A good autocomplete would probably be essential too. Would text still be the prefered input method? Is there something better suited to touchscreen input?
What about code display? I guess the "lots of little functions" style, which would probably allow for the easiest navigation on a tiny screen. Maybe collapsable/expandable function sections, like in WorkFlowy?
Interesting question. There's probably a tradeoff at play here between 'easy to input' and 'easy to read'.
As nothing more than a random guess, I believe a lisp could be appropriate here. Highly flexible syntax means it's easy to make a custom way to input code that works for a phone (you could imagine that touching a form makes a dialog appear or something like that. I'm terrible at UIs), and homoiconicity helps reconciling the input UI and code as it's written.
Plus, lisps are fun! :)
Fructure might be nice on a phone! Currently makes heavy use of keyboard shortcuts but I bet it could be adapted to a touchscreen.