I think LISP is an excellent fit for the poor text input facilities that touchscreens offer.<p>Structuring, wrapping an navigating code bodies is very easy, thanks to the simple syntax structure of the language, and you need very few uncommon characters (parens, quotes and dashes being the most common ones), buttons for which would easily be fitted into the touchscreen UI.<p>auto-completion is also pretty simple, since most of the time the first entry of a non-quoted list will be a function listed somewhere near in a defun, and other entries will often be an identifier nearby. Other cases, such as constants, new identifiers or unknown functions, will need more input work from the user, but this is still feasible.