This will be a //new// editor, not a modification to the existing wikitext editor, because we want to avoid suddenly disrupting editors and breaking all existing gadgets.
MVP (for initial release as a Beta Feature) is described in more detail at {T141149}.
High importance:
[ ] Section editing
[ ] Desktop, tablet and mobile-suitable (dynamic/responsive)
Nice-to-haves:
[ ] Syntax highlighting
[ ] Code folding
A rough //mockup// is [[http://nirzar.github.io/prototypes/ve/switch/wikitext/wikitext.html|here]]. To see the wikitext editor, click the brackets icon in the top-right corner.
A rough **demo video** as of mid-May 2016 is [[ https://www.youtube.com/watch?v=jgd2ZHOZGBE ]].
You can see it in action at https://visualeditor-test.wmflabs.org/wiki/Wiki_markup?veaction=editsource
See also: [[ https://www.mediawiki.org/wiki/2017_wikitext_editor | mediawiki.org page ]]