It's more general than for just editing code (a code editor is just all I've built so far): editing English documents by manipulating the units: paragraph, sent

It's more general than for just editing code (a code editor is just all I've built so far): editing English documents by manipulating the units: paragraph, sentence, clause/phrase, word, character -- is the primary application I see for it (Unfortunately I didn't think of this until far into the code editor :)