I do like the idea, but it doesn't seem to support some expected features.
Like <esc>:5d doesn't delete line #5. I get "Not an editor command"
Edit: Looked into it, and it's using the Ace Editor[1] with vim key bindings. Which seems like an odd choice for a Vim tutor, since Ace doesn't really try to be a true Vim workalike.
Implementing a full vi clone seems like a nightmare — the POSIX specification makes me lose hope in humanity :) For instance, what does :delep parse to? I would never have guessed that it was the :delete command with the "p" flag (because :delete p deletes into "p).
Like <esc>:5d doesn't delete line #5. I get "Not an editor command"
Edit: Looked into it, and it's using the Ace Editor[1] with vim key bindings. Which seems like an odd choice for a Vim tutor, since Ace doesn't really try to be a true Vim workalike.
[1] https://ace.c9.io/