I’m in the process of creating a plugin for this, using a naïve (but hopefully effective) pattern matching approach.
My main doubt is actually about the UI, though. It seems Discourse currently has at least 3 (maybe more?) idioms for alerting users before posting:
- Yellow overlay on top of rendered markdown. Dismissible, doesn’t prevent posting. Example: welcome message for first couple of posts. Least disruptive.
- Orange/red tooltip-like prompt. Prevents posting and jiggles if you try to post before fixing the problem. Example: “post too short” message.
- Modal dialog box. Prevents posting. Example: “your post looks like gibberish” message. Most disruptive.
I don’t think the modal is the right tool, as the message will need to be at least a couple of paragraphs long. Then again, the yellow overlay seems too easy to ignore. Possibly a combination of yellow overlay and orange jiggly tooltip could work?
Ideally, it’d also be permanently dismissible (“don’t show me this again”) to avoid annoying power users who intentionally do funky things with their markup that might otherwise trigger the pattern matcher.
Anyone have any thoughts? I’m open to other UI idioms as well, as long as they’re consistent with the general Discourse look and feel.