How should tag coloring be done

[lassik]

Currently bbcode-mode only colors matching pairs of opening/closing tags. It doesn't color orphaned opening or closing tags at all (i.e. an opening tag without a matching closing tag or vice versa). This can be quite confusing to newcomers since the behavior is different from popular Emacs modes like xml-mode, html-mode and web-mode, all of which color orphaned tags as well as properly paired ones. (xml-mode goes a step further and colors orphaned closing tags in red to highlight that there's a syntax error, but that's tricky to do.)

As a related issue, bbcode-mode tries to implement tag pair matching using a regexp. This does not work properly with nested tags - in particular, nested [quote]s are problematic. It's very difficult if not impossible to properly parse nested structures using regexps.

In light of these points, I'd like to propose that the font-lock patterns should simply match individual opening/closing tags and not worry about pairing them up. This would make bbcode-modes font-lock behavior consistent with existing popular markup modes and would make the font-lock patterns much simpler to implement as well. What do you think?

[lassik]

#7 seems related

[lassik]

I see that when typing [b]foo[/b] the whole text is bolded which is nice. web-mode doesn't do that. html-mode seems like the best of both worlds: orphaned tags are colored and the foo part in <b>foo</b> is also bolded :) But it's not too ambitious: the foo part in <b><a href="x">foo</a></b> is not bolded. Maybe we could try going for this level of sophistication.