Tonight I started working on some Shortcode processing in WordPress. This is an historically nasty problem because the Shortcode syntax and parsing is wildly dynamic.

• Shortcode syntax is only technically recognized for shortcodes registered at the time of parsing. This means that there is not a general Shortcode grammar.
• Whether a shortcode has “content,” meaning whether it expects a closing tag, depends on whether the closing tag exists in the post.

This is a problem that has plagued me for years and I have generally just ignored. There’s an open Core issue in Trac for changing some shortcode parsing (#50683), and I have thought a lot about it.

But I think there is more to explore, and more to gain. Maybe this goes nowhere, but keep your eyes open for it.