[tommorris]

The visual editor uses a new parser, Parsoid, which has been implemented separately in node.js (iirc). That may be the answer...

[gnosygnu]

Yup. It also has its own DOM, rather than continuously adding to one string and repeatedly running regex's on it (which is what MediaWiki does today).

I was already pretty far along with my own parser before Parsoid was usable though. (and my parser has its own DOM / hooks)

[tommorris]

MediaWiki is such an astoundingly fugly piece of software.