Why is font-lock needed for a mode based on Semantic CFG parser?

Hi list,

Please excuse me, if I'm asking something obvious, but this question
bothered me since I've red the guide for making a mode that uses
Semantic. It says that I need to handle font-lock on my own, which, as
far as I can understand uses parsing system based on regular
expressions. It feels self-defeating to have a real CFG parser with
proper syntax analysis and still rely on regular expressions for
coloring.

So, my question is: why, and if really, isn't it possible to employ
Semantic for syntax highlighting as well as completion / syntax
checking / navigation. Do I need font-lock mode for Semantic to work
(properly)? If I may guess: is this because during editing the edited
region may not be syntactically valid and it is hard / not possible /
too costly at the moment to deal with it using Semantic?

Thanks,

Oleg

------------------------------------------------------------------------------
Want fast and easy access to all the code in your enterprise? Index and
search up to 200,000 lines of code with a free copy of Black Duck
Code Sight - the same software that powers the world's largest code
search on Ohloh, the Black Duck Open Hub! Try it now.
http://p.sf.net/sfu/bds