GtkSourceView Highlighting

Hey, I'm not sure if this has been addressed, future plans, or whatever, 
but...

It would be nice if GtkSourceView could handle multiple languages in a 
single file. This would be especially useful for web development where a 
single file might have PHP, HTML, CSS, and JavaScript all in a single 
file. If it could parse the document and apply the php.lang to code 
within php blocks, apply CSS withing <style> blocks, apply Javascript 
within <script> blocks, etc.

Has this been discussed?

Cheers,
- Micah Carrick