Language extension (better than TextMate)

With a TextMate bundle you could include patterns from another language into another. This was very limiting.

It would be nice if you had a "extended language" type that would use a specified language but recursively override elements in that language. So this would go beyond simply including the patterns. A big reason for this is template systems... Smarty is built into TextMate's HTML bundle and it shouldn't be. Ruby includes the HTML bundle, but has to re-specify certain things. With a language extension you could have a pattern added before or after a languages pattern based on its name.

Also with embedding languages make this work a little better than importing patterns. If I'm working in an HTML file and have script tags it should be the Javascript language while inside those tags (not just including the patterns, if that makes sense).