Is there a way (if not consider it a feature request) to dynamically include a syntax in a syntax?

What I am getting at is here-docs and similar constructs that contain another syntax. For example it would be cool if for example in perl I could write:

print <<"text.xml.plist"; # some xml property list here text.xml.plist

and it would just apply the text.xml.plist syntax to the here-doc.

I know I can hard-code it in a 'meta' syntax, but that gets bothersome...

Gerd