Would "root" allow for captures?

[Michael Shadle]

i'd like to do something like:

server {
   listen 80;
   server_name *.user.foo.com;
   root /home/user/web/$1;
}

this would be basically required too:

server {
   listen 80;
   server_name *.user.foo.com;
   root /home/user/web/$1;
   if ($1 == 'something) {
      require include.conf;
   }
}

it would be nice if i could assign "user" as a variable too. however,
that would be a double bonus.

i think alias allows captures, but i would need to define
DOCUMENT_ROOT then as well.

ideas?