xml build a list of all elements

Hello, 

I have a postgresql database table with xml data. 
What I need is a list of all elements and attributes.
Example:
<area>
  <sub>
   <sub2 attr='1'>comment</sub2>
   <sub2 attr='2'>comment</sub2>
  <sub>
</area>

The result should be:
/area
/area/sub
/area/sub/sub2
/area/sub/sub2@attr
/area/sub/sub2
/area/sub/sub2@attr

or distinct (it's enough)
/area
/area/sub
/area/sub/sub2
/area/sub/sub2@attr

Is there a postgresql function to build this list?

Franz