[plt-scheme] Maintaining self-references in Planet packages

As a Planet package developer, I've occasionally had to make my
software refer to itself.  For instance, Scribble documentation
presents a module path by which to import or install the package.
This raises the difficult issue of how to refer to the appropriate
version of a package within itself, without having to manually update
that version number on each release.  I have developed several macros
to help solve this problem, released them as part of a Planet package,
and described them in a PLT Blog post:

http://blog.plt-scheme.org/2009/03/maintaining-self-references-in-planet.html

I hope some of you find this helpful!

-- 
Carl Eastlund