Algorithm::Dependency is a framework for creating simple read-only 
dependency hierarchies, where you have a set of items that rely on other 
items in the set, and require actions on them as well.

Despite the most visible of these being software installation systems like 
the CPAN installer, or debian apt-get, they are useful in other 
situations. This module intentionally uses implementation-neutral words, 
to avoid confusion.

WWW: http://search.cpan.org/dist/Algorithm-Dependency/