taxy

This library provides a programmable way to classify arbitrary
objects into a hierarchical taxonomy.  (That's a lot of fancy words
to say that this lets you put things in nested groups.)

Helpful features include:

+ Dynamic taxonomies: Objects may be classified into hierarchies
automatically defined at runtime based on their attributes.

+ Reusable taxonomies: Taxonomy definitions may be stored in
variables and reused in other taxonomies' descendant groups.

Basic usage:

1.  Make a taxy with `make-taxy'.
2.  Fill the taxy with items using `taxy-fill'.
3.  For a simple display of a taxy's items, use `taxy-plain'.

For more details, please see the README.org file.