Hi everyone,

I'd like to run a little poll among experienced Lisp developers. The topic is the usage in the wild of the extensions to the package system provided by various implementations. My apologies to people who are subscribed to the ABCL mailing list, where some time ago I submitted the same questions getting back several insightful answers but no actual data.

So, here is how it is. I'm working on a novel idea (I hope) regarding symbols and packages; I won't go into the details now. It suffices to say that there is some overlap with features offered by certain Lisp implementations, namely:

 * package-local nicknames: the ability to specify, for each package, a list of nicknames for other packages which are in effect only in that package; available on ABCL and SBCL (http://www.sbcl.org/manual/#Package_002dLocal-Nicknames) and possibly other implementations I'm not aware of.
 * "Hierarchical" packages: a naming convention for packages understood by the reader and a few support functions, which allow to have concise nicknames for a group of closely related packages, such as com.foo.mylib.api and com.foo.mylib.implementation. Found natively in Allegro CL (http://franz.com/support/documentation/current/doc/packages.htm) and in an open-source library by P. Bourguignon.

My questions:
1) First and foremost, is anybody actually using those features? What are you using them for?
2) If yes, how useful are they for you? What shortcomings do you find in them?