;;;;;
(asdf:defsystem #:robot
:description "The Gendl™ Simplified Android Robot example "
...
:depends-on (#-gendl :gendl)
... )
;;;;;;
The scenario is that we ship a pre-built Gendl image which has no asdf or Quicklisp in it (but does, of course, have :gendl included in *features).
Downstream user is then free to load Quicklisp and start pulling in libraries. But if they pull a library (or application, like :robot), which normally should depend-on :gendl, then we don't want it trying to reload the whole gendl system, since it's already built in.
I know this was discussed here briefly around the launch of 3.0.3 but I'm still not completely clear on how it should work. If we don't include ASDF and Quicklisp at all in our pre-built image, then I don't see any way for us to tamper with e.g. asdf's registry search functions. I guess the only way to do that would be to provide a custom function for installing Quicklisp and ASDF -- but we have no guarantee that the user will actually follow our function and not simply try to install Quicklisp according to the instructions at
quicklisp.org.
--