[asdf-devel] Incrementally extending the source registry?

[Zach Beane]

Say I download a tarball that has a number of projects in it:

  $ tar xzvf fooprojects.tgz
  fooprojects/neato/neato.asd
  fooprojects/neato/neato.lisp
  fooprojects/stuff/stuff.asd
  fooprojects/stuff/stuff.lisp
  fooprojects/xyz/xyz.asd
  fooprojects/xyz/xyz.lisp

If these are now unpacked in ~/src/fooprojects/, how can I add that tree
to my ASDF source registry by calling ASDF functions?

Say a few minutes later I download another tarball with a number of
projects in it:

  $ tar xzvf barprojects.tgz
  barprojects/awesome/awesome.asd
  barprojects/awesome/awesome.lisp
  barprojects/stump/stump.asd
  barprojects/stump/stump.lisp
  barprojects/tapper/tapper.asd
  barprojects/tapper/tapper.lisp

If these are now unpacked in ~/src/barprojects/, how can I add that tree
to my ASDF soruce registry by calling ASDF functions, without losing the
previous fooprojects registration?

Thanks,
Zach