extract-documentation (packages directory &rest keys &key include-slot-definitions-p &allow-other-keys)

packages -- List of package designators. Documentation will be generated for these packages.
directory -- A pathname specifying a directory. The output file will be written to this directory, which must already exist.
include-slot-definitions-p -- A boolean.
keys -- Extra parameters for stylesheets.

Extracts docstrings from packages and writes them in XML syntax to the file .atdoc.xml in the specified directory.

With include-slot-definitions-p, class documentation will include a list of direct slots.

Extra parameters will be inserted as attributes on the root element.