[Rd] Changes to methods package

[John Chambers]

A number of changes were committed today.

Mainly:

1.  It should now be possible to install packages using classes and
methods in a more straightforward way, and with or without saved images
(saved images are still recommended for efficiency).  The idea is to be
able to write class & method definitions in a package source, with
default `where' argument, as per examples in the green book.  If another
package is required, call require() in the main source (no longer needed
to call it again in .First.lib).

2.  The second batch of changes to classes & generic functions promised
before, this time mainly to generic functions.  Goals of the changes are
to make class & generic function objects more usable and to make the
methods code work with namespaces.

3.  A change to require() and related functions needed for 1., with the
added feature that detach() now warns if a packages is detached that is
required by another package in the search list.  Another feature needed
for 1. is that the use of sys.source() in library() now sets an option
to the toplevel environment used.  A change to topenv() optionally
allows functions to find this environment (and so make code work the
same with or without saved images).

As far as I know, the changes make things work that didn't before,
rather than the opposite, but there are quite a few changes, so let me
know if otherwise.

Regards,
 John

 
-- 
John M. Chambers                  jmc at bell-labs.com
Bell Labs, Lucent Technologies    office: (908)582-2681
700 Mountain Avenue, Room 2C-282  fax:    (908)582-3340
Murray Hill, NJ  07974            web: http://www.cs.bell-labs.com/~jmc