[Rd] how to properly extend s3 data.frames with s4 classes?

[Tim Bergsma]

Dear Ulf Martin,

Thank you for your thoughtful analysis regarding the use of S3 data 
frames in S4.  I asked the same question (in a more rudimentary manner) 
on the r-help list on 30 Nov 2006 and 04 Dec 2006.  There were no 
replies.  If you find a solution, please post.

Best Regards,

Tim Bergsma, PhD

Date: Wed, 24 Jan 2007 12:28:46 +0100
From: Ulf Martin <ulfmartin at web.de>
Subject: [Rd] how to properly extend s3 data.frames with s4 classes?
To: R-devel mailing list <r-devel at r-project.org>
Message-ID: <45B742EE.4050905 at web.de>
Content-Type: text/plain; charset=ISO-8859-15; format=flowed

Dear R Programmers!

After some time of using R I decided to work through John Chambers book
"Programming with Data" to learn what these S4 classes are all about and
how they work in R. (I regret not having picked up this rather fine book
earlier!)

I know from the documentation and the mailing archives that S4 in R is
not 100% the book and that there are issues especially with dataframes,
but to my knowledge the following has not been reported yet.


Summary...