Right, these warnings correctly go away with the changes currently in 
r-devel.

As I said in my mail, I do want to port them to 2.9.1 and was waiting 
for a little more testing.

(Also, I'm about to move back to the East Coast for the summer, and will 
be out of touch for a few days next week.  Seemed a bit nervy to make a 
change to the patched version just before disappearing, but if there's a 
strong argument I could.)

John


Roger Bivand wrote:
> In released 2.9.0, we have been seeing warnings when installing sp, for
> example:
>
> Warning in .checkS3forClass(ClassDef@className, where, names(exts)) :
>   Some of the superclasses in the definition of class "SpatialPoints" have
> apparent S3 methods.
>
> DANGER: the new class will not inherit these methods.
> Complain to the author of the superclass definitions.
>
> The apparent methods are  "plot.Spatial", "summary.Spatial"
>
> Running R CMD check sp (or installing from CRAN) on 2.10.0 (2009-04-29
> r48433) does not generate any such warnings. For us, it would be helpful if
> the extensions could be patched into 2.9.1 (although no user has complained,
> curiously enough).
>
> Roger
>
>
>
> John Chambers-2 wrote:
>   
>> Changes were committed today to the r-devel version of R to make S4 and 
>> S3 classes (and abnormal object types such as "environment") work 
>> together more consistently.
>>
>> Basically, S4 classes can now contain any S3 class or object type, and 
>> should now inherit S3 methods for these.  Also, the main practical 
>> problem with defining S3 methods for other S4 classes (namely, that S4 
>> inheritance was not recognized) has been fixed, to the extent possible.
>>
>> See ?Methods (especially the section on S3 methods).  For details (there 
>> are quite a few) see the paper referenced there,
>>   http://stat.stanford.edu/~jmc4/classInheritance.pdf
>>
>> Since these changes arguably fix design flaws, I would like to see them 
>> in 2.9.1, so please test them out.  For the moment, they are only in the 
>> r-devel version.
>>
>> There can be changes to current behavior.  For example, I found one 
>> regression test for S4 methods that only worked because an apparent S3 
>> method, sort.list, was NOT inherited by an S4 class that contained "list".
>>
>> John
>>
>> ______________________________________________
>> R-devel@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>>
>>     
>
>   

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