R devel - Mar 2003 - setIs?

I've recently updated from an early February version of 1.7.0 to

Version 1.7.0 Under development (unstable) (2003-03-25)

and am now having problems with errors giving the message:

  ' getExtends(ClassDef) : @ must be used on an object with a formal
class'

which seems to be caused by 'setIs("character","character or
NULL")'
which attempts to define 'character' as an extension of the virtual
class 'character or NULL' defined in 'setClass("character or
NULL")'.
If I try this:
> library(methods)
> setClass("CN")
[1] "CN"
> setIs("NULL","CN")
> setIs("numeric","CN")
> setIs("character","CN")
Error in getExtends(ClassDef) : @ must be used on an object with a formal class

The fact that 'setIs("numeric","CN")' and
'setIs("NULL","CN")' work just fine
leads me to believe that this is a bug in the new R-devel version.

url:	www.econ.uiuc.edu	Roger Koenker		Dept. of Economics UCL,
email	rkoenker@uiuc.edu	Department of Economics Drayton House,
vox: 	217-333-4558		University of Illinois	30 Gorden St,
fax:   	217-244-6678		Champaign, IL 61820	London,WC1H 0AX, UK

That's not the current version you are using, and it does work in the
current version.

However, that was caused by an additional consistency check, so I believe
it revealed a bug in the older version that we have not yet tracked down
(but have turned the check off).


On Mon, 31 Mar 2003, Roger Koenker wrote:
> I've recently updated from an early February version of 1.7.0 to
>
> Version 1.7.0 Under development (unstable) (2003-03-25)
>
> and am now having problems with errors giving the message:
>
>   ' getExtends(ClassDef) : @ must be used on an object with a formal
class'
>
> which seems to be caused by
'setIs("character","character or NULL")'
> which attempts to define 'character' as an extension of the virtual
> class 'character or NULL' defined in 'setClass("character
or NULL")'.
> If I try this:
>
> > library(methods)
> > setClass("CN")
> [1] "CN"
> > setIs("NULL","CN")
> > setIs("numeric","CN")
> > setIs("character","CN")
> Error in getExtends(ClassDef) : @ must be used on an object with a formal
class
>
> The fact that 'setIs("numeric","CN")' and
'setIs("NULL","CN")' work just fine
> leads me to believe that this is a bug in the new R-devel version.
-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595