From roger at ysidro.econ.uiuc.edu  Mon Mar 31 06:05:23 2003
From: roger at ysidro.econ.uiuc.edu (Roger Koenker)
Date: Mon Mar 31 13:00:34 2003
Subject: [Rd] setIs?
Message-ID: <Pine.SOL.4.30.0303310454410.27421-100000@ysidro.econ.uiuc.edu>

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


[Rd] setIs?
Roger Koenker