Re: [Rd] inherits() and virtual classes

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Wed, 27 Jun 2007 08:40:57 +0100 (BST)

inherits() is not to do with S4 classes: it tests inheritance in the base class system.

See ?is in package 'methods'.

> is(jj, "onion")

[1] TRUE On Wed, 27 Jun 2007, Robin Hankin wrote:

> Hi
>
> How do I test for an object having a particular virtual class?
>
> In the following, "onion" is a virtual class, and "octonion" is
> a non-virtual class contained in onion. The last call
> to inherits() gives FALSE [R-2.5.0], when inherits.Rd led
> me to expect TRUE.
>
>
>
>
> setClass("onion",
> representation = "VIRTUAL"
> )
>
> setClass("octonion",
> representation = representation(x="matrix"),
> prototype = list(x=matrix(numeric(),0,8)),
> contains = "onion"
> )
>
>
> jj <- new("octonion",x=as.matrix(1:8))
>
> inherits(jj,"onion")
>
>
>
>
> --
> Robin Hankin
> Uncertainty Analyst
> National Oceanography Centre, Southampton
> European Way, Southampton SO14 3ZH, UK
> tel 023-8059-7743
>
> ______________________________________________
> R-devel_at_r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>

-- 
Brian D. Ripley,                  ripley_at_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 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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