Re: [Rd] slot named C

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Mon 17 Apr 2006 - 14:39:42 GMT

On Mon, 17 Apr 2006, Paul Gilbert wrote:

> Ok, but I'm surprised. I thought partial matching only happened for
> named arguments. I guess I've been lucky.

Here C is named, so what did you mean?

Partial matching happens for all arguments called by name, except for those following ... in the formals.

>
> Paul
>
> Prof Brian Ripley wrote:
>> It's an error in your usage The args of new() are
>>
>>> args(new)
>> function (Class, ...)
>>
>> and what does 'C' match? You need to name your arguments here.
>>
>> On Mon, 17 Apr 2006, Paul Gilbert wrote:
>>
>>> "C" appears to be an illegal name for a slot in an S4 class (example
>>> below).
>>
>> It is rather an example of something which does not work.
>>
>> foo <- new("testobj")
>> foo@C <- 2
>>
>> does, for example.
>>
>>> If this is a known limitation, and not a bug, it would be nice
>>> if it were caught by setClass.
>>>
>>> Paul Gilbert
>>>
>>>> setClass("testobj", representation ( C = "numeric"))
>>> [1] "testobj"
>>>> new("testobj", C= 2)
>>> Error in methodsPackageMetaName("C", name) :
>>> 'The name of the object (e.g,. a class or generic function) to
>>> find in the meta-data' must be a single string (got an object of class
>>> "numeric")
>>>
>>>> setClass("testobj", representation ( C. = "numeric"))
>>> [1] "testobj"
>>>> new("testobj", C.= 2)
>>> An object of class "testobj"
>>> Slot "C.":
>>> [1] 2
>>> ====================================================================================
>>>
>>>
>>> La version franšaise suit le texte anglais.
>>>
>>> ------------------------------------------------------------------------------------
>>>
>>>
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>>>
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>>>
>>
> ====================================================================================
>
> La version franšaise suit le texte anglais.
>
> ------------------------------------------------------------------------------------
>
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>
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-- 
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 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595


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Received on Tue Apr 18 00:42:06 2006

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