[R] Method dispatch for print() in package its

[Prof Brian Ripley]

Setting S4 methods for print() works correctly, as in your examples.
Your first example does not call print(), so it is not suprising that no 
method dispatch takes place.

You seem to suppose that such a method should be used for top-level 
auto-printing, and it will not be as your example shows.  Auto-printing 
calls show() on S4 objects, and in this case show() is handling the object 
by its default method.

Note that if there is no S4 print method set, print(x) on an S4 object 'x' 
will in fact call show(x).  So had an S4 show() method been set, all three 
examples would have given the same output (via show()).



On Thu, 12 Apr 2007, Albrecht, Dr. Stefan (AZ Private Equity Partner) wrote:

> Dear all,
>
> in the package its the print() method does not seem to correctly work in all circumstances:
>
>
>> selectMethod(print, "its")
> Method Definition:
>
> function (x, ...)
> {
>    print(x at .Data <mailto:x at .Data> , ...)

(sic!)

> }
> <environment: namespace:its>
>
> Signatures:
>        x
> target  "its"
> defined "its"
>
>
>
>> fundPME.lst[[1]]$irr
> An object of class "its"
>                 IRR  HSBC MEEM
> 2005-10-31 0.1926175 0.07802736
> Slot "dates":
> [1] "2005-10-31 Westeuropäische Normalzeit"
>
>
>> fundPME.lst[[1]]$irr at .Data
>                 IRR  HSBC MEEM
> 2005-10-31 0.1926175 0.07802736
>
>
>> print(fundPME.lst[[1]]$irr)
>                 IRR  HSBC MEEM
> 2005-10-31 0.1926175 0.07802736
>
>
> So, is it necessary to define a print.its S3 method, or what should we do?
>
> Many thanks and best regards,
> Stefan
>
> ____________________________________
> Dr. Stefan Albrecht, CFA
> Allianz Private Equity Partners GmbH
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>
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>
>
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-- 
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)
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