[R] Accessing methods and extending S4 classes of existing packages

Johannes Huesing johannes at huesing.name
Sun Jun 29 20:17:17 CEST 2008


Johannes Huesing <johannes at huesing.name> [Sun, Jun 29, 2008 at 08:13:27AM CEST]:
> Dear all,
> I am trying to understand how to access S4 methods after loading a 
> package, using the online documentation of getMethod and friends.
> 
> This is what I have been trying:
> > library(coin)
> > findMethods("ApproxNullDistribution")
> list()
> Warning message:
> In findMethods("ApproxNullDistribution") :
>   nicht-generische Funktion an findMethods() übergeben
> 
> whereas in the source of coin I can see the lines: 
> 
> setGeneric("ApproxNullDistribution", function(object, ...)
>     standardGeneric("ApproxNullDistribution"))
> 
> It seems that I am not getting what is going on here. Could anybody
> give me a hint?

It seems like the package authors chose not to export the ApproxNullDistribution
generic method from the package, as seen in the NAMESPACE file of the 
package.

Does it mean that if I want to write personal extensions to the package,
the correct approach is to take the whole package and modify it?
-- 
Johannes Hüsing               There is something fascinating about science. 
                              One gets such wholesale returns of conjecture 
mailto:johannes at huesing.name  from such a trifling investment of fact.                
http://derwisch.wikidot.com         (Mark Twain, "Life on the Mississippi")



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