[Rd] Caching bug with showMethods?

Seth Falcon sfalcon at fhcrc.org
Wed Oct 18 16:30:12 CEST 2006

John Chambers <jmc at r-project.org> writes:
> No, not a bug.
> Inherited methods are never cached until they are needed, for rather
> obvious efficiency reasons. See ?showMethods, under argument
> inherited=

ok, I missed the doc, which is quite clear about showMethods not doing
what I wanted...

> If what you were trying to do was find out what method would be called
> for class "B" without calling it, use selectMethod().

Yes, that is what I was trying to do.  I thought showMethods was the
preferred user interface to ask the system about what methods are

When would one want the behavior of showMethods?  Is it ever useful
for a user to ask, "what are the methods that have been cached?".

The problem with using selectMethod is one needs to know in advance
the name of a generic.  I would like to have a tool that lets me
discover "what can be done" with an instance of a given class.
showMethods is very close to being that tool, but the interaction with
the method caching makes it confusing (until one has a solid
understanding of the method caching, but IMHO this isn't something a
user should need to know about if at all possible).


+ seth

Seth Falcon | Computational Biology | Fred Hutchinson Cancer Research Center

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