[Rd] relist, an inverse operator to unlist

Seth Falcon sfalcon at fhcrc.org
Wed May 23 14:45:41 CEST 2007

Andrew Clausen <clausen at econ.upenn.edu> writes:

> Hi Seth,
> On Mon, May 21, 2007 at 05:15:10PM -0700, Seth Falcon wrote:
>> I will also add that the notion of a default argument on a generic
>> function seems a bit odd to me.  If an argument is available for
>> dispatch, I just don't see what sense it makes to have a default.  In
>> those cases, the default should be handled by the method that has a
>> signature with said argument matching the "missing" class.
>> What often does make sense is to define a generic function where some
>> argument are not available for dispatch.  For example:
>> setGeneric("foo", signature="flesh",
>>            function(flesh, skeleton=attr(flesh, "skeleton") 
>>                standardGeneric("foo")))
> That's an excellent suggestion.  Thanks!  However, I had to set the signature
> to c("numeric", "missing") rather than just "numeric".
> I have uploaded a new version here:
> 	http://www.econ.upenn.edu/~clausen/computing/relist.R

I misunderstood.  You aren't using S4 classes/methods at all
and so I don't actually see how my comments could have been helpful in
any way.  relist seems like a really odd solution to me, but based on
the discussion I guess it has its use cases.


+ seth

Seth Falcon | Computational Biology | Fred Hutchinson Cancer Research Center

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