From maechler at stat.math.ethz.ch  Tue May 22 19:41:34 2007
From: maechler at stat.math.ethz.ch (Martin Maechler)
Date: Tue, 22 May 2007 19:41:34 +0200
Subject: [Rd] relist, an inverse operator to unlist
In-Reply-To: <20070522115154.GS28199@econ.upenn.edu>
References: <20070513172911.GP6923@econ.upenn.edu>
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	<20070514043240.GL28199@econ.upenn.edu>
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	<17992.5499.383704.358418@stat.math.ethz.ch>
	<20070519153636.GJ21178@econ.upenn.edu>
	<20070519160413.GK21178@econ.upenn.edu> <m2r6p990j5.fsf@ziti.local>
	<20070522115154.GS28199@econ.upenn.edu>
Message-ID: <18003.11086.212085.683279@stat.math.ethz.ch>

>>>>> "AndrewC" == Andrew Clausen <clausen at econ.upenn.edu>
>>>>>     on Tue, 22 May 2007 07:51:54 -0400 writes:

    AndrewC> Hi Seth,
    AndrewC> 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")))

    AndrewC> That's an excellent suggestion.  Thanks!  However, I had to set the signature
    AndrewC> to c("numeric", "missing") rather than just "numeric".

    AndrewC> I have uploaded a new version here:

    AndrewC> http://www.econ.upenn.edu/~clausen/computing/relist.R

This looks "good from far".

I won't have time to do anything more about it for the next few
days.
Please remind me (in private) about it if you don't hear back
within one week.

Martin

    AndrewC> Cheers,
    AndrewC> Andrew



[Rd] relist, an inverse operator to unlist
Martin Maechler