From maechler at stat.math.ethz.ch  Fri Sep 22 10:00:43 2006
From: maechler at stat.math.ethz.ch (Martin Maechler)
Date: Fri, 22 Sep 2006 10:00:43 +0200
Subject: [Rd] Package dependencies and imports
In-Reply-To: <m2ac4tp1kd.fsf@ziti.local>
References: <20060921152216.UGBW24981.tomts40-srv.bellnexxia.net@JohnDesktop8300>
	<17682.46130.408226.90557@stat.math.ethz.ch>
	<m2ac4tp1kd.fsf@ziti.local>
Message-ID: <17683.38955.494963.729620@stat.math.ethz.ch>

>>>>> "Seth" == Seth Falcon <sfalcon at fhcrc.org>
>>>>>     on Thu, 21 Sep 2006 10:33:06 -0700 writes:

    Seth> Martin Maechler <maechler at stat.math.ethz.ch> writes:
    >>  I think you should use the new DESCRIPTION field and say
    >> 'Enhances: rgl'
    >> 
    >> but I haven't checked if this prevents the warning,
    >> though I think it should..

    Seth> But is Rcmdr enhancing rgl or being enhanced by rgl?

    Seth> :-( :-(

I think this distinction is not so easily made on a general level.
I'd say an argument for how you can (should?) think about this
is the following abstraction:

 There are two packages, A and B. 
 A's DESCRIPTION has 'Enhances: B'.
 When B is there, A provides extra features.
 In one sense, this always enhances B ("enhance" in the usual
 English meaning), since B's area of application has been
 enlarged by code in A.

Martin




[Rd] Package dependencies and imports
Martin Maechler