On Mon, Feb 27, 2012 at 9:19 AM, Martin Maechler
<maech...@stat.math.ethz.ch> wrote:
>>>>>> Jeffrey Ryan <jeffrey.r...@lemnica.com>
>>>>>> on Mon, 27 Feb 2012 07:39:32 -0600 writes:
>
> > Doesn't this also mean that if Matrix is loaded first,
> > det() will be calling Matrix::determinant, which could be
> > quite surprising change in behavior from expectation?
>
>
> > This seems rather dangerous and 'untrustworthy' to me -
> > unless I am missing some other hidden mechanism involved here.
>
> The only change in R-devel is that library() does not warn about
> *conflicts* in such a case.
Yes, I understand that is only the warning here - but what, aside from
hiding a conflict (which the user may *indeed* care about), does this
accomplish?
To me, a conflict is something to be aware of - hiding it is where I
become concerned.
Without warning, one R script may run differently now depending on
packages loaded, and not just package functions explicitly called by
the script. Without the warning I can envision countless hours
attempting to debug errors - if one is lucky enough to note the change
in behavior.
Behavioral changes can also related to performance. I had seen this
previously with some cbind behavior when the S4 variant from
package:methods overwrote the (much faster) base::cbind by a package
which I will not name (and has since been fixed).
Jeff
> This behavior (and the R code in library()'s checkConflicts())
> is completely analogous to
> importFrom("base", det)
> export(det)
> but as you surely know, we can not (yet?) import from base.
>
> So again: No changed behavior of R, just some warnings less in a
> case where they are typically inappropriate.
>
> > I haven't read the code yet, and I am sure Matrix will "do
> > the right thing", but I have strong reservations about
> > this behavior when applied to the general universe of R
> > and CRAN.
>
> > Jeff
>
> > On Mon, Feb 27, 2012 at 6:03 AM, Martin Maechler
> > <maech...@stat.math.ethz.ch> wrote:
> >>>>>>> Matthew Dowle <mdo...@mdowle.plus.com> on Mon,
> >>>>>>> 27 Feb 2012 09:59:43 +0000 writes:
> >>
> >> > Hello,
> >>
> >> > Regarding this in R-devel/NEWS/New features :
> >>
> >> > o 'library(pkg)' no longer warns about a conflict
> >> with a > function from 'package:base' if the function
> >> is an > identical copy of the base one but with a
> >> different > environment.
> >>
> >> > Why would one want an identical copy in a different
> >> > environment? I'm thinking I may be missing out on a
> >> trick > here.
> >>
> >> Yes, you are ;-) The trick is called ``namespace'' :
> >>
> >> One example which lead me to implement the above:
> >>
> >> The Matrix package has had an identical copy of 'det' for
> >> a while now, but of course in the Matrix namespace.
> >> Because of that, the call to determinant() inside det()
> >> will correctly dispatch Matrix methods for determinant(),
> >> whereas base::det() would not.
> >>
> >> Martin
> >>
> >> ______________________________________________
> >> R-devel@r-project.org mailing list
> >> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>
>
> > --
> > Jeffrey Ryan jeffrey.r...@lemnica.com
>
> > www.lemnica.com www.esotericR.com
>
> > R/Finance 2012: Applied Finance with R www.RinFinance.com
>
> > See you in Chicago!!!!
>
> ______________________________________________
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
--
Jeffrey Ryan
jeffrey.r...@lemnica.com
www.lemnica.com
www.esotericR.com
R/Finance 2012: Applied Finance with R
www.RinFinance.com
See you in Chicago!!!!
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