>>>>> 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.
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!!!!
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