>>>>> Michael Lawrence <lawrence.mich...@gene.com>
>>>>> on Mon, 26 Jan 2015 06:11:50 -0800 writes:
> isLoadedNamespace() sounds fine to me..
> Thanks for addressing this,
> Michael
Ok, this is now in R-devel :
------------------------------------------------------------------------
r67624 | maechler | 2015-01-26 18:26:00 +0100 (Mon, 26 Jan 2015) | 1 line
Changed paths:
M doc/NEWS.Rd
M src/library/base/R/attach.R
M src/library/base/R/library.R
M src/library/base/R/namespace.R
M src/library/base/man/ns-load.Rd
M src/library/methods/R/RMethodUtils.R
M src/library/methods/R/refClass.R
M src/library/tools/R/QC.R
M src/library/tools/R/install.R
M src/library/utils/R/indices.R
M src/main/envir.c
M src/main/names.c
new function isLoadedNamespace(name) and use wherever "obvious" in our code
------------------------------------------------------------------------
> On Mon, Jan 26, 2015 at 5:51 AM, Martin Maechler <
> maech...@lynne.stat.math.ethz.ch> wrote:
>> >>>>> Michael Lawrence <lawrence.mich...@gene.com>
>> >>>>> on Mon, 26 Jan 2015 05:12:55 -0800 writes:
>>
>> > A isNamespaceLoaded() function would be a useful thing to
>> > have in general if we are interested in readable code. An
>> > efficient implementation would be just a bonus.
>>
>> Good point (readability), and thank you for the support!
>>
>> Note one slight drawback with your name (which is clearly
>> better than mine first proposal):
>> We'd have the three functions named
>>
>> isBaseNamespace(ns)
>> isNamespace(ns)
>> isNamespaceLoaded(name)
>>
>> where 'name' is really different from 'ns', namely :
>>
>> > isNamespace("stats")
>> [1] FALSE
>> > isNamespace(asNamespace("stats"))
>> [1] TRUE
>>
>> but
>>
>> > isNamespaceLoaded("stats")
>> [1] TRUE
>>
>> > isNamespaceLoaded(asNamespace("stats"))
>> Error in as.vector(x, "symbol") :
>> cannot coerce type 'environment' to vector of type 'symbol'
>> >
>>
>> So, from my (non native English view) a slightly more suggestive
>> function name may be
>>
>> isLoadedNamespace(name)
>>
>> or using Luke's original language, still present in the C code,
>>
>> isRegisteredNamespace(name)
>>
>> but I would prefer the former, isLoadedN..S..()
>>
>> Martin
>>
>> > On Mon, Jan 26, 2015 at 3:36 AM, Martin Maechler
>> > <maech...@lynne.stat.math.ethz.ch> wrote:
>> >>>>>>> Winston Chang <winstoncha...@gmail.com> on Fri, 23
>> >>>>>>> Jan 2015 10:15:53 -0600 writes:
.............................
.............................
>> >> Hence, indeed, !is.null(.getNamespace(pkg))
>> >>
>> >> seems equivalent to pkg %in% loadedNamespaces()
>> >>
>> >> --- when 'pkg' is of length 1 (!!!)
>> >>
>> >> but is 20 times faster.... and we have 11 occurrences of
>> >> ' <...> %in% loadedNamespaces() ' in the "base packages"
>> >> in the R (devel) sources, 3 in base, 2 in methods, 3 in
>> >> stats, 2 in tools, 1 in utils..
>> >>
>> >> On the other hand, pkg %in% loadedNamespaces()
>> >>
>> >> is extremely nicely readable code, whereas
>> >> !is.null(.getNamespace(pkg)) is pretty much the contrary.
>> >> .. and well readable code is so much easier to maintain
>> >> etc, such that in many cases, code optimization with the
>> >> cost of code obfuscation is *not* desirable.
>> >>
>> >> Of course we could yet again use a few lines of C and R
>> >> code to provide a new R lowlevel function, say
>> >>
>> >> is.loadedNamespace()
>> >>
>> >> which would be even faster than
>> >> !is.null(.getNamespace(pkg))
>> >>
>> >> ... ...
>> >>
>> >> but do we have *any* evidence that this would noticably
>> >> speedup any higher level function such as library() ?
>> >>
>> >>
>> >> Thank you, again, Winston; you've opened an interesting
>> >> topic!
>> >>
>> >> --
>> >> Martin Maechler, ETH Zurich
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