>>>>> 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 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel