Thank you gents, I overlooked the subtle differences. On Tue, Mar 28, 2017 at 2:49 PM, Lukas Stadler <lukas.stad...@oracle.com> wrote:
> “typeof” is your friend here: > > > typeof(`[`) > [1] "special" > > typeof(mc[[1]]) > [1] "symbol" > > typeof(mc2[[1]]) > [1] "special" > > so mc[[1]] is a symbol, and thus not a primitive. > > - Lukas > > > On 28 Mar 2017, at 14:46, Michael Lawrence <lawrence.mich...@gene.com> > wrote: > > > > There is a difference between the symbol and the function (primitive > > or closure) to which it is bound. > > > > This: > > mc2 <- as.call(list(`[`,iris,2,"Species")) > > > > Evaluates `[` to its value, in this case the primitive object, and the > > primitive itself is incorporated into the returned call. > > > > If you were to do this: > > mc2 <- as.call(list(quote(`[`),iris,2,"Species")) > > > > The `[` would _not_ be evaluated, quote() would return the symbol, and > > the symbol would end up in the call. > > > > The two forms have virtually identical behavior as long as the call > > ends up getting evaluated in the same environment. > > > > On Tue, Mar 28, 2017 at 3:03 AM, Joris Meys <jorism...@gmail.com> wrote: > >> Dear, > >> > >> I have noticed this problem while looking at the following question on > >> Stackoverflow : > >> > >> http://stackoverflow.com/questions/42894213/s4-class- > subset-inheritance-with-additional-arguments > >> > >> While going through callNextMethod, I've noticed the following odd > >> behaviour: > >> > >> mc <- call("[",iris,2,"Species") > >> > >> mc[[1]] > >> ## `[` > >> > >> is.primitive(`[`) > >> ## [1] TRUE > >> > >> is.primitive(mc[[1]]) > >> ## [1] FALSE > >> # Expected to be TRUE > >> > >> mc2 <- as.call(list(`[`,iris,2,"Species")) > >> > >> is.primitive(mc2[[1]]) > >> ## [1] TRUE > >> > >> So depending on how I construct the call (using call() or as.call() ), > the > >> function `[` is or is not recognized as a primitive by is.primitive() > >> > >> The behaviour is counterintuitive and -unless I miss something obvious > >> here- likely to be a bug imho. I immediately admit that my C chops > aren't > >> sufficient to come up with a patch. > >> > >> Cheers > >> Joris > >> > >> -- > >> Joris Meys > >> Statistical consultant > >> > >> Ghent University > >> Faculty of Bioscience Engineering > >> Department of Mathematical Modelling, Statistics and Bio-Informatics > >> > >> tel : +32 (0)9 264 61 79 > >> joris.m...@ugent.be > >> ------------------------------- > >> Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php > >> > >> [[alternative HTML version deleted]] > >> > >> ______________________________________________ > >> R-devel@r-project.org mailing list > >> https://stat.ethz.ch/mailman/listinfo/r-devel > > > > ______________________________________________ > > R-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel > > -- Joris Meys Statistical consultant Ghent University Faculty of Bioscience Engineering Department of Mathematical Modelling, Statistics and Bio-Informatics tel : +32 (0)9 264 61 79 joris.m...@ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
