It may have to do with the results of is.object(): > is.object(1*structure(1,class="testClass")) [1] FALSE > is.object(structure(1,class="testClass")*1) [1] TRUE > is.object(structure(1,class="testClass")) [1] TRUE
is.object(x) should be true if x has a class attribute, but 1*structute(1,class="testClass") makes a thing with a class attribute but without the 'OBJECT' bit set. Bill Dunlap TIBCO Software Inc - Spotfire Division wdunlap tibco.com > -----Original Message----- > From: r-devel-boun...@r-project.org > [mailto:r-devel-boun...@r-project.org] On Behalf Of Tom Short > Sent: Sunday, April 12, 2009 4:00 PM > To: r-devel@r-project.org > Subject: [Rd] Simple class with an automatic printing issue > > I don't understand the following behavior for a simple S3 class. The > auto-printing at the command line > doesn't behave as I expect. I'm probably missing something, > but it might be > a bug. > > > print.testClass <- function(x, ...) cat("Class:", class(x), > ":", x, "\n") > > > structure(1, class = "testClass") > Class: testClass : 1 > > > print(1 * structure(1, class = "testClass")) > Class: testClass : 1 > > > 1 * structure(1, class = "testClass") # why doesn't > auto-printing call > print.testClass here? > [1] 1 > attr(,"class") > [1] "testClass" > > > structure(1, class = "testClass") * 1 > Class: testClass : 1 > > > platform i386-pc-mingw32 > arch i386 > os mingw32 > system i386, mingw32 > status RC > major 2 > minor 9.0 > year 2009 > month 04 > day 10 > svn rev 48318 > language R > version.string R version 2.9.0 RC (2009-04-10 r48318) > > [[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
