Dunno, really. Some strange things can happen with nonstandard evaluation, like having a function designed to evaluate something in the parent of its caller, but nonetheless sometimes being called from the command line. So things are sometimes defensively coded.
-pd > On 28 Mar 2016, at 00:08 , Mick Jordan <mick.jor...@oracle.com> wrote: > > A related question is why are sys.parent/parent.frame so permissive in their > error checking? E.g: > > > sys.parent(-1) > [1] 0 > > sys.parent(-2) > [1] 0 > > sys.parent(1) > [1] 0 > > sys.parent(2) > [1] 0 > > parent.frame(4) > <environment: R_GlobalEnv> > > -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
