bug and fix : using panel.first with plot() in do.call() (PR#457)
On Fri, 25 Feb 2000 c.farrow@compserv.gla.ac.uk wrote:
The following works as expected
plot(1:5, panel.first=grid(2,2))
and if
my.panel<-function() grid(2,2)
then
plot(1:5, panel.first=my.panel() )
is also OK
but,
do.call("plot", list(x=1:5, panel.first=grid(2,2))
do.call("plot", list(x=1:5, panel.first=my.panel))
do.plot("plot", list(x=1:5, panel.first=my.panel() ))
do not draw the grid because the panel.first expression is evaluated
before the plot gets drawn.
Yes, and a solution is
do.call("plot", list(x=1:5, panel.first=quote(grid(2,2))))
as when you do this sort of thing you can't rely on lazy evaluation.
replacing `quote' by `delay' will also work. The help page says
they should be unevaluated expressions.
A solution is to modify plot.default such that the line
panel.first
is replaced by
if(is.function(panel.first)) {
panel.first()
}else {
panel.first
}
This allows the previous behaviour, but also allows a function name to
be passed to plot using do.call()
now all the following produce the expected graph
plot(1:5, panel.first=grid(2,2))
plot(1:5, panel.first=my.panel())
plot(1:5,panel.first=my.panel)
do.call("plot", list(x=1:5, panel.first=my.panel ))
Similarly the line
panel.last
should be replaced by
if(is.function(panel.last)) {
panel.last()
} else {
panel.last
}
Um, ?plot.default say panel.first and panel.last should be *expressions* *to be evaluated*, so is this not working as documented?
Brian D. Ripley, ripley@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._