R devel - Sep 2006 - example(..., ask=getOption("example.ask"))

Hi,

I wish to return to the topic "[Rd] example(ask = .) - default ?"
discussed in R-devel on May 1, 2006, because I think it is related to
my problem.

In one of my Rd examples I generate multiple (20-30!) PNG files using
png()/dev.off().  I noticed that I get a "Hit <Return> to see next
plot:" for each png() call, when calling example() [interactively].

The code for example() has:

    if (ask == "default")
        ask <- echo && dev.interactive(orNone = TRUE)
    if (ask) {
        if (.Device != "null device") {
            opar <- par(ask = TRUE)
            on.exit(par(opar))
        }
        op <- options(par.ask.default = TRUE)
        on.exit(options(op), add = TRUE)
    }

When calling example() interactively, either with ask=TRUE (explicitly
or indirectly with getOption("example.ask") == "default"),
option
'par.ask.default' is set to TRUE.  This seems to be the reason for the
above.  Example:
> options(par.ask.default=TRUE)
> png("foo.png"); plot(1); dev.off()
Hit <Return> to see next plot:
null device
          1
> options(par.ask.default=FALSE)
> png("foo.png"); plot(1); dev.off()
null device
          1

Best

Henrik

And your point/question is?

par(ask = TRUE) applies to all devices, including png.  Try setting
options(par.ask.default = FALSE in your example?


On Wed, 13 Sep 2006, Henrik Bengtsson wrote:
> Hi,
> 
> I wish to return to the topic "[Rd] example(ask = .) - default ?"
> discussed in R-devel on May 1, 2006, because I think it is related to
> my problem.
> 
> In one of my Rd examples I generate multiple (20-30!) PNG files using
> png()/dev.off().  I noticed that I get a "Hit <Return> to see
next
> plot:" for each png() call, when calling example() [interactively].
> 
> The code for example() has:
> 
>     if (ask == "default")
>         ask <- echo && dev.interactive(orNone = TRUE)
>     if (ask) {
>         if (.Device != "null device") {
>             opar <- par(ask = TRUE)
>             on.exit(par(opar))
>         }
>         op <- options(par.ask.default = TRUE)
>         on.exit(options(op), add = TRUE)
>     }
> 
> When calling example() interactively, either with ask=TRUE (explicitly
> or indirectly with getOption("example.ask") ==
"default"), option
> 'par.ask.default' is set to TRUE.  This seems to be the reason for
the
> above.  Example:
> 
> > options(par.ask.default=TRUE)
> > png("foo.png"); plot(1); dev.off()
> Hit <Return> to see next plot:
> null device
>           1
> > options(par.ask.default=FALSE)
> > png("foo.png"); plot(1); dev.off()
> null device
>           1
> 
> Best
> 
> Henrik
> 
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
> 
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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