R CMD check: checking examples: how to (not) pause execution

I think the more usual way to solve this is to have the user set 
par(ask=TRUE) is they want to be prompted. This gives the user the option of 
being prompted, or not. It makes the example tests work, and simplifies your 
code because you don't need to worry about the prompt mechanism. It also 
potentially helps with multi-language support, etc, etc.

Paul

Lutz Prechelt wrote:

Hello all,

trying to prepare my first package for submission to CRAN I am stumbling 
over the "checking examples" step
of R CMD check.

I have some examples that produce more than one plot.
I currently separate those plot calls by
 readline("Press <Return> for a plot including a density plot")
or some such to have R wait before producing the next plot.

This works OK for end users, but fails miserably during R CMD check, which 
appears to just eat the
next line of the example source file for the input of readline
(which took me quite a while to understand it).

What is the right way to solve this problem?

I can hardly believe that there is none (although the
examples of 'plot' suggest exactly this: They run through multiple plots in 
a hurry.)

I guess the appropriate approach would be if
example() had some kind of single-stepping option?

Any hints?

 Lutz Prechelt

P.S.: Documentation remark:
For users struggling with R CMD check it might be
very helpful if R-exts.pdf contained some pointers
to the functions or mechanisms used by R CMD check, or the names of source 
files where to find such information
so they can better understand what is going on.

Prof. Dr. Lutz Prechelt; prechelt at inf.fu-berlin.de
Institut fuer Informatik; Freie Universitaet Berlin
Takustr. 9; 14195 Berlin; Germany
+49 30 838 75115; http://www.inf.fu-berlin.de/inst/ag-se/