[R] Suppressing certain debugging output

[Prof Brian Ripley]

On Mon, 21 Dec 2009, Stuart Andrews wrote:

> keywords: debug, do.call, "debugging in", suppress, arguments, list, screen, 
> console, output
>
> Hi,
>
> I would like to control the output to the console while debugging functions 
> that are called by do.call( FCN, ARGUMENTS )  when the arguments are quite 
> large.  Is there a simple way to suppress (or compress) this output?

Yes.  From ?options

      ‘deparse.max.lines’: controls the number of lines used when
           deparsing in ‘traceback’, ‘browser’, and upon entry to a
           function whose debugging flag is set.  Initially unset, and
           only used if set to a positive integer.

>
> Thanks,
> - Stu
>
>
> For example:
>
> ttt = function(x) { length(x) };  debug(ttt);  do.call(ttt, 
> list(x=rep(0,10)))
> ttt = function(x) { length(x) };  debug(ttt);  do.call(ttt, 
> list(x=rep(0,100)))
> ttt = function(x) { length(x) };  debug(ttt);  do.call(ttt, 
> list(x=rep(0,10000000)))
>
>
> The first line prints the following to the console ...
>
> debugging in: function(x) { length(x) }
> (x = c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0))
> debug: {
>   length(x)
> }
> Browse[1]>
>
>
> The second prints ...
>
> debugging in: function(x) { length(x) }
> (x = c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0))
> debug: {
>   length(x)
> }
> Browse[1]>
>
>
> Etc.
> Etc.
>
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-- 
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)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595