[Rd] Unexpected behavior with \r in Rgui 2.12.0

[Prof Brian Ripley]

First, I don't think  cat(70,"\r")  has ever been useful in Rgui.
It outputs and then deletes a line: Rgui has never supported 
overwriting.  I think you really want cat('\r', i, sep="").

Second, in some circumstances in 2.12.0 only, some storage was 
discarded too early and so random characters might appear.  This has 
now been fixed, so please try a recent R-patched.

But the main problem was the expectation: there is nothing that I know 
of which says that '\r' works in the way it does in some (but not all) 
Unix terminals.

On Sun, 7 Nov 2010, Russell Pierce wrote:

> I am experiencing unexpected behavior with the command cat under
> Window GUI builds of R version 2.12.0 (it does not seem to be an issue
> in Rterm).  For example if I issue the command cat(70,"\r") I get back
> text that looks like Asian characters.  If I highlight and copy that
> text, it is the text I would regularly expect, e.g. the number 70 and
> the prompt line.  Highlighting the text changes what is shown on the
> screen, but the screen never displays the number 70.  This error is
> not idiosyncratic to 70 but happens with a fairly wide range of
> numbers.  Notably no error like this occurs when I use \n.  I use \r
> for large simulation runs when I don't want my progress to spam the
> display.
>
> e.g.
> for (i in 1:1000) {cat(i,"\r");flush.console();Sys.sleep(.100)}
>
> sessionInfo() where I first saw the problem:
> R version 2.12.0 (2010-10-15) on Windows Vista
> Platform: i386-pc-mingw32/i386 (32-bit)
>
> locale:
> [1] LC_COLLATE=English_United States.1252
> [2] LC_CTYPE=English_United States.1252
> [3] LC_MONETARY=English_United States.1252
> [4] LC_NUMERIC=C
> [5] LC_TIME=English_United States.1252
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> Also experienced here:
> R version 2.12.0 (2010-10-15) on Windows XP
> R version 2.12.0 Patched (2010-11-04 r53530) on Windows Vista
> R version 2.13.0 Under development (unstable) (2010-11-04 r53530) on
> Windows Vista
>
> But not here:
> Not under R version 2.10.1 (2009-12-14) on Windows XP
>
> If this is expected behavior would you please kindly explain it to me?
> I am not a member of this list, so please address replies both to my
> email address and (if appropriate) the list.
>
> Best,
>
> Russell Pierce
>
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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