[R] repeat { readline() }

[Prof Brian Ripley]

On Sun, 8 Jan 2006, Prof Brian Ripley wrote:

> Ctrl-Break works: see the rw-FAQ and README.rterm.  (You'll need a return
> to see a new prompt.)
>
> It is related to your reading directly from the console, so Ctrl-C is
> getting sent to the wrong place, I believe.  (There's a comment from Guido
> somewhere in the sources about this, and this seems corroborated by the
> fact that Ctrl-C will interrupt under Rterm --ess.)

Although the comment is there (in psignal.c), on closer examination the 
cause is a change Guido made to getline.c, so Ctrl-C is treated as a 
character during keyboard input.  I doubt if that was intentional (0 is 
not the default state) and I have changed it for R-devel.\

>
> On Sun, 8 Jan 2006, Henrik Bengtsson wrote:
>
>> Hi.
>>
>> Using Rterm v2.2.1 on WinXP, is there a way to interrupt a call like
>>
>>  repeat { readline() }
>>
>> without killing the Command window?  Ctrl+C is not interrupting the loop:
>>
>> R : Copyright 2006, The R Foundation for Statistical Computing
>> Version 2.2.1 Patched (2006-01-01 r36947)
>> <snip></snip>
>>
>>> repeat { readline() }
>> ^C
>> ^C
>> ^C
>> ^C
>>
>> On Unix it works.  The problem seems to get the interrupt signal to
>> "occur" outside the readline() call so that "repeat" is interrupted. Doing
>>
>> repeat { readline(); Sys.sleep(3) }
>>
>> and it is likely that can generate an interrupt signal outside readline().
>>
>> It seem like readline()/readLines(n=1) or an underlying method catches
>> the interrupt signal quietly and just waits for a symbol to come
>> through.  Try readline() by itself and press Ctrl+C.  Maybe this is a
>> property of the Windows Command terminal, I don't know, but is it a
>> wanted feature and are R core aware of it?  Note that, in Rgui it is
>> possible to interrupting such a loop by pressing ESC.
>>
>> Cheers
>>
>> Henrik
>>
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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
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>

-- 
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