[Rd] Spurious output white line in R script (PR#8631)
Prof Brian Ripley
ripley at stats.ox.ac.uk
Thu Feb 23 17:53:19 CET 2006
On Thu, 23 Feb 2006, Thomas Lumley wrote:
> On Thu, 23 Feb 2006, Prof Brian Ripley wrote:
>> On Wed, 22 Feb 2006, François Pinard wrote:
>>> So, I was not expecting R, running with that option activated, to
>>> "volunteer" white lines. :-)
>> But Simon said `with the documentation'. Not doing what you expected is
>> not a bug. Can you please point us to documentation which says that
>> end-of-file produces no output?
>> This does appear to be deliberate behaviour from
>> void end_Rmainloop(void)
>> /* run the .Last function. If it gives an error, will drop back to main
>> loop. */
>> R_CleanUp(SA_DEFAULT, 0, 1);
>> and I think it is necessary, as R might well have a partial line of output
>> queued up for the console. So this is probably `as quietly as possible'.
> (While agreeing entirely on the "bug" issue), couldn't we have fflush()
> instead of sending a newline?
Well, we might not be outputting to a file ... (I did say console), and
.Last() might well produce output so we need to leave the console in a
suitable state. I do think we need a \n unless we can be sure that we are
currently at the left margin of the console (and I am not sure we can be
unless we assume all output went through R[E]printf, and even in that
case we do not currently collect the information).
Consider the script
gannet% cat foo
R --slave --vanilla <<EOF
.Last <- function() cat("goodbye\n")
We do not want
or at least, I do not want that.
Beyond that, there must be hundreds or more reference results of test runs
against which comparisons are made, and this might well affect a lot of
testing code, although perhaps we could conditionalize on --slave.
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
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