[Rd] (PR#10534 capture.output(), truncated last output without

[maechler at stat.math.ethz.ch]

>>>>> "BDR" == Brian Ripley <ripley at stats.ox.ac.uk>
>>>>>     on Sat, 29 Dec 2007 13:20:14 +0100 (CET) writes:

    BDR> This only happens if 'file' is a text connection, and
    BDR> is the expected behaviour in that case: you cannot
    BDR> capture an incomplete line to a text connection.

    BDR> There seems no reason to break the documented behaviour
    BDR> in other cases to change something that you consider to
    BDR> a bug when file=NULL and the user does not produce
    BDR> complete output.  It would be possible to make use of
    BDR> isIncomplete() to add a final newline only where needed
    BDR> to complete a line.  E.g. use

    BDR>   if(inherits(file, "textConnection") && isIncomplete(file)) cat("\n")

I think that would be quite a nice improvement.
Martin

    BDR> On Sat, 29 Dec 2007, phgrosjean at sciviews.org wrote:

    >> Full_Name: Philippe Grosjean Version: 2.6.1 OS: MacOS X;
    >> Windows XP Submission from: (NULL) (81.243.237.235)
    >> 
    >> 
    >> Last output from capture.output() is truncated if it does
    >> not end with a carriage return:
    >> 
    >>> capture.output(cat("text\n")) # Fine
    >> [1] "text"
    >>> capture.output(cat("text")) # Missing output!
    >> character(0)
    >>> capture.output({cat("text");1+1}) # Only last output is
    >>> affected
    >> [1] "text[1] 2"
    >> 
    >> Proposed patch: add a carriage return before exiting
    >> capture.output():
    >> 
    >> capture.output <- function (..., file = NULL, append =
    >> FALSE) {
    >> 
    >> 
    >> [...]
    >> 
    >> for (item in tmp) if (item$visible) print(item$value) }
    >> cat("\n") ### ADD THIS!  rval }
    >> 
    >> This changes the behavior of capture.output() a little
    >> bit, since it adds "" at the end of regular outputs, but
    >> it solves the problem and it allows to detect if last
    >> output line was ended by \n, or not.
    >> 
    >> Regards,
    >> 
    >> Philippe Grosjean _ platform i386-apple-darwin8.10.1 arch
    >> i386 os darwin8.10.1 system i386, darwin8.10.1 status
    >> major 2 minor 6.1 year 2007 month 11 day 26 svn rev 43537
    >> language R
    >> 
    >> ______________________________________________
    >> R-devel at r-project.org mailing list
    >> https://stat.ethz.ch/mailman/listinfo/r-devel
    >> 

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
    BDR> Professor of Applied Statistics,
    BDR> http://www.stats.ox.ac.uk/~ripley/ University of
    BDR> Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road,
    BDR> +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865
    BDR> 272595

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