(PR#10534 capture.output(), truncated last output without \n

Thank you, Brian.
This only happens if 'file' is a text connection, and is the expected 
behaviour in that case: you cannot capture an incomplete line to a text 
connection.
Well, in ?textConnection, Details section, one can read:
"Closing the connection will output the final line, complete or not."
There seems no reason to break the documented behaviour in other cases 
to change something that you consider to a bug when file=NULL and the 
user does not produce complete output.  It would be possible to make use 
of isIncomplete() to add a final newline only where needed to complete a 
line.  E.g. use

    if(inherits(file, "textConnection") && isIncomplete(file)) cat("\n")
This is fine, except one cannot detect when the last line was complete 
or not in capture.output(). I suggest adding an attribute complete = 
TRUE/FALSE to the result returned by capture.output(), or any other mean 
to return this information.

Best,

Philippe Grosjean
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

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(PR#10534 capture.output(), truncated last output without \n

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