Line numbers with errors and warnings?
Gentleman, This thread has been of great interest. Perhaps I missed part of it, but do far I have not seen an example of code that has line numbers that demonstrates how one can (in some instances) recover the line number of an error. Can I impose upon the people who contributed to this thread to post example code? The question if very important, and the discussion about solutions has been somewhat abstract to this point. Thank you, John John David Sorkin M.D., Ph.D. Chief, Biostatistics and Informatics University of Maryland School of Medicine Division of Gerontology Baltimore VA Medical Center 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 (Phone) 410-605-7119 (Fax) 410-605-7913 (Please call phone number above prior to faxing)>>> Milan Bouchet-Valat <nalimilan at club.fr> 12/2/2012 4:00 PM >>> Le dimanche 02 d?cembre 2012 ? 14:21 -0500, Duncan Murdoch a ?crit :
On 12-12-02 9:52 AM, Milan Bouchet-Valat wrote:
Le dimanche 02 d?cembre 2012 ? 09:02 -0500, Duncan Murdoch a ?crit
:
On 12-12-02 8:33 AM, Milan Bouchet-Valat wrote:
Le dimanche 02 d?cembre 2012 ? 06:02 -0500, Steve Lianoglou a
?crit :
Hi, On Sun, Dec 2, 2012 at 12:31 AM, Worik R <worikr at gmail.com>
wrote:
What I mean is how do I get the R compilation or execution
process to spit
out a line number with errors and warnings?
Indeed, I often suffer from the same problem when debugging R
code too.
This is a real issue for me.
As Duncan mentioned already, you can't *always* get a line
number. You
can, however, usually get enough context around the failing call
for
you to be able to smoke the problem out.
What are the cases where you cannot get line numbers? Duncan
said
source()ed code comes with line numbers, but what's the more
general
rule?
The general rule is that parse() needs to be called with the
"srcfile"
argument set to a srcfile object. source() does that by default.
OK. But isn't it technically possible to compute a line number even
when
no source file is present?
Yes, you don't really need to have a file present, you just need a
srcfile object. For example, on Windows when you use
source("clipboard"), there's no file, just the system clipboard.
If you call fix() on any function, you will
get something like a source file even if srcfile was not set.
Yes, and then you can call source on that object, and you'll get line
number information attached, relative to whatever you sourced. So it
could make sense to have a line number referring to what you would
see
in fix(). Or at least, the last executed line when calling
browser() or
when using options(error=recover), like gdb does.
The thing is that if you didn't attach the line number information to
the code, then it's not there. R can't figure out after the fact
where
the code came from. It needs to have the debug info in place when it
runs it. How could R figure out where some expression came from that
it
happens to be executing? Using eval() on a constructed expression in
a
function is not all that uncommon, but to the evaluator, it looks
just
like any other evaluation.
OK.
This could be especially useful for packages that were not
installed
with keep.source=TRUE. It could even help getting more useful
error
messages on R-help...
If you're debugging a package, then why not install it with keep.source=TRUE?
Of course. I just wondered whether this step could possibly be avoided. It can be useful to have debugging details when casual users report a bug, without reinstalling the package. Not a big deal, though. Regards ______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Confidentiality Statement: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message.