On 2010-04-13 6:50, Duncan Murdoch wrote:
On 12/04/2010 7:14 PM, Kuhn, Alexandre (NIH/NIA/IRP) [V] wrote:
Hi,

source(file,echo=T) will not echo the last comment in "file" if it is
the last line in the file.
For instance, when sourcing a file containing the following lines

#comment 1
a<-1
#comment 2

R will echo

> #comment 1
> a<-1

What is the solution to have R echo all of the comment lines?
I think the only current solution is to have all the comment lines ahead
of code lines. R doesn't specifically echo the comments, it only echoes
the code, but comments that happen to precede the end of the code line
are echoed as part of that line.

It might be worthwhile making 'skip.echo = n' an error for any
negative n.

Funny things can happen; try these lines:

 #comment 1
 a <- 1
 #comment 2
 b <- 2
 #comment 3
 #comment 4
 d <- 3
 #comment 5

with

 source(file, echo = TRUE, skip.echo = -n)

for n %in% 1:7

 -Peter Ehlers

Specific context:
This problem arises e.g. in the context of help files (.Rd) whose
example section contains only code that is not to be run (\dontrun
markup). Running the function example() (that itself calls
source(,echo=TRUE)) on such a file will not display anything (because
the code is commented out in the corersponding files in R-ex). Is that
the desired behavior of example() or is there a workaround (i.e. to be
able write help files with only dontrun code but that will
nevertheless echo the examples)?

I'm not sure we really want to show all the \dontrun examples, but I'll
look into this, because as documented, they should be shown. (My
preference would be to completely hide the \dontrun lines in example(),
but that's not what is documented to happen, and that's not what happens
when they are followed by code.)

Duncan Murdoch

Thank you,
Alexandre Kuhn



> sessionInfo()
R version 2.10.1 (2009-12-14) i386-apple-darwin9.8.0
locale:
[1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats graphics grDevices utils datasets methods base
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______________________________________________
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PLEASE do read the posting guide
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and provide commented, minimal, self-contained, reproducible code.



--
Peter Ehlers
University of Calgary

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and provide commented, minimal, self-contained, reproducible code.

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