[Rd] Interpretation of escaped characters in \examples{}

Gordon Smyth smyth at wehi.edu.au
Sat May 24 20:30:36 MEST 2003

I've noticed a curious interpretation of escaped characters in \examples{} 
in .Rd files.

For example, if I type

     files <- dir(pattern="\\.txt")

at the R prompt, I will get a vector containing all file names in the 
current directory containing the string ".txt". If I put

     \examples{ files <- dir(pattern="\\.txt") }

in an .Rd file of a package, then the generated documentation will replace 
my command with


     files <- dir(pattern="\.txt")

i.e., the escaped backslash has been interpreted into a single backlash. If 
a user types example(myfun) at the R prompt, where myfun is the topic alias 
of the .Rd file, then they will actually get

     files <- dir(pattern=".txt")

i.e., the backslash is interpreted a second time.

This seems an undesirable feature. What is in the .Rd file, what is 
displayed in the online help, and what is generated by
example() are all different commands. I had expected anything in 
\examples{} to be reproduced in the online help and by \example{} entirely 
literally with no intepretation.

I am using R 1.7.0pat under Windows 2000 Professional.

Dr Gordon K Smyth, Senior Research Scientist, Bioinformatics,
Walter and Eliza Hall Institute of Medical Research,
1G Royal Parade, Parkville, Vic 3050, Australia
Tel: (03) 9345 2326, Fax (03) 9347 0852,
Email: smyth at wehi.edu.au, www: http://www.statsci.org

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