On 24/04/2014, 5:26 PM, Henrik Bengtsson wrote:
On Thu, Apr 24, 2014 at 1:42 PM, Duncan Murdoch
<murdoch.dun...@gmail.com> wrote:
On 24/04/2014, 1:11 PM, Yihui Xie wrote:

Hi,

I guess the backslash should not be used as the separator for
strsplit() in compareVersion(), because the period in [.] is no longer
a metacharacter (no need to "escape" it using a backslash):

https://github.com/wch/r-source/blob/trunk/src/library/utils/R/packages.R#L866-L867

compareVersion

function (a, b)
{
....
      a <- as.integer(strsplit(a, "[\\.-]")[[1L]])
      b <- as.integer(strsplit(b, "[\\.-]")[[1L]])
....
<environment: namespace:utils>


Could you post an example where this causes trouble, or are you just
suggesting this as a way to make the source a little cleaner?

Maybe it's already clear, but [\\.] is the set for the two symbols '\'
and '.', not '.' alone.  For example, I would expect an error below:

compareVersion("3.14-59.26", "3.14-59\\26")
[1] 0


How does that cause problems?

Duncan Murdoch

/Henrik




A similar regular expression problem also exists in the Sweave syntax
(for \Sexpr{}), and I have reported it once. It was fixed but the fix
was immediately reverted for some reason:

https://github.com/wch/r-source/commit/52b0a46e15136a7f9e4777e9960fdda6d84880c0


A link to your report would be more useful, if it included an example where
the bad regexp causes trouble.

Duncan Murdoch


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