R devel - Apr 2014 - The regular expressions in compareVersion()

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>

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

Regards,
Yihui
--
Yihui Xie <xieyihui at gmail.com>
Web: http://yihui.name

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?
>
> 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