> ... If one still needed backslashes,
> they could then be entered in single quotes, e.g. VAR='c:\users'.
I don't think it matters whether you use single or double quotes -
both will work. Here's a proof of concept on Linux with R 4.1.1:
$ cat ./.Renviron
A=C:\users
B='C:\users'
C="C:\users"
$ Rscript -e "Sys.getenv(c('A', 'B', 'C'))"
A B C
"C:users" "C:\\users" "C:\\users"
/Henrik
On Wed, Oct 27, 2021 at 11:45 AM Tomas Kalibera
<tomas.kalib...@gmail.com> wrote:
>
>
> On 10/21/21 5:18 PM, Martin Maechler wrote:
> >>>>>> Michał Bojanowski
> >>>>>> on Wed, 20 Oct 2021 16:31:08 +0200 writes:
> > > Hello Tomas,
> > > Yes, that's accurate although rather terse, which is perhaps the
> > > reason why I did not realize it applies to my case.
> >
> > > How about adding something in the direction of:
> >
> > > 1. Continuing the cited paragraph with:
> > > In particular, on Windows it may be necessary to quote references to
> > > existing environment variables, especially those containing file
> > paths
> > > (which include backslashes). For example: `"${WINVAR}"`.
> >
> > > 2. Add an example (not run):
> >
> > > # On Windows do quote references to variables containing paths, e.g.:
> > > # If APPDATA=C:\Users\foobar\AppData\Roaming
> > > # to point to a library tree inside APPDATA in .Renviron use
> > > R_LIBS_USER="${APPDATA}"/R-library
> >
> > > Incidentally the last example is on backslashes too.
> >
> >
> > > What do you think?
> >
> > I agree that adding an example really helps a lot in such cases,
> > in my experience, notably if it's precise enough to be used +/- directly.
>
> Yes, I agree as well. I think the Renviron files should be written in a
> way so that they would work the same in a POSIX shell, so e.g.
> VAR="${VAR0}" or VAR="${VAR0}/subdir" are the recommended ways to
> preserve backslashes in VAR0. It is better to use forward slashes in
> string literals, e.g. VAR="c:/users". If one still needed backslashes,
> they could then be entered in single quotes, e.g. VAR='c:\users'.
>
> The currently implemented parsing of Renviron files differs in a number
> of details from POSIX shells, some are documented and some are not.
> Relying only on the documented behavior that is the same as in POSIX
> shells is the best choice for future compatibility.
>
> Tomas
>
> >
> >
> > > On Mon, Oct 18, 2021 at 5:02 PM Tomas Kalibera
> > <tomas.kalib...@gmail.com> wrote:
> > >>
> > >>
> > >> On 10/15/21 6:44 PM, Michał Bojanowski wrote:
> > >> > Perhaps a small update to ?.Renviron would be in order to mention
> > that...
> > >>
> > >> Would you have a more specific suggestion how to update the
> > >> documentation? Please note that it already says
> > >>
> > >> "‘value’ is then processed in a similar way to a Unix shell: in
> > >> particular the outermost level of (single or double) quotes is
> > stripped,
> > >> and backslashes are removed except inside quotes."
> > >>
> > >> Thanks,
> > >> Tomas
> > >>
> > >> > On Fri, Oct 15, 2021 at 6:43 PM Michał Bojanowski
> > <michal2...@gmail.com> wrote:
> > >> >> Indeed quoting works! Kevin suggested the same, but he didnt
> > reply to the list.
> > >> >> Thank you all!
> > >> >> Michal
> > >> >>
> > >> >> On Fri, Oct 15, 2021 at 6:40 PM Ivan Krylov
> > <krylov.r...@gmail.com> wrote:
> > >> >>> Sorry for the noise! I wasn't supposed to send my previous
> > message.
> > >> >>>
> > >> >>> On Fri, 15 Oct 2021 16:44:28 +0200
> > >> >>> Michał Bojanowski <michal2...@gmail.com> wrote:
> > >> >>>
> > >> >>>> AVAR=${APPDATA}/foo/bar
> > >> >>>>
> > >> >>>> Which is a documented way of referring to existing environment
> > >> >>>> variables. Now, with that in R I'm getting:
> > >> >>>>
> > >> >>>> Sys.getenv("APPDATA") # That works OK
> > >> >>>> [1] "C:\\Users\\mbojanowski\\AppData\\Roaming"
> > >> >>>>
> > >> >>>> so OK, but:
> > >> >>>>
> > >> >>>> Sys.getenv("AVAR")
> > >> >>>> [1] "C:UsersmbojanowskiAppDataRoaming/foo/bar"
> > >> >>> Hmm, a function called by readRenviron does seem to remove
> > backslashes,
> > >> >>> but not if they are encountered inside quotes:
> > >> >>>
> > >> >>>
> > https://github.com/r-devel/r-svn/blob/3f8b75857fb1397f9f3ceab6c75554e1a5386adc/src/main/Renviron.c#L149
> > >> >>>
> > >> >>> Would AVAR="${APPDATA}"/foo/bar work?
> > >> >>>
> > >> >>> --
> > >> >>> Best regards,
> > >> >>> Ivan
> > >> > ______________________________________________
> > >> > R-devel@r-project.org mailing list
> > >> > https://stat.ethz.ch/mailman/listinfo/r-devel
> >
> > > ______________________________________________
> > > R-devel@r-project.org mailing list
> > > https://stat.ethz.ch/mailman/listinfo/r-devel
>
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