[Rd] Fwd: Using existing envars in Renviron on friendly Windows

[Michał Bojanowski]

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?

On Mon, Oct 18, 2021 at 5:02 PM Tomas Kalibera <tomas.kalibera using 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 <michal2992 using 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.r00t using 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 <michal2992 using 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 using r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel