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
>> > ______________________________________________
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>> > https://stat.ethz.ch/mailman/listinfo/r-devel
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