On Thu, 14 Apr 2005, François Pinard wrote:

[Prof Brian Ripley]
[François Pinard]

Now using this line within `~/.Renviron':
 R_LIBS=/home/pinard/etc/R
my tiny package is correctly found by R.  However, R does not seem to
see any library within that directory if I rather use either of:
 R_LIBS=$HOME/etc/R
 R_LIBS="$HOME/etc/R"

Correct, and as documented.  See the description in ?Startup,
which says things like ${foo-bar} are allowed but not $HOME, and
not ${HOME}/bah or even ${HOME}.  But R_LIBS=~/etc/R will work in
.Renviron since ~ is intepreted by R in paths.

Hello, Brian (or should I rather write Prof Ripley?).

Thanks for having replied.  I was not sure how to read "but not", which
could be associated either with "which says" or "are allowed".  My
English knowledge is not fully solid, and I initially read you meant the
later, but it seems the former association is probably the correct one.

It does not say. You have gone beyond what it says is allowed.


The fact is the documentation never says that `$HOME' or `${HOME} are forbidden. It is rather silent on the subject, except maybe for this sentence: "value is processed in a similar way to a Unix shell" in the Details section, which vaguely but undoubtedly suggests that `$HOME' and `${HOME}' might be allowed. Using `~/' is not especially documented either, except from the Examples section, where it is used. I probably thought it was an example of how shell-alike R processes `~/.Renviron'.

Yes, it is silent. And silence means it is not documented to work.

The last writing (I mean, something similar) is suggested somewhere in
the R manuals (but I do not have the manual with me right now to give
the exact reference, I'm in another town).

It is not mentioned in an R manual, but it is mentioned in the FAQ.

I tried checking in the FAQ. By the way, http://www.r-project.org presents a menu on the left, and there is a group of items under the title `Documentation'. `FAQs' is shown under that title, but is not clickable. I would presume it was meant to be? However, the `Other' item is itself clickable, and offers a link to what appears to be an FAQs page.

The only thing I saw, in item 5.2 of the FAQ (How can add-on packages be
installed?) says that one may use `$HOME/' while defining `R_LIBS' in a
Bourne shell profile, or _preferably_ use `~/` while defining `R_LIBS'
within file `~/.Renviron`.  The FAQ does not really say that `$HOME' is
forbidden.  The FAQ then refers to `?Startup' for more information, and
`?Startup' is not clear on this thing, in my opinion at least.

R_LIBS=$HOME/etc/R will work in a shell (and R_LIBS=~/etc/R may not).

Another hint that it could be expected to work is that the same
`~/.Renviron' once contained the line:

R_BROWSER=$HOME/bin/links

which apparently worked as expected.  (This `links' script launches
the real program with `-g' appended whenever `DISPLAY' is defined.)

Yes, but that was not interpreted by R, rather a shell script called by R.

Granted, thanks for pointing this out.

The documentation does not really say either (or else I missed it) if
the value of R_BROWSER is given to exec, or given to an exec'ed shell.
If a shell is called, it means in particular that we can use options,
and this is a useful feature, worth being known I guess.

It is platform-dependent, and indeed may change over time on a given platform.


The trick in reading technical documentation is to read what it says, and not assume what it does not say.

--
Brian D. Ripley,                  [EMAIL PROTECTED]
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595
______________________________________________
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

Reply via email to