[Rd] last user argument missing from Rscript --verbose

[Scott Kostyshak]

On Fri, Sep 19, 2014 at 8:12 AM, Martin Maechler
<maechler at stat.math.ethz.ch> wrote:
>>>>>> Harris A Jaffee <hj at jhu.edu>
>>>>>>     on Thu, 18 Sep 2014 19:32:29 +0200 writes:
>
> (using  HTML, please don't )
>
>    > The loop that echoes the arguments almost always stops too soon.  It
>    > apparently does that to avoid
>    > echoing the "--args" (that had been inserted) when there are no user
>    > arguments.  However, when there
>    > are user arguments, the next element of the 'av' array is the last
>    > argument and usually not "--args",
>    > although it can be.
>    > ?Rscript is a little sketchy:
>    >      `--verbose' gives details of what `Rscript' is doing.  Also passed
>    >           on to R.
>    > What is passed to R is correct, but the diagnostic is not:
>    >  $ Rscript --verbose /dev/null 1 2
>    >   running
>    >   '/path_to_R --slave --no-restore --file=/dev/null --args 1'
>    > Fixed (only tested on Mac):
>    >  $ Rscript --verbose /dev/null 1 2
>    >   running
>    >   '/Library/Frameworks/R.framework/Versions/3.1/Resources/bin/R --slave
>    > --no-restore --file=/dev/null --args 1 2'
>
> You are right about the problem, also reproducible on Linux.
> You mention a 'fix'.
> It looks to me that is just
>
> -       for(i = 1; i < ac-1; i++) fprintf(stderr, " %s", av[i]);
> +       for(i = 1; i < ac; i++) fprintf(stderr, " %s", av[i]);
>
> in unix/Rscript.c, right ?

Yes, I suggested the same patch here:
http://r.789695.n4.nabble.com/patch-Rscript-off-by-one-error-in-output-td4693780.html

Scott

> BTW: If one use  -e 'commandArgs()'  instead of   /dev/null one
> sees that Rscript's "lying" about the last argument is not
> helpful anyway :
>
>   Rscript --verbose -e 'commandArgs()'
>
>   running
>     '/usr/local64.sfs/app/R/R-3.1.1-inst/bin/R --slave --no-restore -e commandArgs()'
>
>   [1] "/usr/local64.sfs/app/R/R-3.1.1-inst/bin/exec/R"
>   [2] "--slave"
>   [3] "--no-restore"
>   [4] "-e"
>   [5] "commandArgs()"
>   [6] "--args"
>
> because the '--args' appears anyway and indeed *is* passed to 'R'...
>
> A better fix would rather suppress that; but I will commit the
> above change.


--
Scott Kostyshak
Economics PhD Candidate
Princeton University