[Rd] index.search

[Martin Maechler]

>>>>> Adrian Dușa <dusa.adrian at unibuc.ro>
>>>>>     on Mon, 16 Jun 2014 08:33:59 +0300 writes:

    > On Mon, Jun 16, 2014 at 6:37 AM, Gabriel Becker
    > <gmbecker at ucdavis.edu> wrote:
    >> [...]  You can. This is valid R source, so the parser
    >> will understand it
    >> 
    >> expr = parse(text= example("deMorgan", package="QCA",
    >> give.lines=TRUE))
    >> 
    >> You can then evaluate some or all of that expression
    >> using either R's own eval package or, e.g. Hadley
    >> Wickham's evaluate package (for your particular usecase
    >> evaluate will be easier I think).

    > Oh, I see...! In that case I can use it, of course.  Did
    > install the evaluate package, although one would expect
    > some better documentation (no examples at all, especially
    > at the main evaluate function).


    >>> [...]
    >> index.search is an unexported function, which means that
    >> it is subject to change in how it behaves without notice
    >> or even externally available reasons. You can get it via
    >> :::, but again, it's really not the right tool here, and
    >> not safe to use in general in code you expect to keep
    >> working.

    > Yes, I figured that much.  Of course it's not meant to be
    > used in any decently working code, but I learn heavily by
    > simply looking at these sort of (hidden) R functions.

    > Thanks again, Adrian

Apropos "not the right tool".  I'm a bit astonished that nobody
mentioned the fact R already provides "the tool" to
automatically compare all example outputs with a previous
version (of the packages example outputs):

*THE* manual (every package writer should know about,
 re-read/browse about once a year, and search in for such questions):

"Writing R Extensions", section Package subdirectories
----------------------------
(e.g. on the CRAN master in Vienna,
 http://cran.r-project.org/doc/manuals/R-exts.html#Package-subdirectories )
says

|    If directory 'tests' has a subdirectory 'Examples' containing a file
|    'PKG-Ex.Rout.save', this is compared to the output file for running the
|    examples when the latter are checked. 

So: After an 'R CMD check <PKG>' you only need to take and
keep the  <PKG>-Ex.Rout  file that is produced (in the
PKG.Rcheck/ directory), and save it into <PKG>/tests/<PKG>-Ex.Rout.save
and from then on, every time you run R CMD check <PKG>  the
comparison will be made. 

Martin Maechler, ETH Zurich