[Rd] all.equal() improvements (PR#8191)

[Prof Brian Ripley]

Martin,

I have some tests running over CRAN now (RUnit has also failed), but have 
already noticed things like

> swiss[, 1] -> x
> names(x) <- rownames(swiss)
> all.equal(x, x[1:10])
[1] "Names: Lengths (47, 10) differ (string compare on first 10)"
[2] "Numeric: lengths (47, 10) differ"

which is telling me the obvious, with the result that the reports from 
e.g. rpart are cluttered to the detriment of legibility.

I think we need to think harder about what should be reported when the
objects differ in mode or length.

Brian

On Mon, 2 Jan 2006 maechler at stat.math.ethz.ch wrote:

> I'm "happy" to have found the first problem myself:
>
> 'Matrix' doesn't pass R CMD check  anymore with the change I had
> committed:

I am seeing a problem in setGeneric which stops it being installed.

>
> Basically because of this:
>
>  > all.equal(cbind(1:5), matrix(1:5, 5,1, dimnames=list(NULL,NULL)))
>  [1] "Attributes: < Names: Lengths (1, 2) differ (string compare on first 1) >"
>  [2] "Attributes: < Length mismatch: comparison on first 1 components >"
>
> This new behavior is "S-compatible" insofar as S-plus 6.1 also
> returns non-TRUE.
>
> Is this what we want?
> {we'll see soon how many other CRAN packages are having problems for it}
>
> In my intuition, I'd have liked all.equal()  to return TRUE for the above,
> since in principle,  dimnames = NULL  or dimnames = list(NULL,NULL)
> is a trivial difference.
> OTOH, it will need "special case" code to assure this, and I
> wonder if that's worth it.
>
> Please comment!
> Martin
>
>>>>>> "MM" == Martin Maechler <maechler at stat.math.ethz.ch>
>>>>>>     on Mon,  2 Jan 2006 18:00:15 +0100 (CET) writes:
>
>    MM> I've now finally finalized my work on a subset of Andy's
>    MM> propositions, and committed it to R-devel.
>
>    MM> The current change doesn't show in our own checks and
>    MM> examples, but may well in other people's package checks.
>    MM> For this reason, I've also added a line to the
>    MM> 'USER-VISIBLE CHANGES' part of the NEWS file.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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