>>>>> "WK" == Wacek Kusnierczyk <waclaw.marcin.kusnierc...@idi.ntnu.no>
>>>>> on Mon, 23 Feb 2009 19:29:31 +0100 writes:
WK> Martin Maechler wrote:
>>>>>>> "WK" == Wacek Kusnierczyk <waclaw.marcin.kusnierc...@idi.ntnu.no>
>>>>>>> on Mon, 23 Feb 2009 12:06:32 +0100 writes:
>>>>>>>
>>
>> Thank you, Wacek,
>> though .. "wrong mailing list"
>>
WK> apologies. i was actually asking for explanation, assuming that it
WK> might be my misunderstanding, rather than reporting a bug.
( yes; but it is really a technical topic, also touching on
extending R [below], hence --> R-devel )
WK> the man page for relational operators (see, e.g., ?'<') says:
WK> "
WK> Binary operators which allow the comparison of values in atomic vectors.
>>
WK> Arguments:
>>
WK> x, y: atomic vectors, symbols, calls, or other objects for which
WK> methods have been written.
WK> "
>>
WK> it is somewhat surprizing that the following works:
>>
WK> '<'(1)
WK> # logical(0)
>>
WK> '<'()
WK> # logical(0)
>>
WK> '<'(1,2,3)
WK> # TRUE
>>
>> a bit surprising (sic!), indeed, even for me.
>> Thanks for your notice and report!
>>
WK> you're welcome.
WK> shouldn't the tests have captured it? i think you should have a check
WK> for every feature following from the docs.
yes, we should.
>> R is free software and comes with ABSOLUTELY NO WARRANTY.
>> You are welcome to ......................
>> .............
>> R is a collaborative project with many contributors.
I think we'd gladly accept well-written & commented extra
<R-x.y.z>/tests/foo.R
files or patches to existing ./tests/*.R
particularly if the contributor shows the new tests are
systematically covering currently untested areas...
Again: this really belongs to R-devel
--> I'm CCing there {and write a quick reply on R-help about
the mailing list redirection}
WK> plus those undocumented, but assumed by the developers.
;-) :-)
Indeed, we are also grateful for (concise!) patches to man/*.Rd
help files.
>> If you'd looked a bit in the sources, you'd seen that they
>> really are supposed to be binary only.
>>
WK> it wouldn't be nonsensical to let them be of arbitrary arity (in a
WK> well-documented manner), though it might confuse users.
Yes (to the latter). One of the beauties of S and R is the
syntax closeness to mathematical notation.
Many of us know that Lisp has beauties that S can never have,
but that's really in different beauty-space.
>> A very small change in the sources does accomplish this, passes
>> the standard checks (and I cannot imagine reasonable code that
>> would have relied on the more lenient behavior), so
>> this will have changed in one of the next versions of R-devel.
>>
WK> thanks.
WK> just a question (i haven't checked the sources, maybe i should): what
WK> is it that happens when one of the operators is called with n = 0 or 1
WK> argument? how does it come up with logical(0) rather than NA?
In some of the cases e.g.
'<'(1)
it basically does [empty] < 1 and hence returns the same as
NULL < 1
Regards,
Martin Maechler, ETH Zurich
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