are arithmetic comparison operators binary?
Martin Maechler wrote:
>> 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 )
point taken.
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
ok.
WK> plus those undocumented, but assumed by the developers. ;-) :-) Indeed, we are also grateful for (concise!) patches to man/*.Rd help files.
ok.
>> 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.
not quite sure what you mean by 'closeness to mathematical notation' here.
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
which is consistent with NULL + 1. btw: 1. you might want to keep the error message from applying < and other relops to an inappropriate number of arguments in sync with the message one gets from, e.g., '+'(1,2,3). (you may want to actually update the message from '+' and relatives, as it seems that there are more operators that give an error message similar to that of '<'. the attached patch fixes this; it has been compiled and successfully tested -- see below.) 2. '+'() and '+'(1,2,3) say the operator needs one or two arguments, but again, '+' is documented as a *binary* operator. i guess the intention here is to have them unary or binary, and it's the docs that should be updated. vQ The patch for src/main/arithmetic.c was prepared as follows: svn co https://svn.R-project.org/R/trunk/ cd trunk tools/rsync-recommended # modifications made to src/main/character.c svn diff > do_grep.diff The patched sources were successfully compiled and tested as follows: svn revert -R . patch -p0 < do_grep.diff ./configure make make check -------------- next part -------------- A non-text attachment was scrubbed... Name: arithmetic.diff Type: text/x-diff Size: 509 bytes Desc: not available URL: <https://stat.ethz.ch/pipermail/r-devel/attachments/20090224/d06f659d/attachment.bin>