R-alpha: options(..) vs. .Options // Re(1i) = 2.4976e-307
Martin Maechler <firstname.lastname@example.org>
Thu, 22 May 97 16:41:16 +0200
vector had been introduced a while ago after my suggestion
(see Ross's E-mail below).
.Options$digits is used be default in several print methods (eg print.lm),
however, deparse(.) e.g., uses options()$width, and not .Options$width.
Another problem is that .Options
is still not in the documentation (on-line help).
Before one could add it there, we'd need ``the specs''.
I think the (at least my) idea was that
options(.) queries or sets elements in the .Options list
and all functions -- including the internal ones -- use .Options.
As far as I know, this is what S does.
Currently, this is NOT the case in R.
Ross said a while ago:
>>> From: Ross Ihaka <email@example.com>
>>> Date: Wed, 11 Dec 1996 17:10:59 +1300 (NZDT)
>>> To: Martin Maechler <firstname.lastname@example.org>
>>> Cc: R-testers mailing list <Remail@example.com>
>>> Subject: R-alpha: options() and .Options -- ?
Ross> Martin Maechler writes:
>> This is not a bug report, rather than some remarks as a
>> "request for comments":
>> It is clear that options( foo = bar )
>> sets the option and also updates the builtin() .Options list :
>> > options(myopt = pi)
>> > .Options$my
>>  3.14159265
>> In S-plus, it was (is) possible to use .Options locally in a function
>> frame in order to just affect some options during evaluation of that
Ross> I have made some changes so that such local assignments to .Options
Ross> will work. The down side is that such assignments will also work at
Ross> top level with the changes shadowing the real system options.
Ross> This also may be ok. It would have the advantage that options would
Ross> then be preserved from session to session. Is this a good idea or a
Ross> bad idea?
rather than 0 whereas Im(as.complex(1)) gives 0 as it should.
- Martin Maechler
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