Message-ID: <18722.49097.70529.650997@stat.math.ethz.ch>
Date: 2008-11-18T13:14:49Z
From: Martin Maechler
Subject: assign("FALSE", TRUE)
In-Reply-To: <4921F798.6010006@biostat.ku.dk>
>>>>> "PD" == Peter Dalgaard <p.dalgaard at biostat.ku.dk>
>>>>> on Tue, 18 Nov 2008 00:00:40 +0100 writes:
PD> Martin Maechler wrote:
>> But in spite of all that I agree that I'd have liked
>> `FALSE` <- <whatever> to signal an error about the fact
>> that it is a reserved word.
>>
RT> This is clearly not a very important issue, but it might
RT> bear some thinking about.
>>
>> Yes. I'd propose that R-core look into how to make
>> assignment to a reserved word an error.
PD> I disagree. In a sense, this is the point of having the
PD> backtick operator: allowing you to work with names that
PD> would otherwise be syntax errors (notice that such names
PD> are sometimes created outside your control, e.g. via
PD> column names in data frames). If you start disallowing
PD> some of them again, well, that way lies madness!
No, no. I'm not against allowing names that are otherwise syntax
errors. They were always possible via assign().
I just am convinced we should not allow reserved words.
{ S / S-plus does not either and gives a nice error message:
S> assign("FALSE", TRUE)
Problem: The name "FALSE" is reserved -- assignments to it are not allowed
}
Martin