On Wed, 19 Jul 2006, Martin Maechler wrote:
[most discussion of unix tail behavior deleted]
>
> I know that there is some "good" reason for the behavior of
> 'tail' in "Unix"
> { tail -3 === tail -n 3 and
> tail -3 === tail -n -3 }
>
> but of course, we can't be compatible here, because in S
> (and most reasonable languages :-)
> "3 == +3" and "3 != -3" !
>
Ahhh. But in R
quote( foo( +n ) ) != quote( foo( n ) )
so if one was determined to emulate GNU Coreutils tail's behavior it
***could*** be done by using match.call to recover the explicit '+' or
'-'.
But I shudder to think of the confusion that this approach might cause
when n is an expression whose value is negative.
Chuck
Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:[EMAIL PROTECTED] UC San Diego
http://biostat.ucsd.edu/~cberry/ La Jolla, San Diego 92093-0717
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