On 23/01/2011 11:50 AM, peter dalgaard wrote:
On Jan 22, 2011, at 21:08 , Vitalie S. wrote:
The only definite argument occurred in the thread against "+" operator
was the lack of commutativity (as if one have to prove algebraic
theorems in R).
I think the real killer was associativity, combined with coercion rules:
Is "x"+1+2 supposed to be equal to "x12" or "x3"?
As I pointed out at the time, we don't even have associativity for
integer addition. For example in
-1L + .Machine$integer.max + 1L
the two possibilities
(-1L + .Machine$integer.max) + 1L
and
-1L + (.Machine$integer.max + 1L)
give different results. When I try it now without parentheses, I get
the same answer as the first one, but I don't believe we guarantee that
that will always be so.
Duncan Murdoch
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
