On Fri, 17 Nov 2006, Duncan Murdoch wrote:

[...]

> By the way, another complaint is that sum() is supposed to be generic,
> but you can't define a sum.matrix() method so that sum(a,b,c) does the
> same as a+b+c when a is a matrix. (This would probably be a bad idea
> because people may be relying on the current behaviour, but R tries not
> to prevent people from testing out bad ideas.)

In this case it does, and this is as documented in ?Summary, referred to
from ?sum.

--
Brian D. Ripley,            ripley@(protected)
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford,         Tel: +44 1865 272861 (self)
1 South Parks Road,              +44 1865 272866 (PA)
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