[Rd] returning information from functions via attributes rather than return list

[Hadley Wickham]

> Attributes are slightly harder to work with, so Simon's recommendation is
> good advice.  But in cases where you want other functions to work with the
> result, and the result isn't a named list with a class, then attributes are
> a convenient way to go.
>
> The only two snags I can think of are 1, that R uses a few attributes for
> its own purposes (e.g. "names", "dim" and "dimnames") and if you use those
> attribute names for something incompatible you'll probably run into all
> sorts of problems and 2, that S4 objects use attributes internally.  I
> wouldn't recommend using attributes on an S4 object.

Attributes are also useful when you're extending a atomic vector, and
want to be able to store objects of your new class inside data frames
etc.

Hadley

-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/