[Rd] UseMethod call with no arguments - solved, I think
hb at maths.lth.se
Tue Nov 16 12:54:51 CET 2004
Hmmm, to follow up on my own question; it is likely that I have
misunderstood the update note. Now, I read it as
foo <- function(x, ...) UseMethod()
is deprecated and that
foo <- function(x, ...) UseMethod("foo", x)
( or foo <- function(x, ...) UseMethod("foo") )
should be used.
My concern/interpretation was that
bar <- function(...) UseMethod("bar")
is deprecated (where I saw "..." as the "arguments"). Reading ?UseMethod
more carefully (it still says) - "If it is called with just one argument,
the class of the first argument of the enclosing function is used as
'object': unlike S this is the actual argument passed and not the current
value of the object of that name." - I see that the above should still be
So, now the note makes perfectly sense and it is *not* a "big step".
> -----Original Message-----
> From: r-devel-bounces at stat.math.ethz.ch
> [mailto:r-devel-bounces at stat.math.ethz.ch] On Behalf Of
> Henrik Bengtsson
> Sent: Monday, November 15, 2004 7:54 PM
> To: R-devel at r-project.org
> Subject: [Rd] UseMethod call with no arguments
> Dear R developers,
> I will ask a very straightforward question concerning
> UseMethod's future, because people depending on my code
> wonder what will happen to it next.
> In R v2.0.1 NEWS it says
> o The undocumented use of UseMethod() with no argument is now
> formally deprecated.
> and in the R v2.0.1 help(UseMethod) it says
> 'UseMethod' accepts a call with no arguments and tries to deduce
> the generic from the context. This was undocumented on the help
> page and is now deprecated. It is allowed but 'strongly
> discouraged' in S-PLUS.
> The short question is: UseMethod() with no arguments is
> deprecated. Typically, after making something deprecated it
> will later become defunct. Do you have any plans for when
> this will happen? Are we talking months, years or in reality
> never? A version number?
> Second, in R v2.0.0 NEWS there was nothing on making
> UseMethod() without arguments deprecated (the latest patched
> version I have is dated October 21st). As I believe a rather
> big step has been taken, I am somewhat surprised that I
> haven't seen it discussed. Was there a discussion taking
> place elsewhere that I missed, or is it an "obvious" update?
> Finally, many thanks for making R (the software, the help,
> the community,
> ...) to what it is.
> Best wishes
> Henrik Bengtsson
> Dept. of Mathematical Statistics @ Centre for Mathematical Sciences
> Lund Institute of Technology/Lund University, Sweden (+2h UTC)
> +46 46 2229611 (off), +46 708 909208 (cell), +46 46 2224623 (fax)
> h b @ m a t h s . l t h . s e, http://www.maths.lth.se/~hb/
> R-devel at stat.math.ethz.ch mailing list
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