R devel - Nov 2004 - 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/

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
fine.

So, now the note makes perfectly sense and it is *not* a "big step".

Best wishes

Henrik

> -----Original Message-----
> From: r-devel-bounces@stat.math.ethz.ch 
> [mailto:r-devel-bounces@stat.math.ethz.ch] On Behalf Of 
> Henrik Bengtsson
> Sent: Monday, November 15, 2004 7:54 PM
> To: R-devel@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/
> 
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> R-devel@stat.math.ethz.ch mailing list 
> https://stat.ethz.ch/mailman/listinfo/r-devel
> 
>