RE: [Rd] UseMethod call with no arguments - solved, I think

From: Henrik Bengtsson <hb_at_maths.lth.se>
Date: Tue 16 Nov 2004 - 22:54:51 EST


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/
>
> ______________________________________________
> R-devel@stat.math.ethz.ch mailing list
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>
>



R-devel@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel Received on Tue Nov 16 23:01:05 2004

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