[Rd] asmode.integer() -- RFC

[Prof Brian Ripley]

> From: Martin Maechler <maechler@stat.math.ethz.ch>
> Date: Thu, 7 Sep 2000 15:12:14 +0200 (CEST)

 
> >>>>> "Bill" == Bill Venables <Bill.Venables@cmis.csiro.au> writes:
> 
>     Bill> At 10:17 07/09/00 +0200, Martin Maechler wrote:
>     >> Many of us known that sometimes, e.g. in calls to .C(..), you want to
>     >> basically say
>     >> 
>     >> x <- as.integer(x)
>     >> 
>     >> but you can't do that because as.vector() 
>     >> and it's descendants such as as.integer, as.double, as.character
>     >> drop all attributes.
>     >> 
>     >> Several months ago, someone proposed to use a new function
>     >> As.integer() instead.  
>     >> Since I just now again "stumbled" on it, I wondered if it might be 
worth to
>     >> define 
>     >> 
>     >> asmode.integer   <- function(x) { mode(x) <- "integer"   ; x }
>     >> asmode.double    <- function(x) { mode(x) <- "double"    ; x }
>     >> asmode.character <- function(x) { mode(x) <- "character" ; x }
> 
>     Bill> The idiom in "another place" is
> 
>     Bill>  storage.mode(x) <- "integer"
>     Bill>  storage.mode(x) <- "double"  &c
> 
> I had this initially, but
> 
>     Bill> my preference would again be for convergence of the two dialects.

> well, in R, "mode<-" and "storage.mode<-" are 100% equivalent.

What the help page says is

     The two assignment versions are currently identical.
                                     ^^^^^^^^^

and I am not sure we want that to remain so, nor should we assume so.
I think R's use of all of mode and typeof and storage.mode is confusing,
especially as the first and third are diluted versions of the second.
(Without looking, how many of you know the exact differences?)


asmode.integer(x)  and (storage.mode(x) <- "integer"; x)  seem to be to
just be (in R) cumbersome ways to do

structure(as.integer(x), attributes(x))

> in Splus 5.1, for the above case, they behave equivalently as well.
> Hence, saving the extra  "storage." seemed feasible to me, and since I'm
> occasionally fond of `minimal art' ......
> 
> I agree that "storage.mode" is more expressive...
> 
>     Bill> (Of course when S4 takes over that other place, this sort of
>     Bill> consideration becomes much less relevant.)
> 
> (true, unfortunately)

Sooner than you might think.  What was announced as the last ever
release of a version of S-PLUS based on Svr3 was released a few days ago.
The future there is S-PLUS 6.x and Svr4 only.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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