slots of type "double"

On Tue, 13 Nov 2007, Prof Brian Ripley wrote:

On Tue, 13 Nov 2007, John Chambers wrote:

What's the proposal here?  To eliminate "double" as a class?  No
objection

Eliminate "double" and "single".

from this corner.  As I remember, it was put in early in the
implementation of methods, when I was confused about what R intended in
this area (well, I'm not totally unconfused even now).

If this is the proposal, we could implement it in r-devel and see if
there are complaints.

I was going to propose so after running some tests over CRAN/BioC (which
will take a few hours).

Which showed up problems in packages Matrix and matlab.

Matrix clearly has a different view of these classes:

## "atomic vectors" (-> ?is.atomic ) --
## ---------------  those that we want to convert from old-style "matrix"
setClassUnion("atomicVector", ## numeric = {integer, double} but all 3
should *directly* be atomic
               members = c("logical", "integer", "double", "numeric",
                           "complex", "raw", "character"))

If I remove "double" there, I get an error in an example:

stopifnot(is(scm, "sparseVector"),

+           identical(cm, as.numeric(scm)))
Error in as(x at x, mode) :
   no method or default for coercing "numeric" to "double"

and looking at the code suggests that "double" is used as the class name
in several places.


Package matlab is simpler: test mkconstarray.R fails at

   > test.mkconstarray(list(class.type = "double", value = pi, size = 4),

rep(pi, 4))
   Error in as(value, match.arg(class.type)) :
     no method or default for coercing "numeric" to "double"

and needs the author to rectify his confusion between "class" and "type".

I'd like to give the Matrix authors a chance to look into this before
making the change.  Loking at the packages has reinforced my impression
that having "double" as an S4 class is only adding confusion, so the
change is desirable.