rlee at fpcc.net wrote:>
> I'd trying to subclass the "lm" class to produce a
"mylm" class whose
> instances behave like lm objects (are accepted by methods like summary.lm)
> but have additional data or slots of my own design.
>
> For starters:
>
> setClass("mylm", "lm")
>
> produces the somewhat cryptic:
> Warning message:
> Old-style (``S3'') class "mylm" supplied as a superclass
of "mylm", but no
> automatic conversion will be peformed for S3 classes in:
> .validDataPartClass(cl, name)
>
> What does this imply?
>
I've never mixed S3 and S4 methods, so excuse my ignorance here (and I'm
only answering because I haven't seen another reply).
Since there is no formal definition of a representation of "lm" (an S3
class!): Does it really make sense for you to extend it with S4 methods?
If not, I'd rather use the "old" construct to tell the object
about
inheritance:
class(anymylmobject) <- c("mylm", "lm")
Anyway, what you are looking for is
?setOldClass
in my expectation, as in:
setOldClass(c("mylm", "lm"))
Reading that help file carefully might help.
In particular, you can get a bit of S4 behaviour (e.g. you can defining
S4 Classes and Methods), but you'll "just" get a virtual class, so
the
requested definition of formal slots will be still a problem.
Uwe Ligges