I have had that thought myself as well, but don't see any harm in my particular
application. I describe in general terms what I'm trying to do: I have defined
a class for the output of a function that does various calculations. The reason
for this is that I want methods for plotting and printing for the output
object. On the other hand, the output object does include various sub-objects
the access of which is useful for users (basically, the object was a list of
several vectors and numbers, before I decided that I need a class, and in the
class definition, I have defined the elements of the list as slots).
Maybe I could (and should?) have defined the class with just one slot that
contains the list, which would make it behave like I want it immediately.
Regards,
Ulrike Grömping
---------- Original Message -----------
From: Martin Maechler <[EMAIL PROTECTED]>
To: "Ulrike Grömping" <[EMAIL PROTECTED]>
Cc: r-help@stat.math.ethz.ch
Sent: Fri, 18 Nov 2005 18:29:27 +0100
Subject: Re: [R] Method for $
> >>>>> "Ulrike" == Ulrike Grömping <[EMAIL PROTECTED]>
> >>>>> on Fri, 18 Nov 2005 15:37:58 +0100 writes:
>
> Ulrike> Dear R experts,
>
> Ulrike> I have defined a class "myclass" and would like the
> Ulrike> slots to be extractable not only by "@" but also by "$".
>
> hmm, I know this is not what you've asked for, but
> why would you want to do that? To me, it seems a pretty harmful idea
> that only leads to confusion and does not provide sensible
> functionality.
>
> When S4 classes where created, using '@' instead of '@' with a
> *different* meaning was very much on purpose and I think it's a
> bit too ambitious to try being smarter than John Chambers,
> the creator of the S4 object system, on this.
>
> Martin Maechler, ETH Zurich
>
> Ulrike> I now try to write a method for "$" that
> Ulrike> simply executes the request [EMAIL PROTECTED], whenever someone
> calls
> Ulrike> object$slotname for any object of class "myclass".
> Ulrike> ..............................
> Ulrike> ..............................
------- End of Original Message -------
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