R help - Jun 2005 - classes with chron slots

I'd like to define a class with a chron slot, but:

R> require(chron)
R> setClass("myclass", representation(datetime =
"chron"))
[1] "myclass"
Warning message:
undefined slot classes in definition of "myclass": datetime(class
"chron")
in: .completeClassSlots(ClassDef, where)

How should such a class be defined?

Sebastian
-- 
Sebastian P. Luque

>>>>> "Sebastian" == Sebastian Luque <spluque at
gmail.com>
>>>>>     on Wed, 22 Jun 2005 15:50:50 -0500 writes:
    Sebastian> I'd like to define a class with a chron slot, but:
    R> require(chron)
    R> setClass("myclass", representation(datetime =
"chron"))
    Sebastian> [1] "myclass"
    Sebastian> Warning message:
    Sebastian> undefined slot classes in definition of "myclass":
datetime(class "chron")
    Sebastian> in: .completeClassSlots(ClassDef, where)

    Sebastian> How should such a class be defined?

You need to first make "chron" into a (pseudo-) S4 class, 
using  setOldClass()  

Then you can extend it or use it as slot class.

Martin Maechler, ETH Zurich