[R] setValidity and "initialize" method conflict ?

[Thomas Stabla]

Hello,

i am using classes and want to force an validity check when an
object is created.

platform i686-pc-linux-gnu
arch     i686
os       linux-gnu
system   i686, linux-gnu
status
major    1
minor    7.1
year     2003
month    06
day      16
language R


Following piece of code works fine, just like I expected it to
----------
> setClass("Foo", representation(woo = "numeric"))
[1] "Foo"
> validFooObject <- function(object) {
+   if(object at woo > 0) return(TRUE)
+   else return("warning: negative value for woo")}
> setValidity("Foo", validFooObject)
[1] "Foo"
> new("Foo", woo = 1) # all is fine
An object of class "Foo"
Slot "woo":
[1] 1

> new("Foo", woo = -1) # ok, negative value
Error in validObject(.Object) : Invalid "Foo" object: warning: negative
value for woo
---------

Now, if i define a initialize method for Foo, things change (R had
been restarted)

---------
> setClass("Foo", representation(woo = "numeric"))
[1] "Foo"
> validFooObject <- function(object) {
+   if(object at woo > 0) return(TRUE)
+   else return("warning: negative value for woo")}
> setValidity("Foo", validFooObject)
[1] "Foo"
> setMethod("initialize", "Foo", function(.Object, woo){
+   .Object at woo = woo
+   .Object})
[1] "initialize"
> new("Foo", woo = 1) # all is fine
An object of class "Foo"
Slot "woo":
[1] 1

> new("Foo", woo = -1) # ! no warning, object created!
An object of class "Foo"
Slot "woo":
[1] -1
---------

How do i force an validity check, when an initalize method has been
set?
Thanks for your help.

Greetings,
Thomas Stabla
-------------- next part --------------
setClass("Foo", representation(woo = "numeric"))
validFooObject <- function(object) { 
  if(object at woo > 0) return(TRUE)
  else return("warning: negative value for woo")} 
setValidity("Foo", validFooObject)
new("Foo", woo = 1) # all is fine
new("Foo", woo = -1) # ok, negative value
###############################################
setClass("Foo", representation(woo = "numeric"))
validFooObject <- function(object) { 
  if(object at woo > 0) return(TRUE)
  else return("warning: negative value for woo")} 
setValidity("Foo", validFooObject)
setMethod("initialize", "Foo", function(.Object, woo){
  .Object at woo = woo
  .Object})
new("Foo", woo = 1) # all is fine
new("Foo", woo = -1) # ! no warning message is produced !