[R] 'callNextMethod' in a '[<-' function does not work ?

[Martin Morgan]

On 12/09/2011 10:15 AM, cgenolin wrote:
> Hi the list,
>
> I try to use callNextMethod in a setteur ([<-) but it does not work.
> Any raison ?
> Any other option ?
>
> --- 8<  ------------------
> ### Class B0 ###
> setClass("B0" , representation(b0 = "numeric"))
> setReplaceMethod("[","B0",function(x,i,j,value){x at b0<- -value})

return modified x, and match signature to getGeneric("[<-")

setClass("B0" , representation(b0 = "numeric"))

setReplaceMethod("[","B0", function(x,i,j, ..., value) {
     x at b0 <- -value
     x
})

>
> a<- new("B0")
> a at b0<- 3
> a
> a["b0"]<- 3
> a
>
>
> ### Class B1 ###
> setClass("B1", representation(b1 = "character"), contains = "B0")
> setReplaceMethod("[","B1",function(x,i,j,value){
>    value<- value*2
>    callNextMethod()
> })

provide arguments to callNextMethod, reflecting updated value

setClass("B1", representation(b1 = "character"), contains = "B0")

setReplaceMethod("[","B1",function(x,i,j, ..., value){
   value <- value*2
   callNextMethod(x, i, j, ..., value=value)
})


> b<- new("B1")
> try(b["b0"]<- 5)

of course "b0" is not being used to index here.

Martin

> --- 8<  ------------------
>
> Christophe
>
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