An S4 class inheriting from another class with a prototype does not
inherit (at least sometimes) the prototype for .Data:
> setClass("A", "numeric", 1)
> setClass("B", "A")
> new("A")
An object of class "A"
[1] 1
> new("B")
An object of class "B"
numeric(0)
My expectation is that prototype inheritance of .Data behaves as for
regular slots:
> setClass("A",
+ representation=representation(x="numeric"),
+ prototype=prototype(x=1))
[1] "A"
> setClass("B", "A")
[1] "B"
> new("B")
An object of class "B"
Slot "x":
[1] 1
I think this traces first to an errant ! that claims the data part is
filled, when it is not yet, and second to a call to getDataPart with a
primitive that occupies, but does not have, a .Data slot.
Martin
--- src/library/methods/R/RClassUtils.R (revision 41426)
+++ src/library/methods/R/RClassUtils.R (working copy)
@@ -45,7 +45,7 @@
## try for a single superclass that is not virtual
supers <- names(extends)
virtual <- NA
- dataPartDone <- length(slots)==0 || !is.na(match(".Data", snames))
+ dataPartDone <- length(slots)==0 || is.na(match(".Data", snames))
dataPartClass <- if(dataPartDone) "ANY" else elNamed(slots, ".Data")
prototype <- [EMAIL PROTECTED]
## check for a formal prototype object (TODO: sometime ensure that this
happens
@@ -79,8 +79,15 @@
else if(length(slots) > 0) {
for(slotName in slotsi) {
if(identical(slotName, ".Data")) {
- if(!dataPartDone) {
- prototype <- setDataPart(prototype,
getDataPart(pri))
+ if (!dataPartDone) {
+ temp <- getClass(class(pri))@slots
+ if (length(temp)==0 ||
+ is.na(match(".Data", names(temp)))) {
+ prototype <- pri
+ attributes(prototype) <- NULL
+ } else
+ prototype <-
+ setDataPart(prototype, getDataPart(pri))
dataPartDone <- TRUE
}
}
> sessionInfo()
R version 2.6.0 Under development (unstable) (2007-05-03 r41426)
x86_64-unknown-linux-gnu
locale:
LC_CTYPE=en_US;LC_NUMERIC=C;LC_TIME=en_US;LC_COLLATE=en_US;LC_MONETARY=en_US;LC_MESSAGES=en_US;LC_PAPER=en_US;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US;LC_IDENTIFICATION=C
attached base packages:
[1] "stats" "graphics" "grDevices" "utils" "datasets" "methods"
[7] "base"
--
Martin Morgan
Bioconductor / Computational Biology
http://bioconductor.org
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