R devel - Nov 2010 - reference classes: question on inheritance

Dear list,

I have a reference class which should act as a "generic" superclass
for
other classes. I've read the respective section at ?setRefClass and put the
name of the superclass to the 'contains' argument of an example subclass
(see class defs below). Classnames are set in a way that shouldn't result in
collation issues (virtual def sourced before superclass def sourced before
subclass). Yet, this  results in the following error:

Warnmeldung:
unable to find a consistent ordering of superclasses for class
"Shabubu":
order chosen is inconsistent with the superclasses of "JObject"

###### CLASS DEFS #####
setClass("JObjectVirtual")
setRefClass(
	Class="JObject",
	fields=list(
		# GENERIC FIELDS (DON'T CHANGE !!!)
		.BUFFER="environment",
		.GENESIS="environment",
		.HISTORY="environment",
		.IMAGES="environment",
		.LOGS="environment",
		.OPTS="environment",
		.PLUGINS="environment",
		.TMP="environment",
		.UID="character",
		DATA="data.frame"
		# /
	),
	contains=c("JObjectVirtual"),
 	methods=list(
		...
	)
)
setRefClass(
	Class="Shabubu",
	fields=list(
		# CUSTOM FIELDS (ADAPT TO YOUR NEEDS)
		a="numeric",
		b="character",
		c="logical",
		d="data.frame",
		e="matrix",
		f="list",
		derived.field="function"
		# /
	),
	contains=c("JObject")
)

What am I doing wrong here?

Thanks,
Janko

Hmm, interesting: it's the virtual class that causes the trouble. If a
virtual class is a ref class, everything works fine. If it's a standard S4
class, it results in the error below.

Regards,
Janko
> -----Urspr?ngliche Nachricht-----
> Von: Janko Thyson [mailto:janko.thyson at ku-eichstaett.de]
> Gesendet: Montag, 22. November 2010 00:31
> An: 'r-devel at r-project. org'
> Betreff: reference classes: question on inheritance
> 
> Dear list,
> 
> I have a reference class which should act as a ?generic? superclass for
> other classes. I?ve read the respective section at ?setRefClass and put
> the name of the superclass to the ?contains? argument of an example
> subclass (see class defs below). Classnames are set in a way that
> shouldn?t result in collation issues (virtual def sourced before
> superclass def sourced before subclass). Yet, this  results in the
> following error:
> 
> Warnmeldung:
> unable to find a consistent ordering of superclasses for class
> "Shabubu": order chosen is inconsistent with the superclasses of
> "JObject"
> 
> ###### CLASS DEFS #####
> setClass("JObjectVirtual")
> setRefClass(
> 	Class="JObject",
> 	fields=list(
> 		# GENERIC FIELDS (DON'T CHANGE !!!)
> 		.BUFFER="environment",
> 		.GENESIS="environment",
> 		.HISTORY="environment",
> 		.IMAGES="environment",
> 		.LOGS="environment",
> 		.OPTS="environment",
> 		.PLUGINS="environment",
> 		.TMP="environment",
> 		.UID="character",
> 		DATA="data.frame"
> 		# /
> 	),
> 	contains=c("JObjectVirtual"),
>  	methods=list(
> 		...
> 	)
> )
> setRefClass(
> 	Class="Shabubu",
> 	fields=list(
> 		# CUSTOM FIELDS (ADAPT TO YOUR NEEDS)
> 		a="numeric",
> 		b="character",
> 		c="logical",
> 		d="data.frame",
> 		e="matrix",
> 		f="list",
> 		derived.field="function"
> 		# /
> 	),
> 	contains=c("JObject")
> )
> 
> What am I doing wrong here?
> 
> Thanks,
> Janko