I'm curious about why no one has answered my question below. I can't imagine it would be because no one knows how to answer, it must be something basic I am ignorant about. But I have never seen such a pattern, it seems strange to me that a class with an empty definition is automatically virtual, but a class extending it without adding anything is not. I am really puzzled, there must be some design decision behind this, but I can't figure out it's purpose and usefulness.
I'd really appreciate an explanation. Thank you. -- Hun Dear R-ers, I don't understand the following, maybe someone will help me explain: > > setClasss('A') [1] "A" > > new('a') Error in new("a") : trying to generate an object from a virtual class ("a") > > setClass('b', contains='a') [1] "b" > > new('b') An object of class “b” <S4 Type Object> In what way is B more concrete than A so that it's possible do instantiate B but not A? I don't quite get it. B adds nothing to nothing, and yet it's instantiable, while it's base is not. Makes no sense to me. -- Hun ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.