Try this:
# constructor for Square
makeSquare <- function(name, side) structure(list(name = name, side =
side), class = c("Square", "Shape"))
# generic
getName <- function(shape) UseMethod("getName")
# Shape method
getName.Shape <- function(shape) shape$name
# generic
getArea <- function(shape) UseMethod("getArea")
# Square method
getArea.Square <- function(shape) shape$side ^ 2
sq <- makeSquare("a", 10)
getName(sq) # inherits getName method from Shape class
getArea(sq) # uses getArea method for Square class
On Thu, Sep 4, 2008 at 11:56 PM, <[EMAIL PROTECTED]> wrote:
> Coming from a C++ and C# background I would like to know how inheritance
> works with 'R'. The classical example is I can define an abstract class
> 'Shape' and have an array of 'Shape's but each instance could be a Circle,
> Square, Triangle, etc. because they all derive from 'Shape'. At runtime if I
> wish I can tell the type of the 'Shape' using various language specific
> operators. In 'R' it seems that each 'function' in general returns an object
> that is specific to that function. For example 'stl' returns an 'stl' object,
> 'lm' retuirns an 'lm' object, 'kmeans' returns a 'kmens' object etc. If I
> have an array of these objects what can I use to tell the type of object in
> 'R' and runtime? Any examples would be helpful.
>
> Thank you.
>
> Kevin
>
> ______________________________________________
> [email protected] 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.
>
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and provide commented, minimal, self-contained, reproducible code.
