From: "stephan.zimmer" <stephan.zimmer@...>
Date: 2008-11-28T02:10:15+09:00
Subject: Ruby's duck typing

I would like to represent certain data by a list; to this end I let
class SomeData inherit from Array:

    class SomeData < Array
        def get_field
            self[2]
        end
    end

(I want to keep it simple, therefore, the example might look silly.)
Since the "get_field" method is not universal I don't want to reopen
class "Array". If I write

    SomeData.new([1,2,3]).get_field

everything is fine. If I, however, try to do

    [1,2,3].get_field

I get an exception "NoMethodError", which, of course, is not
surprising.

My question is: is there a way around this, that is, to simply write
[1,2,3] to denote a constant of type "SomeData" instead of always
writing "SomeData.new([1,2,3])" (without reopening Array)?

Thanks a lot,

Stephan