From: me@...
Date: 2006-11-12T22:00:05+09:00
Subject: redefining a method using Module#include

Hi,

How can I redefine Array#[] using an included Module?  Here is my
attempt:

module AbsenceHandling
    def if_absent_call(p)
        @if_absent = p
        self
    end

    def [](index)
        result = old_accessor(index)
        if(result.nil? && !@if_absent.nil?)
            result = @if_absent.call(index)
            self[index]=result
        end
        result
    end
end

class Array
    alias :old_accessor :[]
    include AbsenceHandling
end


x = [1,2,3].if_absent_call(proc{|index|
    "#{index}"
})
puts x[5]


Thanks very much,
Mike