From: "Peña, Botp" <botp@...>
Date: 2008-04-29T18:41:36+09:00
Subject: Re: Array#first is not Array#[0]

From: Fredrik [mailto:fredjoha@gmail.com] 
# I'm sorry, I think I am too vague about what I want to achieve. What I
# want is to have is an "array" that behaves exactly like an array
# EXCEPT that each element has some text attached to it. Array#size is
# not an element but Array#last is an element for example.
# Maybe it's not doable in any other way than copying the text into each
# element since I would like this text to follow into Array#each,
# Array#map and all those methods.

ok, then just modify those you want

eg,

class Array2 < Array
   %w([] first last).each do |m|
     define_method(m) do
        r = super
        puts "Here you go: #{r}"
        r
     end
   end
end
#=> ["[]", "first", "last"]
a=Array2.new [1,2,3]
#=> [1, 2, 3]
a[0]
Here you go: 1
#=> 1
a.first
Here you go: 1
#=> 1
a.size
#=> 3


 
# What I am still thinking about though, is this:
# Why on earth is Array#first not calling Array#[0] ???

that would be calling two methods, and would be quite expensive, right?

kind regards -botp