From: "juan pedro meriño" <juapdiaz@...>
Date: 2007-06-22T05:33:35+09:00
Subject: Re: How do I intercept creation of fundatmental types, eg. []

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How i use pointer in ruby?

2007/6/21, Durant S. <mobiledurant@yahoo.com>:
>
>
> Hi,
>
> I'm new to ruby and I love the introspection and metaprogramming
> capabilities. However, I'm having a problem. I want to count the number
> of arrays created. I can only intercept and redefine explicit calls to
> Array.new
>
> For example, I can catch this:
>
> b =3D Array.new
>
> but I cannot catch this:
>
> x =3D [3,4,5]
>
> It seems like I should be able to do it with the awesome power of ruby
> :), but I can't figure out how.
>
>
> Here is a simple program I am using to try to intercept the creation of
> Array (I've tried catching "[]", initialize, new and clone - I also
> tried overriding Object.new, but couldn't get that to work either, but
> that code is not included). You'll notice little newbie commented
> questions sprinkled in the code.
>
> The count variable should be 4 because I make 4 arrays. How do I get
> that?
>
> Thanks in advance!
>
>
>
> #! /usr/bin/env ruby
>
> class Array
>
>   @@count =3D 0
>
>   # How do I alias Array.new?
>   # alias orig_new method('Array.new')
>
>   # this doesn't work either
>   # orig_new =3D method('Array.new')
>
>   def Array.new(*args,&block)
>     print "In Array.new"
>     print " with #{args.inspect}" if args
>     print " and #{block.inspect}" if block
>     print "\n"
>     print "\tself.class is #{self.class}\n"
>     @@count +=3D 1
>     puts "\tcount is now #{@@count}"
>     #orig_new
>     # Is this right?
>     super
>   end
>
> # this alias does not work
> # how do refer to this method "[]"?
> #   alias orig_ob_cb method('[]')
> #   def [](*args, &block)
> #     puts "In [] ... We never seem to get here."
> #     # this is probably the method for elem =3D array[]
> #     # a right hand side assignment
> #     orig_ob_cb(*args, &block)
> #   end
>
>   alias orig_clone clone
>   def clone
>     puts "In clone ... Nope we're not cloning."
>     orig_clone
>   end
>
>   alias orig_initialize initialize
>   def initialize(*args, &block)
>     puts "An Array was just initialized!"
>     orig_initialize(*args, &block)
>   end
>
>   def count
>     @@count
>   end
> end
>
> x =3D [3,4,5]
> puts "x.class is #{x.class}"
> # notice we have the count attribute, but we never called new
> puts "count is #{x.count}"
> puts "x is #{x.inspect}"
>
> puts ""
> a =3D Array.new 2, :a
> puts "a.class is #{a.class}"
> puts "count is #{a.count}"
> a << 7
> puts "a is #{a.inspect}"
>
> puts ""
> b =3D Array.new 3,3
> puts "b.class is #{b.class}"
> puts "count is #{b.count}"
> b[0] =3D 7
> puts "b is #{b.inspect}"
> puts "b[0] is #{b[0]}"
>
> puts ""
> c =3D []
> puts "c.class is #{c.class}"
> puts "count is #{c.count}"
> puts "c is #{c.inspect}"
>
> --
> Posted via http://www.ruby-forum.com/.
>
>


--=20
Juan Pedro Meri=F1o Diaz
Ing de Sistema CURN

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