From: Nathaniel Talbott <nathaniel@...>
Date: 2003-07-18T02:30:27+09:00
Subject: Re: What's the point?

Jim Freeze [mailto:jim@freeze.org] wrote:

> Hmm, I think 'x' has the same visibility as 'fred'.
> 
> irb
> irb(main):001:0> class C
> irb(main):002:1> def fred
> irb(main):003:2> def x
> irb(main):004:3> puts "x"
> irb(main):005:3> end
> irb(main):006:2> end
> irb(main):007:1> end
> => nil
> irb(main):008:0> c=C.new
> => #<C:0x183148>
> irb(main):009:0> c.fred
> => nil
> irb(main):010:0> c.x
> x

True, but it doesn't exist until fred is called:

  irb(main):001:0> class C
  irb(main):002:1> def fred
  irb(main):003:2> def x
  irb(main):004:3> puts "x"
  irb(main):005:3> end
  irb(main):006:2> end
  irb(main):007:1> end
  => nil
  irb(main):008:0> c = C.new
  => #<C:0x2b91d50>
  irb(main):009:0> c.x
  NoMethodError: undefined method `x' for #<C:0x2b91d50>
          from (irb):9
  irb(main):010:0> c.fred
  => nil
  irb(main):011:0> c.x
  x
  => nil

This means you could do something, er, interesting, like this:

  irb(main):001:0> class C
  irb(main):002:1> def initialize
  irb(main):003:2> def m
  irb(main):004:3> puts "m"
  irb(main):005:3> end
  irb(main):006:2> end
  irb(main):007:1> end
  => nil
  irb(main):008:0> C.instance_methods
  => []
  irb(main):009:0> c = C.new
  => #<C:0x2b8d610>
  irb(main):010:0> c.m
  m
  => nil

Why would you want to do that? I'm not exactly sure...


Nathaniel

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