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comp.lang.ruby

confusion over 1.8.5 and 1.8.6 behavior of private

Kevin Barnes

9/14/2007 8:54:00 PM

I noticed some interesting behavior when implementing some
metaprogramming techniques with private. This is dependent on why's
metaid gem/library. I have included metaid at the end in case folks
are not familiar with it.

In 1.8.5 the output is:
true
true
true

In 1.8.6 the output is:
true
true
false

require 'metaid'

module NoSeeUm
def self.included(base)
base.extend(ClassMethods)
end
module ClassMethods
def see(name)
meta_eval do
define_method("#{name}_public") { puts "I'm public" }
define_method("#{name}_private") { puts "I'm private" }
private ("#{name}_private").to_sym
private
define_method("#{name}_maybe_private") { puts "I may be private" }
end
end

end
end

class Reveal
include NoSeeUm
see :me
end

p Reveal.public_methods.include?('me_public')
p Reveal.private_methods.include?('me_private')
p Reveal.private_methods.include?('me_maybe_private')

### Metaid ###

# Metaid == a few simple metaclass helper
# (See http://whytheluckystiff.net/articles/seeingMetaclassesCl....)
class Object
# The hidden singleton lurks behind everyone
def metaclass; class << self; self; end; end
def meta_eval &blk; metaclass.instance_eval &blk; end

# Adds methods to a metaclass
def meta_def name, &blk
meta_eval { define_method name, &blk }
end

# Defines an instance method within a class
def class_def name, &blk
class_eval { define_method name, &blk }
end
end

Just wondering why the me_maybe_private method doesn't show up in the
list of private methods in 1.8.6? Which version of Ruby is 'right'?

Thanks,
Kevin
1 Answer

Rick DeNatale

9/16/2007 9:07:00 PM

0

On 9/14/07, Kevin Barnes <vinbarnes@gmail.com> wrote:
> I noticed some interesting behavior when implementing some
> metaprogramming techniques with private. This is dependent on why's
> metaid gem/library. I have included metaid at the end in case folks
> are not familiar with it.
>
> In 1.8.5 the output is:
> true
> true
> true
>
> In 1.8.6 the output is:
> true
> true
> false

> Just wondering why the me_maybe_private method doesn't show up in the
> list of private methods in 1.8.6? Which version of Ruby is 'right'?
>


No idea which is right. I wasn't aware of a difference between 1.8.5 and 1.8.6.

This touches on something I blogged about not too long ago:

http://talklikeaduck.denh...articles/2007/09/04/block-you...


--
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denh...