From: transfire@...
Date: 2006-07-11T05:35:59+09:00
Subject: Re: instance_exec


Mauricio Fernandez wrote:
> Here's an improved (hastily written, not thoroughly tested) version:

Okay, I took your draft and worked on it some more and came up with the
following, but there's something very strange....

require 'thread'

class Object
  module  TemporaryMethods; end
  include TemporaryMethods
end

class Proc

  # Creates a local method based on a Proc.
  def to_method(name=nil, recv=nil)
    recv ||= eval("self", self)
    klass = name ? recv.class : TemporaryMethods
    begin
      old, Thread.critical = Thread.critical, true
      unless name
        n = 0
        n += 1 while klass.method_defined?(name = "__to_method_#{n}")
        #n += 1 while recv.respond_to?(name = "__to_method_#{n}")
      end
      me = self
      klass.module_eval{ define_method(name, &me) }
      recv.method(name) #if klass == TemporaryMethods
    ensure
      if klass == TemporaryMethods
        klass.module_eval{ remove_method(name) } #rescue nil }
        #klass.module_eval{ undef_method(name) } #rescue nil }
      end
      Thread.critical = old
    end
  end

end


Notice the two remarks on n+=1... and klass.module_eval...., if you
unremark the first one, the one with recv.respond_to? it doesn't alwasy
see that the method has been removed -- I have to idea why that is
since it certainly has been. If you use undef_method instead of
remove_method, it work again though! That really blows my min b/c I
though undef_method didn;t actually remove the method. So I'm really
confused about that. Here's the test I use for the Symbols:

# This is dependent on other tests! Be aware!

    def test_memory
      a = 2
      tproc = proc { |x| x + a }
      100.times {
        tmethod = tproc.to_method
        assert_equal( 3, tmethod.call(1) )
      }
      meths = Symbol.all_symbols.select { |s| s.to_s =~ /^__to_method/
}
      assert_equal( 1, meths.size )
    end

Also is the 'resuce nil' really needed?

T.

P.S. Is there any reason you use module_eval { define_method...  rather
then send(:defined_method?...