Pragmatic Forums | Posts in topic 'define_method in instance_eval'

define_method in instance_eval posted by khaled alhabache @ Fri, 26 Dec 2008 14:56:26 +0000

khaled alhabache — Fri, 26 Dec 2008 14:56:26 +0000

You can bypass that by defining the method to your singleton class
smthing like :

class Object

def singleton_class 
  class << self
    self 
  end 
end

end

class Foo
end

Foo.singleton_class.class_eval do define_method(:shout) do “shouting…” end
end

puts Foo.respond_to? :shout #true

define_method in instance_eval posted by James Whiteman @ Thu, 19 Jun 2008 16:09:13 +0000

James Whiteman — Thu, 19 Jun 2008 16:09:13 +0000

Thanks, Dave—fantastic series by the way.

define_method in instance_eval posted by Dave Thomas @ Thu, 19 Jun 2008 12:53:19 +0000

Dave Thomas — Thu, 19 Jun 2008 12:53:19 +0000

define_method always creates an instance method—now idea why, but it’s a deliberate decision of the implementers.

Dave

define_method in instance_eval posted by James Whiteman @ Wed, 18 Jun 2008 23:17:40 +0000

James Whiteman — Wed, 18 Jun 2008 23:17:40 +0000

Hello, all.

Does anyone have a good explanation for this?


class Foo
end

Foo.instance_eval do
  def jump
    "jumping..." 
  end

  define_method(:shout) do
    "shouting..." 
  end
end

Foo.respond_to? :jump
  => true
Foo.respond_to? :shout
  => false
Foo.new.respond_to? :shout
  => true

It seems that define_method is pushing the method ‘shout’ into Foo’s own m_tbl instead of in the metaclass.
This was a little unexpected to me.