>>>>> "A" == Arnaud Bergeron <abergeron / gmail.com> writes:

A> No.  In case of instance_eval you will be in the class, and in the
A> case of (class|module)_eval you will be in the class of the class
A> (which is Class) [Hurray for multiple meanings to a word!]

 no, not really. ruby use self and internally ruby_class which give it
 where it can define method when it find keyword like 'def', 'alias', ...

 With obj.instance_eval ruby will make
   * self = obj , ruby_class = obj singleton class

 This mean that inside instance_eval it will define singleton method

 #instance_eval work with any object, but a class is a little special
 because it can be seen as an object or as a class. This is why
 #module_eval, #class_eval exist.

 With obj.class_eval ruby will make

  * self = obj, ruby_class = obj

 This mean that inside class_eval ruby will define instance method.

 One way to see it

moulon% ruby -e 'class A; end; A.instance_eval{ p self; def a() puts "A::a" end}; A.a'
A
A::a
moulon%
 
moulon% ruby -e 'class A; end; A.class_eval{ p self; def a() puts "A#a" end}; A.new.a'
A
A#a
moulon% 



Guy Decoux