From: ts <decoux@...>
Date: 2001-11-01T01:07:52+09:00
Subject: [ruby-talk:23973] Re: Overiding a method in another module

>>>>> "M" == Mark Hahn <mchahn@facelink.com> writes:

 Well, the response was given by another person, just a small precision

M> module M2
M>   class M1::C1      <=== gives syntax error

 This is in the ToDo

   * class Foo::Bar<Baz .. end, module Boo::Bar .. end

 but in your case, even if implemented, it will not work because it look at
 M2::M1::C1. You must, if one day it's implemented, write it as

   module M2
      class ::M1::C1 # shortly ::C1 in your case
      end
   end

 but I'm not really sure that it's a good idea to give the possibility to
 have ::Class. Any thought ?

pigeon% cat b.rb
#!./ruby
module M1
  class C1
    def meth
      p 'M1.meth'
    end
  end
end
include M1
C1.new.meth 

module M2
  class ::C1
    def meth
      p 'M2.meth'
    end
  end
end

C1.new.meth 
pigeon% 

pigeon% b.rb
"M1.meth"
"M2.meth"
pigeon% 

 There is also this in the ToDo

   * def Class#method .. end ??
   * def Foo::Bar::baz() .. end ??

 the first (Class#method) like class A::B, seems usefull and easy to
 implement. 

 I've found, but probably I'm wrong, that the second make the parser more
 complex and don't give something usefull. For example, if I'm right

   def Foo::Bar::baz()

 must be interpreted as

   module Foo
      def Bar::baz
      end
   end

 and this mean that this syntax is usefull only if the class Foo::Bar exist
 and I don't see any interest to have this syntax when it's possible to write

   class Foo::Bar
      def self.baz
      end
   end

 An example

pigeon% cat b.rb
#!./ruby -rii
dump
def A::B#method(a)
end

def A::C::method(b)
end
pigeon%

pigeon% b.rb
eval_tree
BLOCK
  NEWLINE <./b.rb:2>
  VCALL dump 
  NEWLINE <./b.rb:3>

  MODCLASS A
    SCOPE
      NEWLINE <./b.rb:3>

      MODCLASS B
        SCOPE
          NEWLINE <./b.rb:3>

          DEFN method 
            SCOPE
              ARGS(a)



  NEWLINE <./b.rb:6>

  MODCLASS A
    SCOPE
      NEWLINE <./b.rb:6>

      DEFS
        CONST C method 
        SCOPE
          ARGS(b)



./b.rb: uninitialized constant C at A (NameError)
pigeon% 

 What others think about these 2 syntax  (def Class#method(), def
 A::B::method()) ? Usefull or not ?



Guy Decoux