I don't know why!!

[Kyung won Cheon]

-- test1.rb --

module M
module MM
class C
end

class D < MM::C
end

class E < MM::C; puts self; end
end
end

# => M::MM::E

-- test2.rb --

module M
module MM
class C
end

class D < MM::C
end

#class E < MM::C; puts self; end
end
end

M::MM.module_eval("class E < MM::C; puts self; end")

# => uninitialized constant M::MM::MM (NameError)

-- test3.rb --

module M
module MM
class C
end

class D < MM::C
end

#class E < MM::C; puts self; end
end
end

M::MM.module_eval("class E < C; puts self; end")

# => M::MM::E

###################
# test2.rb ???
###################

 

[TPReal]

-- test1.rb --

module M
  module MM
    class C
    end

    class D < MM::C
    end

    class E < MM::C; puts self; end
  end
end

# => M::MM::E

-- test2.rb --

module M
  module MM
    class C
    end

    class D < MM::C
    end

    #class E < MM::C; puts self; end
  end
end

M::MM.module_eval("class E < MM::C; puts self; end")

# => uninitialized constant M::MM::MM (NameError)

-- test3.rb --

module M
  module MM
    class C
    end

    class D < MM::C
    end

    #class E < MM::C; puts self; end
  end
end

M::MM.module_eval("class E < C; puts self; end")

# => M::MM::E

###################
# test2.rb ???
###################

Well, it's simple, if you say MM::C inside an M::MM's module_eval,
then it means M::MM::MM::C, and this is undefined. When you say Temp
\dir from inside C:\Temp, then it means C:\Temp\Temp\dir.