スコープとクラスメソッドの疑問

メタプログラミングRubyでフラットスコープについて学んだ。
でもこれから一つの疑問が生じた。



  1 my_var = 1  2 puts "myvar:#{my_var} was called at the top level"  3 

  4 MyClass = Class.new do

  5   my_var += 1

  6   puts "myvar:#{my_var} was called at the class"

  7 

  8   define_method :my_method do

  9     my_var += 1

 10     puts "myvar:#{my_var} was called at the method"

 11   end

 12 end

 13 

 14 my = MyClass.new

 15 my.my_method

 16 

 17 puts "------------"

 18 

 19 @@my_var = 1

 20 puts "myvar:#{@@my_var} was called at the top level"

 21 class MyClass2 

 22   @@my_var += 1

 23   puts "myvar:#{@@my_var} was called at the class"

 24   

 25   def my_method 

 26     @@my_var += 1

 27     puts "myvar:#{@@my_var} was called at the method"

 28   end

 29 

 30 end

 31 

 32 my2 = MyClass2.new

 33 my2.my_method

この二つのコードは同じ出力をする。



  1 myvar:1 was called at the top level

  2 myvar:2 was called at the class

  3 myvar:3 was called at the method

  4 ------------

  5 myvar:1 was called at the top level

  6 myvar:2 was called at the class

  7 myvar:3 was called at the method

違いはなんだろうなぁ。