--- remove_instance_variable(name)

    ֥Ȥ饤󥹥ѿ name Υ
    ѿꤵƤ֤ͤޤname  Symbol 
    ʸǤ

    ֥Ȥ󥹥ѿ name ʤ㳰 
    NameError ȯޤ

        class Foo
          def foo
            @foo = 1
            p remove_instance_variable :@foo # => 1
            p remove_instance_variable :@foo # => instance variable @foo not defined (NameError)
          end
        end
        Foo.new.foo

    Module#remove_class_variable [Module/remove_class_variable],
    Module#remove_const [Module/remove_const] 
    ⻲ȤƤ

