instance_exec (Kernel)

    # File lib/templater/core_ext/kernel.rb, line 3
        def instance_exec(*args, &block)
          mname = "__instance_exec_#{Thread.current.object_id.abs}_#{object_id.abs}"
          Object.class_eval{ define_method(mname, &block) }
          begin
            ret = send(mname, *args)
          ensure
            Object.class_eval{ undef_method(mname) } rescue nil
          end
          ret
        end