# File lib/ruote/exp/ro_variables.rb, line 141
    def un_set_variable (op, var, val, should_persist)

      if op == :set
        Ruote.set(h.variables, var, val)
      else # op == :unset
        Ruote.unset(h.variables, var)
      end

      return unless should_persist

      if r = try_persist # persist failed, have to retry

        @h = r
        un_set_variable(op, var, val, true)

      else # success

        @context.storage.put_msg("variable_#{op}", 'var' => var, 'fei' => h.fei)
      end
    end