Line data    Source code

       1             : // Author(s): Jan Friso Groote
       2             : // Copyright: see the accompanying file COPYING or copy at
       3             : // https://github.com/mCRL2org/mCRL2/blob/master/COPYING
       4             : //
       5             : // Distributed under the Boost Software License, Version 1.0.
       6             : // (See accompanying file LICENSE_1_0.txt or copy at
       7             : // http://www.boost.org/LICENSE_1_0.txt)
       8             : //
       9             : 
      10             : /** \file state_label_empty.h
      11             :  *
      12             :  * \brief This file contains the class with empty state labels.
      13             :  * \author Jan Friso Groote
      14             :  */
      15             : 
      16             : 
      17             : #ifndef MCRL2_LTS_STATE_LABEL_EMPTY_H
      18             : #define MCRL2_LTS_STATE_LABEL_EMPTY_H
      19             : 
      20             : #include <string>
      21             : 
      22             : namespace mcrl2
      23             : {
      24             : namespace lts
      25             : {
      26             : 
      27             : /** \brief Contains empty state values, used for lts's without state valued.
      28             :  *  \details Empty state values are used in labelled transition
      29             :  *          systems which do not have state values, such as
      30             :  *          the .aut format. */
      31             : class state_label_empty
      32             : {
      33             :   public:
      34             : 
      35             :     /* \brief Equality on empty state labels. Always returns true.
      36             :     */
      37          80 :     bool operator ==(const state_label_empty&) const
      38             :     {
      39          80 :       return true;
      40             :     }
      41             : 
      42             :     /* \brief Non equality on empty state labels. Always returns false.
      43             :     */
      44          80 :     bool operator !=(const state_label_empty& other) const
      45             :     {
      46          80 :       return !(*this==other);
      47             :     }
      48             : 
      49             :     /** \brief An operator to concatenate two state labels. */
      50        2040 :     state_label_empty operator+(const state_label_empty& ) const
      51             :     {
      52        2040 :       return state_label_empty();
      53             :     }
      54             : 
      55             : };
      56             : 
      57             : inline std::string pp(const state_label_empty& )
      58             : {
      59             :   return "empty";
      60             : }
      61             : 
      62             : 
      63             : } // namespace lts
      64             : } // namespace mcrl2
      65             : 
      66             : #endif
      67             : 
      68             :