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# int_letter.hxx

    00001 // int_letter.hxx: this file is part of the Vaucanson project.
    00002 //
    00003 // Vaucanson, a generic library for finite state machines.
    00004 //
    00005 // Copyright (C) 2004, 2005, 2007, 2008, 2009 The Vaucanson Group.
    00006 //
    00007 // This program is free software; you can redistribute it and/or
    00008 // modify it under the terms of the GNU General Public License
    00009 // as published by the Free Software Foundation; either version 2
    00010 // of the License, or (at your option) any later version.
    00011 //
    00012 // The complete GNU General Public Licence Notice can be found as the
    00013 // `COPYING' file in the root directory.
    00014 //
    00015 // The Vaucanson Group consists of people listed in the `AUTHORS' file.
    00016 //
    00017 #ifndef VCSN_ALGEBRA_IMPLEMENTATION_LETTER_INT_LETTER_HXX
    00018 # define VCSN_ALGEBRA_IMPLEMENTATION_LETTER_INT_LETTER_HXX
    00019
    00020 # include <string>
    00021 # include <sstream>
    00022 # include <utility>
    00023 # include <climits>
    00024
    00025 # include <vaucanson/algebra/implementation/letter/int_letter.hh>
    00026
    00027 namespace vcsn
    00028 {
    00029   namespace algebra
    00030   {
    00031     template <>
    00032     struct letter_traits<int>
    00033     {
    00034       // This letter type needs more than one char to be displayed.
    00035       typedef misc::false_t is_char_letter;
    00036
    00037       enum
    00038       {
    00039         // Here we use UINT_MAX and not UINT_MAX + 1 because an enum cannot
    00040         // hold UINT_MAX + 1.
    00041         cardinal = UINT_MAX
    00042       };
    00043
    00044       // We can not "project" an int letter.
    00045       typedef undefined_type first_projection_t;
    00046       typedef undefined_type second_projection_t;
    00047
    00048       static
    00049       std::pair<bool, int>
    00050       literal_to_letter(const std::string& str)
    00051       {
    00052         std::stringstream sstr(str);
    00053
    00054         // Disallow a leading '+' because it would be too confusing:
    00055         // would '2+4' mean '2#+4' or '(2)+(4)'?
    00056         if (str[0] == '+')
    00057           return std::make_pair(false, 0);
    00058
    00059         int ret = 0;
    00060         // Do not skip spaces when translating numbers, otherwise a
    00061         // blank string such as " " would be translated into 0 without
    00062         // any problem.
    00063         sstr >> std::noskipws >> ret;
    00064
    00065         // Check if something is left in the stream.
    00066         if (!sstr.eof())
    00067           return std::make_pair(false, 0);
    00068
    00069         return std::make_pair(true, ret);
    00070       }
    00071
    00072       static
    00073       std::string
    00074       letter_to_literal(const int& c)
    00075       {
    00076         std::stringstream sstr;
    00077         sstr << c;
    00078         return sstr.str();
    00079       }
    00080
    00081       // An int is "simple" with dimension 1.
    00082       static std::string kind() { return "simple"; }
    00083       static int dim() { return 1; }
    00084
    00085     };
    00086
    00087   } // ! algebra
    00088
    00089 } // ! vcsn
    00090
    00091 #endif // ! VCSN_ALGEBRA_IMPLEMENTATION_LETTER_INT_LETTER_HXX