krat_exp_support.hxx

// krat_exp_support.hxx: this file is part of the Vaucanson project.
//
// Vaucanson, a generic library for finite state machines.
//
// Copyright (C) 2001, 2002, 2003, 2004 The Vaucanson Group.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// The complete GNU General Public Licence Notice can be found as the
// `COPYING' file in the root directory.
//
// The Vaucanson Group consists of people listed in the `AUTHORS' file.
//
#ifndef VCSN_ALGEBRA_IMPLEMENTATION_SERIES_KRAT_EXP_SUPPORT_HXX
# define VCSN_ALGEBRA_IMPLEMENTATION_SERIES_KRAT_EXP_SUPPORT_HXX

# include <utility>
# include <vaucanson/algebra/implementation/series/krat_exp_pattern.hh>
# include <vaucanson/algebra/implementation/series/krat_exp_is_finite_app.hxx>

namespace vcsn {

  template <class Series, class T, class Dispatch>
  class SupportMatcher : public algebra::KRatExpMatcher<
    SupportMatcher<Series, T, Dispatch>,
    T,
    int,
    Dispatch
    >
  {
  public:
    typedef IsFiniteAppMatcher<Series, T, Dispatch>     self_t;
    typedef int                                         return_type;
    typedef Series                                      series_set_t;
    typedef Element<Series, T>                          series_set_elt_t;
    typedef typename series_set_elt_t::monoid_elt_t             monoid_elt_t;
    typedef typename monoid_elt_t::value_t              monoid_elt_value_t;
    typedef typename series_set_elt_t::semiring_elt_t   semiring_elt_t;
    typedef typename semiring_elt_t::value_t            semiring_elt_value_t;
    typedef std::list<monoid_elt_value_t>                       support_t;
    typedef std::list<std::pair<semiring_elt_value_t, monoid_elt_value_t> >
                                                        ext_support_t;
    INHERIT_CONSTRUCTORS(self_t, T, return_type, Dispatch);

    SupportMatcher(const series_set_t& s):
      series_(s)
    {}

    MATCH__(Product, lhs, rhs)
    {
      ext_support_t old_supp_ = supp_;
      supp_.clear();
      match(lhs);
      ext_support_t lhs_s = supp_;
      supp_.clear();
      match(rhs);
      ext_support_t ret;
      for_each_const_(ext_support_t, c, lhs_s)
        for_each_const_(ext_support_t, d, supp_)
        {
          monoid_elt_t mc(series_.monoid(), c->second);
          monoid_elt_t md(series_.monoid(), d->second);
          semiring_elt_t wc(series_.semiring(), c->first);
          semiring_elt_t wd(series_.semiring(), d->first);
          ret.push_back(std::make_pair((wc * wd).value(),
                                       (mc * md).value()));
        }
      supp_ = ret;
      supp_.insert(supp_.begin(), old_supp_.begin(), old_supp_.end());
      return 0;
    }
    END

    MATCH__(Sum, lhs, rhs)
    {
      match(lhs);
      match(rhs);
      return 0;
    }
    END

    MATCH_(Star, node)
    {
      result_not_computable("undefined case (star) in krat_exp_support");
      return 0;
    }
    END

    MATCH__(LeftWeight, w, node)
    {
      ext_support_t old_supp_ = supp_;
      supp_.clear();
      match(node);
      for_each_(ext_support_t, c, supp_)
        c->first = op_mul(series_.semiring(), w, c->first);
      supp_.insert(supp_.begin(), old_supp_.begin(), old_supp_.end());
      return 0;
    }
    END

    MATCH__(RightWeight, node, w)
    {
      ext_support_t old_supp_ = supp_;
      supp_.clear();
      match(node);
      for_each_(ext_support_t, c, supp_)
        c->first = op_mul(series_.semiring(), c->first, w);
      supp_.insert(supp_.begin(), old_supp_.begin(), old_supp_.end());
      return 0;
    }
    END

    MATCH_(Constant, m)
    {
      supp_.push_back(std::make_pair
                      (identity_value(series_.semiring(),
                                      SELECT(semiring_elt_value_t)),
                       m));
      return 0;
    }
    END

    MATCH(Zero)
    {
      return 0;
    }
    END

    MATCH(One)
    {
      supp_.push_back(std::make_pair
                      (identity_value(series_.semiring(),
                                      SELECT(semiring_elt_value_t)),
                       identity_value(series_.monoid(),
                                      SELECT(monoid_elt_value_t))));
      return 0;
    }
    END

    support_t get()
    {
      support_t ret;
      ext_support_t s = ext_get();
      for_each_const_(ext_support_t, c, s)
        ret.push_back(c->second);
      return ret;
    }

    ext_support_t& ext_get()
    {
      // Now join same words.
      typedef std::map<monoid_elt_value_t, semiring_elt_value_t> tmap_t;
      tmap_t v;
      typename tmap_t::iterator f;
      for_each_const_(ext_support_t, c, supp_)
        {
          if ((f = v.find(c->second)) == v.end())
            v[c->second] = c->first;
          else
            v[c->second] = op_add(series_.semiring(), v[c->second], c->first);
        }
      supp_.clear();
      for_each_const_(tmap_t, m, v)
        supp_.push_back(std::make_pair(m->second, m->first));
      return supp_;
    }

  private:
    ext_support_t               supp_;
    const series_set_t&         series_;
  };

} // vcsn

#endif // ! VCSN_ALGEBRA_IMPLEMENTATION_SERIES_KRAT_EXP_SUPPORT_HXX

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