automaton.hh

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#pragma once

#include <algorithm> // move
#include <memory> // shared_ptr

#include <vcsn/core/automaton.hh> // Automaton
#include <vcsn/dyn/cast.hh>
#include <vcsn/dyn/fwd.hh>
#include <vcsn/misc/export.hh>
#include <vcsn/misc/symbol.hh>

namespace vcsn
{
  namespace dyn
  {
    namespace detail
    {
      class LIBVCSN_API automaton
      {
      public:
        automaton(std::nullptr_t ptr)
          : self_(ptr)
        {}

        template <typename AutImpl>
        automaton(const std::shared_ptr<AutImpl>& aut)
          : self_(std::make_shared<model<std::shared_ptr<AutImpl>>>(aut))
        {}

        symbol vname() const
        {
          return self_->vname();
        }

        template <Automaton Aut>
        auto& as()
        {
          return dyn_cast<model<Aut>&>(*self_).automaton();
        }

        template <Automaton Aut>
        const auto& as() const
        {
          return dyn_cast<const model<Aut>&>(*self_).automaton();
        }

        auto* operator->()
        {
          return this;
        }

        const auto* operator->() const
        {
          return this;
        }

        bool operator!() const
        {
          return !self_;
        }

      private:
        struct base
        {
          virtual ~base() = default;
          virtual symbol vname() const = 0;
        };

        template <Automaton Aut>
        struct model final : base
        {
          using automaton_t = Aut;

          model(automaton_t aut)
            : automaton_(std::move(aut))
          {}

          symbol vname() const
          {
            return automaton()->sname();
          }

          auto& automaton()
          {
            return automaton_;
          }

          const auto& automaton() const
          {
            return automaton_;
          }

          automaton_t automaton_;
        };

        std::shared_ptr<base> self_;
      };
    }

    using automaton = detail::automaton;

    template <Automaton Aut>
    automaton
    make_automaton(const Aut& aut)
    {
      return automaton(aut);
    }
  }
}