builder.h

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// Author(s): Wieger Wesselink
// Copyright: see the accompanying file COPYING or copy at
// https://github.com/mCRL2org/mCRL2/blob/master/COPYING
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
/// \file mcrl2/core/builder.h
/// \brief add your file description here.
 
#ifndef MCRL2_CORE_BUILDER_H
#define MCRL2_CORE_BUILDER_H
 
#include "mcrl2/atermpp/aterm_list.h"
 
namespace mcrl2
{
 
namespace core
{
 
#ifdef MCRL2_DEBUG_EXPRESSION_BUILDER
inline void msg(const std::string& s)
{
  std::cout << "--- " << s << " ---" << std::endl;
}
#else
inline void msg(const std::string&)
{}
#endif
 
/**
 * \brief expression builder that visits all sub expressions
 *
 * Types:
 *  \arg Derived the type of a derived class, as per CRTP
 *
 **/
template <typename Derived>
struct builder
{
  // Enter object
  template <typename T>
  void enter(const T&)
  {}
 
  // Leave object
  template <typename T>
  void leave(const T&)
  {}
 
  template <typename T>
  void update(T& x, typename atermpp::disable_if_container<T>::type* = nullptr)
  {
    msg("non-container visit");
    T result;
    static_cast<Derived*>(this)->apply(result, x);
    x = result;
  }
 
  // container visit
  template <typename T>
  void update(T& x, typename atermpp::enable_if_container<T>::type* = nullptr)
  {
    msg("container visit");
    for (auto& v: x)
    {
      static_cast<Derived*>(this)->update(v);
    }
  }
 
  // aterm set visit
  template <typename T>
  void update(std::set<T>& x)
  {
    msg("set visit");
    std::set<T> result;
    for (T v: x)
    {
      static_cast<Derived*>(this)->update(v);
      result.insert(v);
    }
    result.swap(x);
  }
 
  // term_list visit copy
  template <typename T, typename U>
  void apply(atermpp::term_list<T>& result, const atermpp::term_list<U>& x)
  {
    msg("term_list traversal");
    atermpp::make_term_list<T>(static_cast<atermpp::term_list<T>&>(result),
                               x.begin(),
                               x.end(),
                               [&](T& result, const U& v) { static_cast<Derived*>(this)->apply(result, v); } );
  }
};
 
 
// apply a builder without additional template arguments
template <template <class> class Builder>
class apply_builder: public Builder<apply_builder<Builder> >
{
  typedef Builder<apply_builder<Builder> > super;
 
  public:
 
    using super::enter;
    using super::leave;
    using super::apply;
    using super::update;
};
 
template <template <class> class Builder>
apply_builder<Builder>
make_apply_builder()
{
  return apply_builder<Builder>();
}
 
// apply a builder with one additional template argument
template <template <class> class Builder, class Arg1>
class apply_builder_arg1: public Builder<apply_builder_arg1<Builder, Arg1> >
{
  typedef Builder<apply_builder_arg1<Builder, Arg1> > super;
 
  public:
    using super::enter;
    using super::leave;
    using super::apply;
    using super::update;
 
    apply_builder_arg1(const Arg1& arg1):
      super(arg1)
    {}
};
 
template <template <class> class Builder, class Arg1>
apply_builder_arg1<Builder, Arg1>
make_apply_builder_arg1(const Arg1& arg1)
{
  return apply_builder_arg1<Builder, Arg1>(arg1);
}
 
// apply a builder with two additional template arguments
template <template <class> class Builder, class Arg1, class Arg2>
class apply_builder_arg2: public Builder<apply_builder_arg2<Builder, Arg1, Arg2> >
{
  typedef Builder<apply_builder_arg2<Builder, Arg1, Arg2> > super;
 
  public:
    using super::enter;
    using super::leave;
    using super::apply;
    using super::update;
 
    apply_builder_arg2(const Arg1& arg1, const Arg2& arg2):
      super(arg1, arg2)
    {}
};
 
template <template <class> class Builder, class Arg1, class Arg2>
apply_builder_arg2<Builder, Arg1, Arg2>
make_apply_builder_arg2(const Arg1& arg1, const Arg2& arg2)
{
  return apply_builder_arg2<Builder, Arg1, Arg2>(arg1, arg2);
}
 
 
// apply a builder without additional template arguments
template <template <class> class Builder, class Function>
struct update_apply_builder: public Builder<update_apply_builder<Builder, Function> >
{
  typedef Builder<update_apply_builder<Builder, Function> > super;
 
  using super::enter;
  using super::leave;
  using super::apply;
  using super::update;
 
  using argument_type = typename Function::argument_type; ///< The argument_type is required to restrict the overloads of apply(x) to that type.
  using result_type = typename Function::result_type; ///< The argument_type is required to restrict the overloads of apply(x) to that type.
  const Function& f_;
 
  template <class T>
  void apply(T& result, const argument_type& x) // -> decltype(f_(x))
  {
    // static_cast<result_type&>(result) = f_(x);
    result = static_cast<T>(f_(x));
  }
 
  update_apply_builder(const Function& f)
    : f_(f)
  {}
};
 
template <template <class> class Builder, class Function>
update_apply_builder<Builder, Function>
make_update_apply_builder(const Function& f)
{
  return update_apply_builder<Builder, Function>(f);
}
 
// apply a builder with one additional template argument
template <template <class> class Builder, class Function, class Arg1>
class update_apply_builder_arg1: public Builder<update_apply_builder_arg1<Builder, Function, Arg1> >
{
  typedef Builder<update_apply_builder_arg1<Builder, Function, Arg1> > super;
 
  using super::enter;
  using super::leave;
  using super::apply;
  using super::update;
 
  using argument_type = typename Function::argument_type; ///< The argument_type is required to restrict the overloads of apply(x) to that type.
  using result_type = typename Function::result_type;
  const Function& f_;
 
  template <class T>
  void apply(T& result, const argument_type& x) // -> decltype(f_(x))
  {
    result = f_(x);
  }
 
  update_apply_builder_arg1(const Function& f, const Arg1& arg1):
    super(arg1),
    f_(f)
  {}
};
 
template <template <class> class Builder, class Function, class Arg1>
update_apply_builder_arg1<Builder, Function, Arg1>
make_update_apply_builder_arg1(const Function& f)
{
  return update_apply_builder_arg1<Builder, Function, Arg1>(f);
}
 
} // namespace core
 
} // namespace mcrl2
 
#endif // MCRL2_CORE_BUILDER_H