option.hh

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// This file is part of Awali.
// Copyright 2016-2021 Sylvain Lombardy, Victor Marsault, Jacques Sakarovitch
//
// Awali is a 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 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
 
#ifndef AWALI_DYN_OPTIONS_OPTION_HH
#define AWALI_DYN_OPTIONS_OPTION_HH
 
#include <unordered_map>
#include <typeinfo>
 
#include <awali/dyn/core/any.hh>
#include <awali/common/priority.hh>
#include <awali/common/enums.hh>
#include <awali/common/enum_utils.hh>
#include <awali/common/demangle.hxx>
#include <awali/dyn/options/value.hh>
 
namespace awali {
  namespace dyn {
  namespace internal {
 
    template<typename T>
    struct acceptor_t {
      virtual bool is_valid(T const& value) {
        return true;
      }
      virtual std::string acceptable_values() {
        return ("any value of type "+awali::internal::demangle(typeid(T).name()));
      }
    };
 
    template<>
    struct acceptor_t<bool> {
      virtual bool is_valid(bool const& value) {
        return true;
      }
      std::string acceptable_values() {
        return ("boolean");
      }
    };
 
    template<>
    struct acceptor_t<std::string> {
      virtual bool is_valid(std::string const& value) {
        return true;
      }
      virtual std::string acceptable_values() {
        return ("any string");
      }
    };
 
    extern size_t next_id;
 
    template<typename T>
    class option_t {
     public:
      using value_t = T;
      const size_t id;
 
     private:
      std::string option_name;
      acceptor_t<value_t> acceptor;
      value_t default_value;
      bool default_set_by_user = false;
 
      option_t(option_t<T> other, value_t def) :
        id(other.id),
        option_name(other.option_name),
        acceptor(other.acceptor),
        default_value(other.default_set_by_user?other.def:def),
        default_set_by_user(other.was_user_set)
      {}
 
      template<typename X, typename P>
      internal::option_value_pair_t make(const X& value, priority::ONE<P>) {
        throw std::runtime_error("Wrong value type for option "+option_name
                                 + ". Expecting: "
                                 + acceptor.acceptable_values()
                                 + "." );
      }
 
      template<typename X=T, typename P>
      internal::option_value_pair_t
      make(const char* value, priority::TWO<P>)
      { return make(std::string(value), priority::value); }
 
      template<typename X=T, typename P>
      auto make(std::string const& value, priority::THREE<P>)
      -> decltype(
          awali::internal::make_enum<X>(value),
          internal::option_value_pair_t(id, default_value)
      ) {
        if (value == "default")
          return {id, default_value};
        return {id, awali::internal::make_enum<X>(value)};
      }
 
      template<typename P>
      internal::option_value_pair_t make(const T& value, priority::FOUR<P>) {
        if (!acceptor.is_valid(value))
          make(value, priority::one);
        return {id, value};
      }
 
 
 
     public:
      option_t(std::string name, T def, acceptor_t<T> acc = acceptor_t<T>())
        : id(internal::next_id++), option_name(name), acceptor(acc),
          default_value(def)
      {}
 
      bool acceptable(T value) {
        return acceptor(value);
      }
 
      operator internal::option_value_pair_t() {
        if (std::is_same<T, bool>::value)
          return {id, true};
        throw std::runtime_error("Using option without argument is only possible if they expect boolean values.");
      }
 
 
      option_t<value_t> with_default_value(value_t new_default_value) {
        return option_t(*this, new_default_value);
      }
 
 
      /* Globally sets the default value of this option.
       */
      void set_default_value(value_t new_default_value) {
        default_value = new_default_value;
        default_set_by_user = true;
      }
 
      value_t get_default_value() {
        return default_value;
      }
 
     public:
 
      template<typename X>
      internal::option_value_pair_t operator=(const X& value) {
        return make(value, priority::value);
      }
 
      value_t of_string(std::string str) {
        internal::option_value_pair_t pair = operator=(str);
        return (value_t) pair.value;
      }
 
    };
 
    } // end of namespace awali::dyn::internal
  } // end of namespace awali::dyn
} //end of namespace awali
 
 
#include<awali/dyn/options/declaration.incl.hh>
 
 
 
 
#endif