ChaiScript/include/chaiscript/dispatchkit/dynamic_object.hpp

// This file is distributed under the BSD License.
// See "license.txt" for details.
// Copyright 2009-2012, Jonathan Turner (jonathan@emptycrate.com)
// Copyright 2009-2014, Jason Turner (jason@emptycrate.com)
// http://www.chaiscript.com

#ifndef CHAISCRIPT_DYNAMIC_OBJECT_HPP_
#define CHAISCRIPT_DYNAMIC_OBJECT_HPP_

#include <cassert>
#include <map>
#include <memory>
#include <string>
#include <typeinfo>
#include <utility>
#include <vector>

#include "../chaiscript_defines.hpp"
#include "boxed_cast.hpp"
#include "boxed_cast_helper.hpp"
#include "boxed_value.hpp"
#include "proxy_functions.hpp"
#include "type_info.hpp"

namespace chaiscript {
class Type_Conversions;
namespace dispatch {
class Proxy_Function_Base;
}  // namespace dispatch
}  // namespace chaiscript

namespace chaiscript
{
  namespace dispatch
  {
    class Dynamic_Object
    {
      public:
        Dynamic_Object(std::string t_type_name)
          : m_type_name(std::move(t_type_name))
        {
        }

        std::string get_type_name() const
        {
          return m_type_name;
        }

        Boxed_Value get_attr(const std::string &t_attr_name)
        {
          return m_attrs[t_attr_name];
        }

        std::map<std::string, Boxed_Value> get_attrs() const
        {
          return m_attrs;
        }

      private:
        std::string m_type_name;

        std::map<std::string, Boxed_Value> m_attrs;
    };

    namespace detail
    {
      /// A Proxy_Function implementation designed for calling a function
      /// that is automatically guarded based on the first param based on the
      /// param's type name
      class Dynamic_Object_Function : public Proxy_Function_Base
      {
        public:
          Dynamic_Object_Function(
              std::string t_type_name,
              const Proxy_Function &t_func)
            : Proxy_Function_Base(t_func->get_param_types()),
            m_type_name(std::move(t_type_name)), m_func(t_func), m_doti(user_type<Dynamic_Object>())
          {
            assert( (t_func->get_arity() > 0 || t_func->get_arity() < 0)
                && "Programming error, Dynamic_Object_Function must have at least one parameter (this)");
          }

          Dynamic_Object_Function(
              std::string t_type_name,
              const Proxy_Function &t_func,
              const Type_Info &t_ti)
            : Proxy_Function_Base(build_param_types(t_func->get_param_types(), t_ti)),
              m_type_name(std::move(t_type_name)), m_func(t_func), m_ti(new Type_Info(t_ti)), m_doti(user_type<Dynamic_Object>())
          {
            assert( (t_func->get_arity() > 0 || t_func->get_arity() < 0)
                && "Programming error, Dynamic_Object_Function must have at least one parameter (this)");
          }

          virtual ~Dynamic_Object_Function() {}

          Dynamic_Object_Function &operator=(const Dynamic_Object_Function) = delete;
          Dynamic_Object_Function(Dynamic_Object_Function &) = delete;

          virtual bool operator==(const Proxy_Function_Base &f) const CHAISCRIPT_OVERRIDE
          {
            if (const auto *df = dynamic_cast<const Dynamic_Object_Function *>(&f))
            {
              return df->m_type_name == m_type_name && (*df->m_func) == (*m_func);
            } else {
              return false;
            }
          }

          virtual bool call_match(const std::vector<Boxed_Value> &vals, const Type_Conversions &t_conversions) const CHAISCRIPT_OVERRIDE
          {
            if (dynamic_object_typename_match(vals, m_type_name, m_ti, t_conversions))
            {
              return m_func->call_match(vals, t_conversions);
            } else {
              return false;
            }
          }    

          virtual std::vector<Const_Proxy_Function> get_contained_functions() const CHAISCRIPT_OVERRIDE
          {
            return {m_func};
          }


          virtual int get_arity() const CHAISCRIPT_OVERRIDE
          {
            return m_func->get_arity();
          }

          virtual std::string annotation() const CHAISCRIPT_OVERRIDE
          {
            return m_func->annotation();
          }


        protected:
          virtual Boxed_Value do_call(const std::vector<Boxed_Value> &params, const Type_Conversions &t_conversions) const CHAISCRIPT_OVERRIDE
          {
            if (dynamic_object_typename_match(params, m_type_name, m_ti, t_conversions))
            {
              return (*m_func)(params, t_conversions);
            } else {
              throw exception::guard_error();
            } 
          }

          virtual bool compare_first_type(const Boxed_Value &bv, const Type_Conversions &t_conversions) const CHAISCRIPT_OVERRIDE
          {
            return dynamic_object_typename_match(bv, m_type_name, m_ti, t_conversions);
          }

        private:
          static std::vector<Type_Info> build_param_types(
              const std::vector<Type_Info> &t_inner_types, const Type_Info& t_objectti)
          {
            std::vector<Type_Info> types(t_inner_types);

            assert(types.size() > 1);
            assert(types[1].bare_equal(user_type<Boxed_Value>()));
            types[1] = t_objectti;
            return types;
          }

          bool dynamic_object_typename_match(const Boxed_Value &bv, const std::string &name,
              const std::unique_ptr<Type_Info> &ti, const Type_Conversions &t_conversions) const
          {
            if (bv.get_type_info().bare_equal(m_doti))
            {
              try {
                const Dynamic_Object &d = boxed_cast<const Dynamic_Object &>(bv, &t_conversions);
                return name == "Dynamic_Object" || d.get_type_name() == name;
              } catch (const std::bad_cast &) {
                return false;
              } 
            } else {
              if (ti)
              {
                return bv.get_type_info().bare_equal(*ti);
              } else {
                return false;
              }
            }

          }

          bool dynamic_object_typename_match(const std::vector<Boxed_Value> &bvs, const std::string &name,
              const std::unique_ptr<Type_Info> &ti, const Type_Conversions &t_conversions) const
          {
            if (bvs.size() > 0)
            {
              return dynamic_object_typename_match(bvs[0], name, ti, t_conversions);
            } else {
              return false;
            }
          }

          std::string m_type_name;
          Proxy_Function m_func;
          std::unique_ptr<Type_Info> m_ti;
          const Type_Info m_doti;


      };


      /**
       * A Proxy_Function implementation designed for creating a new
       * Dynamic_Object
       * that is automatically guarded based on the first param based on the
       * param's type name
       */
      class Dynamic_Object_Constructor : public Proxy_Function_Base
      {
        public:
          Dynamic_Object_Constructor(
              std::string t_type_name,
              const Proxy_Function &t_func)
            : Proxy_Function_Base(build_type_list(t_func->get_param_types())),
              m_type_name(std::move(t_type_name)), m_func(t_func)
          {
            assert( (t_func->get_arity() > 0 || t_func->get_arity() < 0)
                && "Programming error, Dynamic_Object_Function must have at least one parameter (this)");
          }

          static std::vector<Type_Info> build_type_list(const std::vector<Type_Info> &tl)
          {
            auto begin = tl.begin();
            auto end = tl.end();

            if (begin != end)
            {
              ++begin;
            }

            return std::vector<Type_Info>(begin, end);
          }

          virtual ~Dynamic_Object_Constructor() {}

          virtual bool operator==(const Proxy_Function_Base &f) const CHAISCRIPT_OVERRIDE
          {
            const Dynamic_Object_Constructor *dc = dynamic_cast<const Dynamic_Object_Constructor*>(&f);
            if (dc)
            {
              return dc->m_type_name == m_type_name && (*dc->m_func) == (*m_func);
            } else {
              return false;
            }
          }

          virtual bool call_match(const std::vector<Boxed_Value> &vals, const Type_Conversions &t_conversions) const CHAISCRIPT_OVERRIDE
          {
            std::vector<Boxed_Value> new_vals{Boxed_Value(Dynamic_Object(m_type_name))};
            new_vals.insert(new_vals.end(), vals.begin(), vals.end());

            return m_func->call_match(new_vals, t_conversions);
          }    


          virtual int get_arity() const CHAISCRIPT_OVERRIDE
          {
            // "this" is not considered part of the arity
            return m_func->get_arity() - 1; 
          }

          virtual std::string annotation() const CHAISCRIPT_OVERRIDE
          {
            return m_func->annotation();
          }

        protected:
          virtual Boxed_Value do_call(const std::vector<Boxed_Value> &params, const Type_Conversions &t_conversions) const CHAISCRIPT_OVERRIDE
          {
            auto bv = var(Dynamic_Object(m_type_name));
            std::vector<Boxed_Value> new_params{bv};
            new_params.insert(new_params.end(), params.begin(), params.end());

            (*m_func)(new_params, t_conversions);

            return bv;
          }

        private:
          std::string m_type_name;
          Proxy_Function m_func;

      };
    }
  }
}
#endif