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feat: toml::visit takes multiple values
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@ToruNiina
ToruNiina committed Jan 12, 2025
1 parent 0f6e08f commit 04c55d0
Showing 1 changed file with 94 additions and 39 deletions.
133 changes: 94 additions & 39 deletions include/toml11/visit.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8,74 +8,129 @@
namespace toml
{

template<typename Visitor, typename TC>
cxx::return_type_of_t<Visitor, const typename basic_value<TC>::boolean_type&>
visit(Visitor&& visitor, const basic_value<TC>& v)
namespace detail
{

template<typename F, typename ... Ts>
using visit_result_t = decltype(std::declval<F>()(std::declval<Ts>().as_boolean() ...));

template<typename F, typename T>
struct front_binder
{
template<typename ... Args>
auto operator()(Args&& ... args) -> decltype(std::declval<F>()(std::declval<T>(), std::forward<Args>(args)...))
{
return func(std::move(front), std::forward<Args>(args)...);
}
F func;
T front;
};

template<typename F, typename T>
front_binder<cxx::remove_cvref_t<F>, cxx::remove_cvref_t<T>>
bind_front(F&& f, T&& t)
{
return front_binder<cxx::remove_cvref_t<F>, cxx::remove_cvref_t<T>>{
std::forward<F>(f), std::forward<T>(t)
};
}

template<typename Visitor, typename TC, typename ... Args>
visit_result_t<Visitor, const basic_value<TC>&, Args...>
visit_impl(Visitor&& visitor, const basic_value<TC>& v, Args&& ... args);

template<typename Visitor, typename TC, typename ... Args>
visit_result_t<Visitor, basic_value<TC>&, Args...>
visit_impl(Visitor&& visitor, basic_value<TC>& v, Args&& ... args);

template<typename Visitor, typename TC, typename ... Args>
visit_result_t<Visitor, basic_value<TC>, Args...>
visit_impl(Visitor&& visitor, basic_value<TC>&& v, Args&& ... args);


template<typename Visitor>
visit_result_t<Visitor> visit_impl(Visitor&& visitor)
{
return visitor();
}

template<typename Visitor, typename TC, typename ... Args>
visit_result_t<Visitor, basic_value<TC>&, Args...>
visit_impl(Visitor&& visitor, basic_value<TC>& v, Args&& ... args)
{
switch(v.type())
{
case value_t::boolean : {return visitor(v.as_boolean ());}
case value_t::integer : {return visitor(v.as_integer ());}
case value_t::floating : {return visitor(v.as_floating ());}
case value_t::string : {return visitor(v.as_string ());}
case value_t::offset_datetime: {return visitor(v.as_offset_datetime());}
case value_t::local_datetime : {return visitor(v.as_local_datetime ());}
case value_t::local_date : {return visitor(v.as_local_date ());}
case value_t::local_time : {return visitor(v.as_local_time ());}
case value_t::array : {return visitor(v.as_array ());}
case value_t::table : {return visitor(v.as_table ());}
case value_t::boolean : {return visit_impl(bind_front(visitor, std::ref(v.as_boolean ())), std::forward<Args>(args)...);}
case value_t::integer : {return visit_impl(bind_front(visitor, std::ref(v.as_integer ())), std::forward<Args>(args)...);}
case value_t::floating : {return visit_impl(bind_front(visitor, std::ref(v.as_floating ())), std::forward<Args>(args)...);}
case value_t::string : {return visit_impl(bind_front(visitor, std::ref(v.as_string ())), std::forward<Args>(args)...);}
case value_t::offset_datetime: {return visit_impl(bind_front(visitor, std::ref(v.as_offset_datetime())), std::forward<Args>(args)...);}
case value_t::local_datetime : {return visit_impl(bind_front(visitor, std::ref(v.as_local_datetime ())), std::forward<Args>(args)...);}
case value_t::local_date : {return visit_impl(bind_front(visitor, std::ref(v.as_local_date ())), std::forward<Args>(args)...);}
case value_t::local_time : {return visit_impl(bind_front(visitor, std::ref(v.as_local_time ())), std::forward<Args>(args)...);}
case value_t::array : {return visit_impl(bind_front(visitor, std::ref(v.as_array ())), std::forward<Args>(args)...);}
case value_t::table : {return visit_impl(bind_front(visitor, std::ref(v.as_table ())), std::forward<Args>(args)...);}
case value_t::empty : break;
default: break;
}
throw type_error(format_error("[error] toml::visit: toml::basic_value "
"does not have any valid type.", v.location(), "here"), v.location());
}

template<typename Visitor, typename TC>
cxx::return_type_of_t<Visitor, typename basic_value<TC>::boolean_type&>
visit(Visitor&& visitor, basic_value<TC>& v)
template<typename Visitor, typename TC, typename ... Args>
visit_result_t<Visitor, const basic_value<TC>&, Args...>
visit_impl(Visitor&& visitor, const basic_value<TC>& v, Args&& ... args)
{
switch(v.type())
{
case value_t::boolean : {return visitor(v.as_boolean ());}
case value_t::integer : {return visitor(v.as_integer ());}
case value_t::floating : {return visitor(v.as_floating ());}
case value_t::string : {return visitor(v.as_string ());}
case value_t::offset_datetime: {return visitor(v.as_offset_datetime());}
case value_t::local_datetime : {return visitor(v.as_local_datetime ());}
case value_t::local_date : {return visitor(v.as_local_date ());}
case value_t::local_time : {return visitor(v.as_local_time ());}
case value_t::array : {return visitor(v.as_array ());}
case value_t::table : {return visitor(v.as_table ());}
case value_t::boolean : {return visit_impl(bind_front(visitor, std::cref(v.as_boolean ())), std::forward<Args>(args)...);}
case value_t::integer : {return visit_impl(bind_front(visitor, std::cref(v.as_integer ())), std::forward<Args>(args)...);}
case value_t::floating : {return visit_impl(bind_front(visitor, std::cref(v.as_floating ())), std::forward<Args>(args)...);}
case value_t::string : {return visit_impl(bind_front(visitor, std::cref(v.as_string ())), std::forward<Args>(args)...);}
case value_t::offset_datetime: {return visit_impl(bind_front(visitor, std::cref(v.as_offset_datetime())), std::forward<Args>(args)...);}
case value_t::local_datetime : {return visit_impl(bind_front(visitor, std::cref(v.as_local_datetime ())), std::forward<Args>(args)...);}
case value_t::local_date : {return visit_impl(bind_front(visitor, std::cref(v.as_local_date ())), std::forward<Args>(args)...);}
case value_t::local_time : {return visit_impl(bind_front(visitor, std::cref(v.as_local_time ())), std::forward<Args>(args)...);}
case value_t::array : {return visit_impl(bind_front(visitor, std::cref(v.as_array ())), std::forward<Args>(args)...);}
case value_t::table : {return visit_impl(bind_front(visitor, std::cref(v.as_table ())), std::forward<Args>(args)...);}
case value_t::empty : break;
default: break;
}
throw type_error(format_error("[error] toml::visit: toml::basic_value "
"does not have any valid type.", v.location(), "here"), v.location());
}

template<typename Visitor, typename TC>
cxx::return_type_of_t<Visitor, typename basic_value<TC>::boolean_type&&>
visit(Visitor&& visitor, basic_value<TC>&& v)
template<typename Visitor, typename TC, typename ... Args>
visit_result_t<Visitor, basic_value<TC>, Args...>
visit_impl(Visitor&& visitor, basic_value<TC>&& v, Args&& ... args)
{
switch(v.type())
{
case value_t::boolean : {return visitor(std::move(v.as_boolean ()));}
case value_t::integer : {return visitor(std::move(v.as_integer ()));}
case value_t::floating : {return visitor(std::move(v.as_floating ()));}
case value_t::string : {return visitor(std::move(v.as_string ()));}
case value_t::offset_datetime: {return visitor(std::move(v.as_offset_datetime()));}
case value_t::local_datetime : {return visitor(std::move(v.as_local_datetime ()));}
case value_t::local_date : {return visitor(std::move(v.as_local_date ()));}
case value_t::local_time : {return visitor(std::move(v.as_local_time ()));}
case value_t::array : {return visitor(std::move(v.as_array ()));}
case value_t::table : {return visitor(std::move(v.as_table ()));}
case value_t::boolean : {return visit_impl(bind_front(visitor, std::move(v.as_boolean ())), std::forward<Args>(args)...);}
case value_t::integer : {return visit_impl(bind_front(visitor, std::move(v.as_integer ())), std::forward<Args>(args)...);}
case value_t::floating : {return visit_impl(bind_front(visitor, std::move(v.as_floating ())), std::forward<Args>(args)...);}
case value_t::string : {return visit_impl(bind_front(visitor, std::move(v.as_string ())), std::forward<Args>(args)...);}
case value_t::offset_datetime: {return visit_impl(bind_front(visitor, std::move(v.as_offset_datetime())), std::forward<Args>(args)...);}
case value_t::local_datetime : {return visit_impl(bind_front(visitor, std::move(v.as_local_datetime ())), std::forward<Args>(args)...);}
case value_t::local_date : {return visit_impl(bind_front(visitor, std::move(v.as_local_date ())), std::forward<Args>(args)...);}
case value_t::local_time : {return visit_impl(bind_front(visitor, std::move(v.as_local_time ())), std::forward<Args>(args)...);}
case value_t::array : {return visit_impl(bind_front(visitor, std::move(v.as_array ())), std::forward<Args>(args)...);}
case value_t::table : {return visit_impl(bind_front(visitor, std::move(v.as_table ())), std::forward<Args>(args)...);}
case value_t::empty : break;
default: break;
}
throw type_error(format_error("[error] toml::visit: toml::basic_value "
"does not have any valid type.", v.location(), "here"), v.location());
}

} // detail

template<typename Visitor, typename ... Args>
detail::visit_result_t<Visitor, Args...>
visit(Visitor&& visitor, Args&& ... args)
{
return detail::visit_impl(std::forward<Visitor>(visitor), std::forward<Args>(args)...);
}

} // toml
#endif // TOML11_VISIT_HPP

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