simplify SFINAE in to_toml

now is_container returns false when map-like class is passed

README.md

@@ -4,6 +4,7 @@ toml11
 [![Build Status](https://travis-ci.org/ToruNiina/toml11.svg?branch=master)](https://travis-ci.org/ToruNiina/toml11)
 [![Build status](https://ci.appveyor.com/api/projects/status/m2n08a926asvg5mg?svg=true)](https://ci.appveyor.com/project/ToruNiina/toml11)
 [![MIT License](http://img.shields.io/badge/license-MIT-blue.svg?style=flat)](LICENSE)
+[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.1209136.svg)](https://doi.org/10.5281/zenodo.1209136)
 
 c++11 header-only toml parser depending only on c++11 standard library.
 

tests/test_from_toml.cpp

@@ -170,3 +170,22 @@ BOOST_AUTO_TEST_CASE(test_from_toml_tie)
     BOOST_CHECK_EQUAL(ut["val4"].cast<toml::value_t::String >(), "piyo");
 }
 
+BOOST_AUTO_TEST_CASE(test_from_toml_tuple)
+{
+    toml::Array a;
+    a.emplace_back(2);
+    a.emplace_back(7);
+    a.emplace_back(1);
+    a.emplace_back(8);
+    a.emplace_back(2);
+    toml::value v(a);
+
+    std::tuple<int, int, int, int, int> t;
+    toml::from_toml(t, v);
+
+    BOOST_CHECK_EQUAL(std::get<0>(t), 2);
+    BOOST_CHECK_EQUAL(std::get<1>(t), 7);
+    BOOST_CHECK_EQUAL(std::get<2>(t), 1);
+    BOOST_CHECK_EQUAL(std::get<3>(t), 8);
+    BOOST_CHECK_EQUAL(std::get<4>(t), 2);
+}

tests/test_traits.cpp

@@ -74,16 +74,11 @@ BOOST_AUTO_TEST_CASE(test_is_xxx)
     BOOST_CHECK(toml::detail::is_container<std_array_type>::value);
     BOOST_CHECK(toml::detail::is_container<std::set<dummy_type>>::value);
     BOOST_CHECK(toml::detail::is_container<std::unordered_set<std::string>>::value);
-    BOOST_CHECK(toml::detail::is_container<std_map_type>::value);
-    BOOST_CHECK(toml::detail::is_container<std_unordered_map_type>::value);
     BOOST_CHECK(toml::detail::is_container<dummy_container<dummy_type>>::value);
 
+    BOOST_CHECK(!toml::detail::is_container<std_map_type>::value);
+    BOOST_CHECK(!toml::detail::is_container<std_unordered_map_type>::value);
+
     BOOST_CHECK(toml::detail::is_map<std_map_type>::value);
     BOOST_CHECK(toml::detail::is_map<std_unordered_map_type>::value);
-
-    BOOST_CHECK(toml::detail::is_key_convertible<std_map_type>::value);
-    BOOST_CHECK(toml::detail::is_key_convertible<std_unordered_map_type>::value);
 }
-
-
-

toml/from_toml.hpp

@@ -1,66 +1,14 @@
 #ifndef TOML11_FROM_TOML
 #define TOML11_FROM_TOML
-#include "value.hpp"
+#include "get.hpp"
 
 namespace toml
 {
 
-template<typename T, toml::value_t vT = toml::detail::check_type<T>(),
-         typename std::enable_if<(vT != toml::value_t::Unknown &&
-         vT != value_t::Empty), std::nullptr_t>::type = nullptr>
+template<typename T>
 void from_toml(T& x, const toml::value& v)
 {
-    if(v.type() != vT)
-        throw type_error("from_toml: value type: " + stringize(v.type()) +
-                std::string(" is not arguemnt type: ") + stringize(vT));
-    x = v.cast<vT>();
-    return;
-}
-
-template<typename T, toml::value_t vT = toml::detail::check_type<T>(),
-         typename std::enable_if<(vT == toml::value_t::Unknown) &&
-         (!toml::detail::is_map<T>::value) &&
-         toml::detail::is_container<T>::value, std::nullptr_t>::type = nullptr>
-void from_toml(T& x, const toml::value& v)
-{
-    // TODO the case of x is not dynamic container case
-    if(v.type() != value_t::Array)
-        throw type_error("from_toml: value type: " + stringize(v.type()) +
-                         std::string(" is not argument type: Array"));
-    const auto& ar = v.cast<value_t::Array>();
-    try
-    {
-        toml::resize(x, ar.size());
-    }
-    catch(std::invalid_argument& iv)
-    {
-        throw toml::type_error("toml::from_toml: static array size is not enough");
-    }
-    auto iter = x.begin();
-    for(const auto& val : ar)
-    {
-        typename T::value_type v;
-        from_toml(v, val);
-        *iter = std::move(v);
-        ++iter;
-    }
-    return;
-}
-
-template<typename T, toml::value_t vT = toml::detail::check_type<T>(),
-         typename std::enable_if<(vT == toml::value_t::Unknown) &&
-         toml::detail::is_map<T>::value, std::nullptr_t>::type = nullptr>
-void from_toml(T& x, const toml::value& v)
-{
-    if(v.type() != value_t::Table)
-        throw type_error("from_toml: value type: " + stringize(v.type()) +
-                         std::string(" is not argument type: Table"));
-    x.clear();
-    const auto& tb = v.cast<value_t::Table>();
-    for(const auto& kv : tb)
-    {
-        x.insert(kv);
-    }
+    x = toml::get<T>(v);
     return;
 }
 

toml/get.hpp

@@ -6,55 +6,121 @@
 namespace toml
 {
 
-template<typename T, toml::value_t vT = toml::detail::check_type<T>(),
-         typename std::enable_if<(vT != toml::value_t::Unknown &&
-         vT != value_t::Empty), std::nullptr_t>::type = nullptr>
-inline T get(const toml::value& v)
+template<typename T, typename std::enable_if<
+    detail::is_exact_toml_type<T>::value, std::nullptr_t>::type = nullptr>
+inline T& get(value& v)
 {
-    return static_cast<T>(v.cast<vT>());
+    constexpr value_t kind = detail::check_type<T>();
+    return v.cast<kind>();
+}
+
+template<typename T, typename std::enable_if<
+    detail::is_exact_toml_type<T>::value, std::nullptr_t>::type = nullptr>
+inline T const& get(const value& v)
+{
+    constexpr value_t kind = detail::check_type<T>();
+    return v.cast<kind>();
+}
+
+template<typename T, typename std::enable_if<detail::conjunction<
+    detail::negation<detail::is_exact_toml_type<T>>,
+    detail::negation<std::is_same<T, bool>>, std::is_integral<T>
+    >::value, std::nullptr_t>::type = nullptr>
+inline T get(const value& v)
+{
+    return static_cast<T>(v.cast<value_t::Integer>());
+}
+template<typename T, typename std::enable_if<detail::conjunction<
+    detail::negation<detail::is_exact_toml_type<T>>, std::is_floating_point<T>
+    >::value, std::nullptr_t>::type = nullptr>
+inline T get(const value& v)
+{
+    return static_cast<T>(v.cast<value_t::Float>());
 }
 
 // array-like type
-template<typename T, toml::value_t vT = toml::detail::check_type<T>(),
-         typename std::enable_if<(vT == toml::value_t::Unknown) &&
-         (!toml::detail::is_map<T>::value) &&
-         toml::detail::is_container<T>::value, std::nullptr_t>::type = nullptr>
-T get(const toml::value& v)
+template<typename T, typename std::enable_if<detail::conjunction<
+    detail::negation<detail::is_exact_toml_type<T>>, detail::is_container<T>
+    >::value, std::nullptr_t>::type = nullptr>
+T get(const value& v)
 {
-    if(v.type() != value_t::Array)
-        throw type_error("get: value type: " + stringize(v.type()) +
-                         std::string(" is not argument type: Array"));
-
     const auto& ar = v.cast<value_t::Array>();
     T tmp;
     try
     {
-        toml::resize(tmp, ar.size());
+        ::toml::resize(tmp, ar.size());
     }
     catch(std::invalid_argument& iv)
     {
-        throw toml::type_error("toml::get: static array size is not enough");
+        throw type_error("toml::get: static array: size is not enough");
     }
     std::transform(ar.cbegin(), ar.cend(), tmp.begin(),
-        [](toml::value const& elem){return get<typename T::value_type>(elem);});
+        [](value const& elem){return get<typename T::value_type>(elem);});
     return tmp;
 }
 
 // table-like case
-template<typename T, toml::value_t vT = toml::detail::check_type<T>(),
-         typename std::enable_if<(vT == toml::value_t::Unknown) &&
-         toml::detail::is_map<T>::value, std::nullptr_t>::type = nullptr>
+template<typename T, typename std::enable_if<detail::conjunction<
+    detail::negation<detail::is_exact_toml_type<T>>, detail::is_map<T>
+    >::value, std::nullptr_t>::type = nullptr>
 T get(const toml::value& v)
 {
-    if(v.type() != value_t::Table)
-        throw type_error("get: value type: " + stringize(v.type()) +
-                         std::string(" is not argument type: Table"));
-    T tmp;
     const auto& tb = v.cast<value_t::Table>();
+    T tmp;
     for(const auto& kv : tb){tmp.insert(kv);}
     return tmp;
 }
 
+// array -> pair
+template<typename T, typename std::enable_if<detail::is_std_pair<T>::value,
+    std::nullptr_t>::type = nullptr>
+T get(const value& v)
+{
+    using first_type  = typename T::first_type;
+    using second_type = typename T::second_type;
+    const auto& ar = v.cast<value_t::Array>();
+    if(ar.size() != 2)
+    {
+        throw std::out_of_range(
+                "toml::get<std::pair>: value does not have 2 elements.");
+    }
+
+    T tmp;
+    tmp.first  = get<first_type >(ar.at(0));
+    tmp.second = get<second_type>(ar.at(1));
+    return tmp;
+}
+
+namespace detail
+{
+
+template<typename T, std::size_t ...I>
+T get_tuple_impl(const toml::Array& a, index_sequence<I...>)
+{
+    return std::make_tuple(
+        ::toml::get<typename std::tuple_element<I, T>::type>(a.at(I))...);
+}
+
+} // detail
+
+// array -> tuple
+template<typename T, typename std::enable_if<detail::is_std_tuple<T>::value,
+    std::nullptr_t>::type = nullptr>
+T get(const value& v)
+{
+    const auto& ar = v.cast<value_t::Array>();
+    if(ar.size() != std::tuple_size<T>::value)
+    {
+        throw std::out_of_range(
+            "toml::get<std::tuple>: array value does not have " +
+            std::to_string(std::tuple_size<T>::value) +
+            std::string(" elements (array has ") + std::to_string(ar.size()) +
+            std::string(" elements)."));
+    }
+    return detail::get_tuple_impl<T>(ar,
+            detail::make_index_sequence<std::tuple_size<T>::value>{});
+}
+
 //  get_or -----------------------------------------------------------------
 
 template<typename T>

toml/to_toml.hpp

@@ -5,47 +5,76 @@
 namespace toml
 {
 
-template<typename T, toml::value_t vT = toml::detail::check_type<T>(),
-         typename std::enable_if<(vT != toml::value_t::Unknown &&
-         vT != value_t::Empty), std::nullptr_t>::type = nullptr>
-inline toml::value to_toml(T&& x)
+template<typename T, typename std::enable_if<
+    detail::is_exact_toml_type<T>::value, std::nullptr_t>::type = nullptr>
+inline value to_toml(const T& x)
 {
-    return toml::value(std::forward<T>(x));
+    return value(x);
 }
 
-template<typename T, toml::value_t vT = toml::detail::check_type<T>(),
-         typename std::enable_if<(vT == toml::value_t::Unknown) &&
-         (!toml::detail::is_map<T>::value) &&
-         toml::detail::is_container<T>::value, std::nullptr_t>::type = nullptr>
-toml::value to_toml(T&& x)
+template<typename T, typename std::enable_if<detail::conjunction<
+    detail::negation<detail::is_exact_toml_type<T>>, std::is_integral<T>
+    >::value, std::nullptr_t>::type = nullptr>
+inline value to_toml(const T& x)
 {
-    toml::Array tmp; tmp.reserve(std::distance(std::begin(x), std::end(x)));
+    return value(::toml::Integer(x));
+}
+
+template<typename T, typename std::enable_if<detail::conjunction<
+    detail::negation<detail::is_exact_toml_type<T>>, std::is_floating_point<T>
+    >::value, std::nullptr_t>::type = nullptr>
+inline value to_toml(const T& x)
+{
+    return value(::toml::Float(x));
+}
+
+inline value to_toml(const char* str)
+{
+    return value(::toml::String(str));
+}
+
+template<typename T, typename std::enable_if<detail::conjunction<
+    detail::negation<detail::is_exact_toml_type<T>>, detail::is_container<T>
+    >::value, std::nullptr_t>::type = nullptr>
+value to_toml(const T& x)
+{
+    Array tmp;
+    tmp.reserve(std::distance(std::begin(x), std::end(x)));
     for(auto iter = std::begin(x); iter != std::end(x); ++iter)
+    {
         tmp.emplace_back(*iter);
-    return toml::value(std::move(tmp));
+    }
+    return value(std::move(tmp));
 }
 
-template<typename T, toml::value_t vT = toml::detail::check_type<T>(),
-         typename std::enable_if<(vT == toml::value_t::Unknown) &&
-         toml::detail::is_map<T>::value, std::nullptr_t>::type = nullptr>
-toml::value to_toml(T&& x)
+template<typename T, typename std::enable_if<detail::conjunction<
+    detail::negation<detail::is_exact_toml_type<T>>, detail::is_map<T>
+    >::value, std::nullptr_t>::type = nullptr>
+value to_toml(const T& x)
 {
-    toml::Table tmp;
+    Table tmp;
     for(auto iter = std::begin(x); iter != std::end(x); ++iter)
+    {
         tmp.emplace(iter->first, to_toml(iter->second));
-    return toml::value(std::move(tmp));
+    }
+    return value(std::move(tmp));
 }
 
 template<typename T>
-inline toml::value to_toml(std::initializer_list<T> init)
+inline value to_toml(std::initializer_list<T> init)
 {
-    return toml::value(std::move(init));
+    return value(std::move(init));
 }
 
-inline toml::value
-to_toml(std::initializer_list<std::pair<std::string, toml::value>> init)
+inline value to_toml(std::initializer_list<std::pair<std::string, value>> init)
 {
-    return toml::value(std::move(init));
+    return value(std::move(init));
+}
+
+template<typename T>
+inline value to_toml(const value& x)
+{
+    return x;
 }
 
 } // toml

toml/traits.hpp

@@ -1,6 +1,8 @@
 #ifndef TOML11_TRAITS
 #define TOML11_TRAITS
 #include <type_traits>
+#include <utility>
+#include <tuple>
 
 namespace toml
 {
@@ -58,14 +60,54 @@ struct has_resize_method : decltype(has_resize_method_impl::check<T>(nullptr)){}
 #undef decltype(...)
 #endif
 
-template<typename T>
-struct is_container : std::integral_constant<bool,
-    has_iterator<T>::value && has_value_type<T>::value>{};
+template<typename ...> struct conjunction : std::true_type{};
+template<typename T>   struct conjunction<T> : T{};
+template<typename T, typename ... Ts>
+struct conjunction<T, Ts...> :
+    std::conditional<static_cast<bool>(T::value), conjunction<Ts...>, T>::type
+{};
+
+template<typename ...> struct disjunction : std::false_type{};
+template<typename T>   struct disjunction<T> : T {};
+template<typename T, typename ... Ts>
+struct disjunction<T, Ts...> :
+    std::conditional<static_cast<bool>(T::value), T, disjunction<Ts...>>::type
+{};
 
 template<typename T>
-struct is_map : std::integral_constant<bool,
-    has_iterator<T>::value && has_key_type<T>::value &&
-    has_mapped_type<T>::value>{};
+struct negation : std::integral_constant<bool, !static_cast<bool>(T::value)>{};
+
+template<typename T> struct is_std_pair : std::false_type{};
+template<typename T1, typename T2>
+struct is_std_pair<std::pair<T1, T2>> : std::true_type{};
+
+template<typename T> struct is_std_tuple : std::false_type{};
+template<typename ... Ts>
+struct is_std_tuple<std::tuple<Ts...>> : std::true_type{};
+
+// to use toml::get<std::tuple<T1, T2, ...>> in C++11
+template<std::size_t ... Ns> struct index_sequence{};
+
+template<typename IS, std::size_t N> struct push_back_index_sequence{};
+template<std::size_t N, std::size_t ... Ns>
+struct push_back_index_sequence<index_sequence<Ns...>, N>
+{
+    typedef index_sequence<Ns..., N> type;
+};
+
+template<std::size_t N>
+struct index_sequence_maker
+{
+    typedef typename push_back_index_sequence<
+        typename index_sequence_maker<N-1>::type, N>::type type;
+};
+template<>
+struct index_sequence_maker<0>
+{
+    typedef index_sequence<0> type;
+};
+template<std::size_t N>
+using make_index_sequence = typename index_sequence_maker<N-1>::type;
 
 }// detail
 }//toml

toml/value.hpp

@@ -99,33 +99,6 @@ constexpr inline bool is_valid(value_t vt)
     return vt != value_t::Unknown;
 }
 
-template<typename T> struct is_toml_array              : std::false_type{};
-template<>           struct is_toml_array<toml::Array> : std::true_type {};
-template<typename T> struct is_toml_table              : std::false_type{};
-template<>           struct is_toml_table<toml::Table> : std::true_type {};
-
-struct is_key_convertible_impl
-{
-    template<typename T>
-    static std::is_convertible<typename T::key_type, toml::key>
-    check(typename T::key_type*);
-
-    template<typename T> static std::false_type check(...);
-};
-
-/// Intel C++ compiler can not use decltype in parent class declaration, here
-/// is a hack to work around it. https://stackoverflow.com/a/23953090/4692076
-#ifdef __INTEL_COMPILER
-#define decltype(...) std::enable_if<true, decltype(__VA_ARGS__)>::type
-#endif
-
-template<typename T>
-struct is_key_convertible : decltype(is_key_convertible_impl::check<T>(nullptr)){};
-
-#ifdef __INTEL_COMPILER
-#undef decltype(...)
-#endif
-
 template<value_t t> struct toml_default_type{};
 template<> struct toml_default_type<value_t::Boolean >{typedef Boolean  type;};
 template<> struct toml_default_type<value_t::Integer >{typedef Integer  type;};
@@ -137,6 +110,33 @@ template<> struct toml_default_type<value_t::Table   >{typedef Table    type;};
 template<> struct toml_default_type<value_t::Empty   >{typedef void     type;};
 template<> struct toml_default_type<value_t::Unknown >{typedef void     type;};
 
+template<typename T>
+struct is_exact_toml_type : disjunction<
+    std::is_same<T, Boolean >,
+    std::is_same<T, Integer >,
+    std::is_same<T, Float   >,
+    std::is_same<T, String  >,
+    std::is_same<T, Datetime>,
+    std::is_same<T, Array   >,
+    std::is_same<T, Table   >
+    >{};
+
+template<typename T>
+struct is_map : conjunction<
+    has_iterator<T>,
+    has_value_type<T>,
+    has_key_type<T>,
+    has_mapped_type<T>
+    >{};
+
+template<typename T>
+struct is_container : conjunction<
+    negation<is_map<T>>,
+    negation<std::is_same<T, String>>,
+    has_iterator<T>,
+    has_value_type<T>
+    >{};
+
 struct storage_base
 {
     storage_base(): type(toml::value_t::Empty){}
@@ -148,7 +148,8 @@ struct storage_base
 template<typename T>
 struct storage : public storage_base
 {
-    static_assert(is_toml_array<T>::value || is_toml_table<T>::value,
+    static_assert(std::is_same<T, toml::Array>::value ||
+                  std::is_same<T, toml::Table>::value,
                   "toml::detail::storage is for toml::Array or toml::Table!");
     typedef T value_type;
 
@@ -591,21 +592,21 @@ template<typename T, typename std::enable_if<
     value_traits<T>::is_toml_type, std::nullptr_t>::type>
 value::value(T&& v) : type_(toml::detail::check_type<T>())
 {
-    switch_assign<toml::detail::check_type<T>()>::invoke(
-            *this, std::forward<T>(v));
+    constexpr value_t kind = toml::detail::check_type<T>();
+    switch_assign<kind>::invoke(*this, std::forward<T>(v));
 }
 
 template<typename T, typename std::enable_if<
     value_traits<T>::is_toml_type, std::nullptr_t>::type>
 value& value::operator=(T&& v)
 {
+    constexpr value_t kind = toml::detail::check_type<T>();
     if(should_be_cleaned(this->type_))
     {
         switch_clean(this->type_);
     }
-    this->type_ = toml::detail::check_type<T>();
-    switch_assign<toml::detail::check_type<T>()>::invoke(
-            *this, std::forward<T>(v));
+    this->type_ = kind;
+    switch_assign<kind>::invoke(*this, std::forward<T>(v));
     return *this;
 }