path: root/vendor/toml++/impl/table.hpp

// # This file is a part of toml++ and is subject to the the terms of the MIT license.
// # Copyright (c) Mark Gillard <mark.gillard@outlook.com.au>
// # See https://github.com/marzer/tomlplusplus/blob/master/LICENSE for the full license text.
//  SPDX-License-Identifier: MIT
#pragma once

#include "array.hpp"
#include "forward_declarations.hpp"
#include "header_start.hpp"
#include "key.hpp"
#include "make_node.hpp"
#include "node_view.hpp"
#include "std_initializer_list.hpp"
#include "std_map.hpp"

/// \cond
TOML_IMPL_NAMESPACE_START {
  template <bool IsConst>
  struct table_proxy_pair {
    using value_type = std::conditional_t<IsConst, const node, node>;

    const toml::key& first;
    value_type&      second;
  };

  template <bool IsConst>
  class table_iterator {
   private:
    template <bool>
    friend class table_iterator;

    using proxy_type           = table_proxy_pair<IsConst>;
    using mutable_map_iterator = std::map<toml::key, node_ptr, std::less<>>::iterator;
    using const_map_iterator   = std::map<toml::key, node_ptr, std::less<>>::const_iterator;
    using map_iterator = std::conditional_t<IsConst, const_map_iterator, mutable_map_iterator>;

    mutable map_iterator iter_;
    alignas(proxy_type) mutable unsigned char proxy_[sizeof(proxy_type)];
    mutable bool proxy_instantiated_ = false;

    TOML_NODISCARD
    proxy_type* get_proxy() const noexcept {
      if (!proxy_instantiated_) {
        auto p = ::new (static_cast<void*>(proxy_)) proxy_type{iter_->first, *iter_->second.get()};
        proxy_instantiated_ = true;
        return p;
      } else
        return TOML_LAUNDER(reinterpret_cast<proxy_type*>(proxy_));
    }

   public:
    TOML_NODISCARD_CTOR
    table_iterator() noexcept = default;

    TOML_NODISCARD_CTOR
    explicit table_iterator(mutable_map_iterator iter) noexcept  //
        : iter_{iter} {}

    TOML_CONSTRAINED_TEMPLATE(C, bool C = IsConst)
    TOML_NODISCARD_CTOR
    explicit table_iterator(const_map_iterator iter) noexcept  //
        : iter_{iter} {}

    TOML_CONSTRAINED_TEMPLATE(C, bool C = IsConst)
    TOML_NODISCARD_CTOR
    table_iterator(const table_iterator<false>& other) noexcept  //
        : iter_{other.iter_} {}

    TOML_NODISCARD_CTOR
    table_iterator(const table_iterator& other) noexcept  //
        : iter_{other.iter_} {}

    table_iterator& operator=(const table_iterator& rhs) noexcept {
      iter_               = rhs.iter_;
      proxy_instantiated_ = false;
      return *this;
    }

    using value_type        = table_proxy_pair<IsConst>;
    using reference         = value_type&;
    using pointer           = value_type*;
    using difference_type   = typename std::iterator_traits<map_iterator>::difference_type;
    using iterator_category = typename std::iterator_traits<map_iterator>::iterator_category;

    table_iterator& operator++() noexcept  // ++pre
    {
      ++iter_;
      proxy_instantiated_ = false;
      return *this;
    }

    table_iterator operator++(int) noexcept  // post++
    {
      table_iterator out{iter_};
      ++iter_;
      proxy_instantiated_ = false;
      return out;
    }

    table_iterator& operator--() noexcept  // --pre
    {
      --iter_;
      proxy_instantiated_ = false;
      return *this;
    }

    table_iterator operator--(int) noexcept  // post--
    {
      table_iterator out{iter_};
      --iter_;
      proxy_instantiated_ = false;
      return out;
    }

    TOML_PURE_INLINE_GETTER
    reference operator*() const noexcept { return *get_proxy(); }

    TOML_PURE_INLINE_GETTER
    pointer operator->() const noexcept { return get_proxy(); }

    TOML_PURE_INLINE_GETTER
    explicit operator const map_iterator&() const noexcept { return iter_; }

    TOML_CONSTRAINED_TEMPLATE(!C, bool C = IsConst)
    TOML_PURE_INLINE_GETTER
    explicit operator const const_map_iterator() const noexcept { return iter_; }

    TOML_PURE_INLINE_GETTER
    friend bool operator==(const table_iterator& lhs, const table_iterator& rhs) noexcept {
      return lhs.iter_ == rhs.iter_;
    }

    TOML_PURE_INLINE_GETTER
    friend bool operator!=(const table_iterator& lhs, const table_iterator& rhs) noexcept {
      return lhs.iter_ != rhs.iter_;
    }
  };

  struct table_init_pair {
    mutable toml::key key;
    mutable node_ptr  value;

    template <typename K, typename V>
    TOML_NODISCARD_CTOR table_init_pair(K&& k, V&& v,
                                        value_flags flags = preserve_source_value_flags)  //
        : key{static_cast<K&&>(k)}, value{make_node(static_cast<V&&>(v), flags)} {}
  };
}
TOML_IMPL_NAMESPACE_END;
/// \endcond

TOML_NAMESPACE_START {
  /// \brief A BidirectionalIterator for iterating over key-value pairs in a toml::table.
  using table_iterator = POXY_IMPLEMENTATION_DETAIL(impl::table_iterator<false>);

  /// \brief A BidirectionalIterator for iterating over const key-value pairs in a toml::table.
  using const_table_iterator = POXY_IMPLEMENTATION_DETAIL(impl::table_iterator<true>);

  /// \brief	A TOML table.
  ///
  /// \detail The interface of this type is modeled after std::map, with some
  /// 		additional considerations made for the heterogeneous nature of a
  /// 		TOML table.
  ///
  /// \cpp
  /// toml::table tbl = toml::parse(R"(
  ///
  /// 	[animals]
  /// 	cats = [ "tiger", "lion", "puma" ]
  /// 	birds = [ "macaw", "pigeon", "canary" ]
  /// 	fish = [ "salmon", "trout", "carp" ]
  ///
  /// )"sv);
  ///
  /// // operator[] retrieves node-views
  /// std::cout << "cats: " << tbl["animals"]["cats"] << "\n";
  /// std::cout << "fish[1]: " << tbl["animals"]["fish"][1] << "\n";
  ///
  /// // at_path() does fully-qualified "toml path" lookups
  /// std::cout << "cats: " << tbl.at_path("animals.cats") << "\n";
  /// std::cout << "fish[1]: " << tbl.at_path("animals.fish[1]") << "\n";
  /// \ecpp
  ///
  /// \out
  /// cats: ['tiger', 'lion', 'puma']
  /// fish[1] : 'trout'
  /// cats : ['tiger', 'lion', 'puma']
  /// fish[1] : 'trout'
  /// \eout
  class TOML_EXPORTED_CLASS table : public node {
   private:
    /// \cond

    using map_type           = std::map<toml::key, impl::node_ptr, std::less<>>;
    using map_pair           = std::pair<const toml::key, impl::node_ptr>;
    using map_iterator       = typename map_type::iterator;
    using const_map_iterator = typename map_type::const_iterator;
    map_type map_;

    bool inline_ = false;

    TOML_NODISCARD_CTOR
    TOML_EXPORTED_MEMBER_FUNCTION
    table(const impl::table_init_pair*, const impl::table_init_pair*);

    /// \endcond

   public:
    /// \brief	Default constructor.
    TOML_NODISCARD_CTOR
    TOML_EXPORTED_MEMBER_FUNCTION
    table() noexcept;

    TOML_EXPORTED_MEMBER_FUNCTION
    ~table() noexcept;

    /// \brief	Copy constructor.
    TOML_NODISCARD_CTOR
    TOML_EXPORTED_MEMBER_FUNCTION
    table(const table&);

    /// \brief	Move constructor.
    TOML_NODISCARD_CTOR
    TOML_EXPORTED_MEMBER_FUNCTION
    table(table&& other) noexcept;

    /// \brief	Constructs a table with one or more initial key-value pairs.
    ///
    /// \detail \cpp
    /// auto tbl = toml::table{
    ///		{ "foo", 1 },
    ///		{ "bar", 2.0 },
    ///		{ "kek", "three" }
    ///	};
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// { foo = 1, bar = 2.0, kek = "three" }
    /// \eout
    ///
    /// \param 	kvps	A list of key-value pairs used to initialize the table.
    TOML_NODISCARD_CTOR
    TOML_EXPORTED_MEMBER_FUNCTION
    explicit table(std::initializer_list<impl::table_init_pair> kvps)  //
        : table(kvps.begin(), kvps.end()) {}

    /// \brief	Copy-assignment operator.
    TOML_EXPORTED_MEMBER_FUNCTION
    table& operator=(const table&);

    /// \brief	Move-assignment operator.
    TOML_EXPORTED_MEMBER_FUNCTION
    table& operator=(table&& rhs) noexcept;

    /// \name Type checks
    /// @{

    /// \brief Returns #toml::node_type::table.
    TOML_CONST_INLINE_GETTER
    node_type type() const noexcept final { return node_type::table; }

    TOML_PURE_GETTER
    TOML_EXPORTED_MEMBER_FUNCTION
    bool is_homogeneous(node_type ntype) const noexcept final;

    TOML_PURE_GETTER
    TOML_EXPORTED_MEMBER_FUNCTION
    bool is_homogeneous(node_type ntype, node*& first_nonmatch) noexcept final;

    TOML_PURE_GETTER
    TOML_EXPORTED_MEMBER_FUNCTION
    bool is_homogeneous(node_type ntype, const node*& first_nonmatch) const noexcept final;

    /// \cond
    template <typename ElemType = void>
    TOML_PURE_GETTER bool is_homogeneous() const noexcept {
      using type = impl::remove_cvref<impl::unwrap_node<ElemType>>;
      static_assert(std::is_void_v<type> || toml::is_value<type> || toml::is_container<type>,
                    "The template type argument of table::is_homogeneous() must be void or one "
                    "of:" TOML_SA_UNWRAPPED_NODE_TYPE_LIST);

      return is_homogeneous(impl::node_type_of<type>);
    }
    /// \endcond

    /// \brief Returns `true`.
    TOML_CONST_INLINE_GETTER
    bool is_table() const noexcept final { return true; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_array() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_PURE_GETTER
    bool is_array_of_tables() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_value() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_string() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_integer() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_floating_point() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_number() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_boolean() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_date() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_time() const noexcept final { return false; }

    /// \brief Returns `false`.
    TOML_CONST_INLINE_GETTER
    bool is_date_time() const noexcept final { return false; }

    /// @}

    /// \name Type casts
    /// @{

    /// \brief Returns a pointer to the table.
    TOML_CONST_INLINE_GETTER
    table* as_table() noexcept final { return this; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    array* as_array() noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    toml::value<std::string>* as_string() noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    toml::value<int64_t>* as_integer() noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    toml::value<double>* as_floating_point() noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    toml::value<bool>* as_boolean() noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    toml::value<date>* as_date() noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    toml::value<time>* as_time() noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    toml::value<date_time>* as_date_time() noexcept final { return nullptr; }

    /// \brief Returns a const-qualified pointer to the table.
    TOML_CONST_INLINE_GETTER
    const table* as_table() const noexcept final { return this; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    const array* as_array() const noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    const toml::value<std::string>* as_string() const noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    const toml::value<int64_t>* as_integer() const noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    const toml::value<double>* as_floating_point() const noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    const toml::value<bool>* as_boolean() const noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    const toml::value<date>* as_date() const noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    const toml::value<time>* as_time() const noexcept final { return nullptr; }

    /// \brief Returns `nullptr`.
    TOML_CONST_INLINE_GETTER
    const toml::value<date_time>* as_date_time() const noexcept final { return nullptr; }

    /// @}

    /// \name Metadata
    /// @{

    /// \brief	Returns true if this table is an inline table.
    ///
    /// \remarks Runtime-constructed tables (i.e. those not created during
    /// 		 parsing) are not inline by default.
    TOML_PURE_INLINE_GETTER
    bool is_inline() const noexcept { return inline_; }

    /// \brief	Sets whether this table is a TOML inline table.
    ///
    /// \detail \godbolt{an9xdj}
    ///
    /// \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 1 },
    ///		{ "b", 2 },
    ///		{ "c", 3 },
    ///		{ "d", toml::table{ { "e", 4 } } }
    ///	};
    /// std::cout << "is inline? "sv << tbl.is_inline() << "\n";
    /// std::cout << tbl << "\n\n";
    ///
    /// tbl.is_inline(!tbl.is_inline());
    /// std::cout << "is inline? "sv << tbl.is_inline() << "\n";
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// is inline? false
    /// a = 1
    /// b = 2
    /// c = 3
    ///
    /// [d]
    /// e = 4
    ///
    ///
    /// is inline? true
    /// { a = 1, b = 2, c = 3, d = { e = 4 } }
    /// \eout
    ///
    /// \remarks A table being 'inline' is only relevent during printing;
    /// 		 it has no effect on the general functionality of the table
    /// 		 object.
    ///
    /// \param 	val	The new value for 'inline'.
    void is_inline(bool val) noexcept { inline_ = val; }

    /// @}

    /// \name Value retrieval
    /// @{

    /// \brief	Gets the node at a specific key.
    ///
    /// \detail \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 42, },
    ///		{ "b", "is the meaning of life, apparently." }
    ///	};
    ///	std::cout << R"(node ["a"] exists: )"sv << !!arr.get("a") << "\n";
    ///	std::cout << R"(node ["b"] exists: )"sv << !!arr.get("b") << "\n";
    ///	std::cout << R"(node ["c"] exists: )"sv << !!arr.get("c") << "\n";
    /// if (auto val = arr.get("a"))
    ///		std::cout << R"(node ["a"] was an )"sv << val->type() << "\n";
    /// \ecpp
    ///
    /// \out
    /// node ["a"] exists: true
    /// node ["b"] exists: true
    /// node ["c"] exists: false
    /// node ["a"] was an integer
    /// \eout
    ///
    /// \param 	key	The node's key.
    ///
    /// \returns	A pointer to the node at the specified key, or nullptr.
    TOML_PURE_GETTER
    TOML_EXPORTED_MEMBER_FUNCTION
    node* get(std::string_view key) noexcept;

    /// \brief	Gets the node at a specific key (const overload).
    ///
    /// \param 	key	The node's key.
    ///
    /// \returns	A pointer to the node at the specified key, or nullptr.
    TOML_PURE_INLINE_GETTER
    const node* get(std::string_view key) const noexcept {
      return const_cast<table&>(*this).get(key);
    }

#if TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Gets the node at a specific key.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \param 	key	The node's key.
    ///
    /// \returns	A pointer to the node at the specified key, or nullptr.
    TOML_NODISCARD
    node* get(std::wstring_view key) {
      if (empty()) return nullptr;

      return get(impl::narrow(key));
    }

    /// \brief	Gets the node at a specific key (const overload).
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \param 	key	The node's key.
    ///
    /// \returns	A pointer to the node at the specified key, or nullptr.
    TOML_NODISCARD
    const node* get(std::wstring_view key) const { return const_cast<table&>(*this).get(key); }

#endif  // TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Gets the node at a specific key if it is a particular type.
    ///
    /// \detail \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 42, },
    ///		{ "b", "is the meaning of life, apparently." }
    ///	};
    /// if (auto val = arr.get_as<int64_t>("a"))
    ///		std::cout << R"(node ["a"] was an integer with value )"sv << **val << "\n";
    /// \ecpp
    ///
    /// \out
    /// node ["a"] was an integer with value 42
    /// \eout
    ///
    /// \tparam	T		One of the TOML node or value types.
    /// \param 	key		The node's key.
    ///
    /// \returns	A pointer to the node at the specified key if it was of the given type, or
    /// nullptr.
    template <typename T>
    TOML_PURE_GETTER impl::wrap_node<T>* get_as(std::string_view key) noexcept {
      const auto n = this->get(key);
      return n ? n->template as<T>() : nullptr;
    }

    /// \brief	Gets the node at a specific key if it is a particular type (const overload).
    ///
    /// \tparam	T		One of the TOML node or value types.
    /// \param 	key		The node's key.
    ///
    /// \returns	A pointer to the node at the specified key if it was of the given type, or
    /// nullptr.
    template <typename T>
    TOML_PURE_GETTER const impl::wrap_node<T>* get_as(std::string_view key) const noexcept {
      return const_cast<table&>(*this).template get_as<T>(key);
    }

#if TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Gets the node at a specific key if it is a particular type.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \tparam	T		One of the TOML node or value types.
    /// \param 	key		The node's key.
    ///
    /// \returns	A pointer to the node at the specified key if it was of the given type, or
    /// nullptr.
    template <typename T>
    TOML_NODISCARD impl::wrap_node<T>* get_as(std::wstring_view key) {
      if (empty()) return nullptr;

      return get_as<T>(impl::narrow(key));
    }

    /// \brief	Gets the node at a specific key if it is a particular type (const overload).
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \tparam	T		One of the TOML node or value types.
    /// \param 	key		The node's key.
    ///
    /// \returns	A pointer to the node at the specified key if it was of the given type, or
    /// nullptr.
    template <typename T>
    TOML_NODISCARD const impl::wrap_node<T>* get_as(std::wstring_view key) const {
      return const_cast<table&>(*this).template get_as<T>(key);
    }

#endif  // TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Gets a reference to the element at a specific key, throwing `std::out_of_range` if
    /// none existed.
    TOML_NODISCARD
    TOML_EXPORTED_MEMBER_FUNCTION
    node& at(std::string_view key);

    /// \brief	Gets a reference to the element at a specific key, throwing `std::out_of_range` if
    /// none existed.
    TOML_NODISCARD
    const node& at(std::string_view key) const { return const_cast<table&>(*this).at(key); }

#if TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Gets a reference to the element at a specific key, throwing `std::out_of_range` if
    /// none existed.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    TOML_NODISCARD
    node& at(std::wstring_view key) { return at(impl::narrow(key)); }

    /// \brief	Gets a reference to the element at a specific key, throwing `std::out_of_range` if
    /// none existed.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    TOML_NODISCARD
    const node& at(std::wstring_view key) const { return const_cast<table&>(*this).at(key); }

#endif  // TOML_ENABLE_WINDOWS_COMPAT

    /// @}

    /// \name Iteration
    /// @{

    /// \brief A BidirectionalIterator for iterating over key-value pairs in a toml::table.
    using iterator = toml::table_iterator;

    /// \brief A BidirectionalIterator for iterating over const key-value pairs in a toml::table.
    using const_iterator = toml::const_table_iterator;

    /// \brief	Returns an iterator to the first key-value pair.
    TOML_PURE_INLINE_GETTER
    iterator begin() noexcept { return iterator{map_.begin()}; }

    /// \brief	Returns an iterator to the first key-value pair.
    TOML_PURE_INLINE_GETTER
    const_iterator begin() const noexcept { return const_iterator{map_.cbegin()}; }

    /// \brief	Returns an iterator to the first key-value pair.
    TOML_PURE_INLINE_GETTER
    const_iterator cbegin() const noexcept { return const_iterator{map_.cbegin()}; }

    /// \brief	Returns an iterator to one-past-the-last key-value pair.
    TOML_PURE_INLINE_GETTER
    iterator end() noexcept { return iterator{map_.end()}; }

    /// \brief	Returns an iterator to one-past-the-last key-value pair.
    TOML_PURE_INLINE_GETTER
    const_iterator end() const noexcept { return const_iterator{map_.cend()}; }

    /// \brief	Returns an iterator to one-past-the-last key-value pair.
    TOML_PURE_INLINE_GETTER
    const_iterator cend() const noexcept { return const_iterator{map_.cend()}; }

   private:
    /// \cond

    template <typename T, typename Table>
    using for_each_value_ref =
        impl::copy_cvref<impl::wrap_node<impl::remove_cvref<impl::unwrap_node<T>>>, Table>;

    template <typename Func, typename Table, typename T>
    using can_for_each =
        std::disjunction<std::is_invocable<Func, const key&, for_each_value_ref<T, Table>>,  //
                         std::is_invocable<Func, for_each_value_ref<T, Table>>>;

    template <typename Func, typename Table, typename T>
    using can_for_each_nothrow = std::conditional_t<
        // first form
        std::is_invocable_v<Func, const key&, for_each_value_ref<T, Table>>,
        std::is_nothrow_invocable<Func, const key&, for_each_value_ref<T, Table>>,
        std::conditional_t<
            // second form
            std::is_invocable_v<Func, for_each_value_ref<T, Table>>,
            std::is_nothrow_invocable<Func, for_each_value_ref<T, Table>>, std::false_type>>;

    template <typename Func, typename Table>
    using can_for_each_any =
        std::disjunction<can_for_each<Func, Table, table>, can_for_each<Func, Table, array>,
                         can_for_each<Func, Table, std::string>, can_for_each<Func, Table, int64_t>,
                         can_for_each<Func, Table, double>, can_for_each<Func, Table, bool>,
                         can_for_each<Func, Table, date>, can_for_each<Func, Table, time>,
                         can_for_each<Func, Table, date_time>>;

    template <typename Func, typename Table, typename T>
    using for_each_is_nothrow_one =
        std::disjunction<std::negation<can_for_each<Func, Table, T>>,  //
                         can_for_each_nothrow<Func, Table, T>>;

    template <typename Func, typename Table>
    using for_each_is_nothrow = std::conjunction<
        for_each_is_nothrow_one<Func, Table, table>, for_each_is_nothrow_one<Func, Table, array>,
        for_each_is_nothrow_one<Func, Table, std::string>,
        for_each_is_nothrow_one<Func, Table, int64_t>, for_each_is_nothrow_one<Func, Table, double>,
        for_each_is_nothrow_one<Func, Table, bool>, for_each_is_nothrow_one<Func, Table, date>,
        for_each_is_nothrow_one<Func, Table, time>,
        for_each_is_nothrow_one<Func, Table, date_time>>;

    template <typename Func, typename Table>
    static void do_for_each(Func&& visitor, Table&& tbl)  //
        noexcept(for_each_is_nothrow<Func&&, Table&&>::value) {
      static_assert(
          can_for_each_any<Func&&, Table&&>::value,
          "TOML table for_each visitors must be invocable for at least one of the toml::node "
          "specializations:" TOML_SA_NODE_TYPE_LIST);

      using kvp_type = impl::copy_cv<map_pair, std::remove_reference_t<Table>>;

      for (kvp_type& kvp : tbl.map_) {
        using node_ref = impl::copy_cvref<toml::node, Table&&>;
        static_assert(std::is_reference_v<node_ref>);

#if TOML_RETURN_BOOL_FROM_FOR_EACH_BROKEN

#ifndef TOML_RETURN_BOOL_FROM_FOR_EACH_BROKEN_ACKNOWLEDGED
        static_assert(impl::always_false<Func, Table, kvp_type, node_ref>,  //
                      TOML_RETURN_BOOL_FROM_FOR_EACH_BROKEN_MESSAGE);
#endif

        static_cast<node_ref>(*kvp.second)
            .visit([&]([[maybe_unused]] auto&& v)  //
                   noexcept(for_each_is_nothrow_one<Func&&, Table&&, decltype(v)>::value) {
                     using value_ref = for_each_value_ref<decltype(v), Table&&>;
                     static_assert(std::is_reference_v<value_ref>);

                     // func(key, val)
                     if constexpr (std::is_invocable_v<Func&&, const key&, value_ref>) {
                       static_cast<Func&&>(visitor)(static_cast<const key&>(kvp.first),
                                                    static_cast<value_ref>(v));
                     }

                     // func(val)
                     else if constexpr (std::is_invocable_v<Func&&, value_ref>) {
                       static_cast<Func&&>(visitor)(static_cast<value_ref>(v));
                     }
                   });

#else
        const auto keep_going =
            static_cast<node_ref>(*kvp.second)
                .visit([&]([[maybe_unused]] auto&& v)  //
                       noexcept(for_each_is_nothrow_one<Func&&, Table&&, decltype(v)>::value) {
                         using value_ref = for_each_value_ref<decltype(v), Table&&>;
                         static_assert(std::is_reference_v<value_ref>);

                         // func(key, val)
                         if constexpr (std::is_invocable_v<Func&&, const key&, value_ref>) {
                           using return_type = decltype(static_cast<Func&&>(visitor)(
                               static_cast<const key&>(kvp.first), static_cast<value_ref>(v)));

                           if constexpr (impl::is_constructible_or_convertible<bool, return_type>) {
                             return static_cast<bool>(static_cast<Func&&>(visitor)(
                                 static_cast<const key&>(kvp.first), static_cast<value_ref>(v)));
                           } else {
                             static_cast<Func&&>(visitor)(static_cast<const key&>(kvp.first),
                                                          static_cast<value_ref>(v));
                             return true;
                           }
                         }

                         // func(val)
                         else if constexpr (std::is_invocable_v<Func&&, value_ref>) {
                           using return_type =
                               decltype(static_cast<Func&&>(visitor)(static_cast<value_ref>(v)));

                           if constexpr (impl::is_constructible_or_convertible<bool, return_type>) {
                             return static_cast<bool>(
                                 static_cast<Func&&>(visitor)(static_cast<value_ref>(v)));
                           } else {
                             static_cast<Func&&>(visitor)(static_cast<value_ref>(v));
                             return true;
                           }
                         }

                         // visitor not compatible with this particular type
                         else
                           return true;
                       });

        if (!keep_going) return;
#endif
      }
    }

    /// \endcond

   public:
    /// \brief	Invokes a visitor on each key-value pair in the table.
    ///
    /// \tparam	Func	A callable type invocable with one of the following signatures:
    ///					<ul>
    ///					<li> `func(key, val)`
    ///					<li> `func(val)`
    ///					</ul>
    ///					Where:
    ///					<ul>
    ///					<li> `key` will recieve a const reference to a toml::key
    ///					<li> `val` will recieve the value as it's concrete type with cvref-qualifications
    ///matching the table
    ///					</ul>
    ///					Visitors returning `bool` (or something convertible to `bool`) will cause iteration
    ///to 					stop if they return `false`.
    ///
    /// \param 	visitor	The visitor object.
    ///
    /// \returns A reference to the table.
    ///
    /// \details \cpp
    /// toml::table tbl{
    ///		{ "0",  0      },
    /// 	{ "1",  1      },
    /// 	{ "2",  2      },
    /// 	{ "3",  3.0    },
    /// 	{ "4",  "four" },
    /// 	{ "5",  "five" },
    /// 	{ "6",  6      }
    /// };
    ///
    /// // select only the integers using a strongly-typed visitor
    /// tbl.for_each([](toml::value<int64_t>& val)
    /// {
    /// 	std::cout << val << ", ";
    /// });
    /// std::cout << "\n";
    ///
    /// // select all the numeric values using a generic visitor + is_number<> metafunction
    /// tbl.for_each([](auto&& val)
    /// {
    /// 	if constexpr (toml::is_number<decltype(val)>)
    /// 		std::cout << val << ", ";
    /// });
    /// std::cout << "\n";
    ///
    /// // select all the numeric values until we encounter something non-numeric
    /// tbl.for_each([](auto&& val)
    /// {
    ///		if constexpr (toml::is_number<decltype(val)>)
    ///		{
    ///			std::cout << val << ", ";
    ///			return true; // "keep going"
    ///		}
    ///		else
    ///			return false; // "stop!"
    ///
    /// });
    /// std::cout << "\n\n";
    ///
    /// // visitors may also recieve the key
    /// tbl.for_each([](const toml::key& key, auto&& val)
    /// {
    ///		std::cout << key << ": " << val << "\n";
    /// });
    ///
    /// \ecpp
    /// \out
    /// 0, 1, 2, 6,
    /// 0, 1, 2, 3.0, 6,
    /// 0, 1, 2, 3.0,
    ///
    /// 0: 0
    /// 1: 1
    /// 2: 2
    /// 3: 3.0
    /// 4: 'four'
    /// 5: 'five'
    /// 6: 6
    /// \eout
    ///
    /// \see node::visit()
    template <typename Func>
    table& for_each(Func&& visitor) &  //
        noexcept(for_each_is_nothrow<Func&&, table&>::value) {
      do_for_each(static_cast<Func&&>(visitor), *this);
      return *this;
    }

    /// \brief	Invokes a visitor on each key-value pair in the table (rvalue overload).
    template <typename Func>
    table&& for_each(Func&& visitor) &&  //
        noexcept(for_each_is_nothrow<Func&&, table&&>::value) {
      do_for_each(static_cast<Func&&>(visitor), static_cast<table&&>(*this));
      return static_cast<table&&>(*this);
    }

    /// \brief	Invokes a visitor on each key-value pair in the table (const lvalue overload).
    template <typename Func>
    const table& for_each(Func&& visitor) const&  //
        noexcept(for_each_is_nothrow<Func&&, const table&>::value) {
      do_for_each(static_cast<Func&&>(visitor), *this);
      return *this;
    }

    /// \brief	Invokes a visitor on each key-value pair in the table (const rvalue overload).
    template <typename Func>
    const table&& for_each(Func&& visitor) const&&  //
        noexcept(for_each_is_nothrow<Func&&, const table&&>::value) {
      do_for_each(static_cast<Func&&>(visitor), static_cast<const table&&>(*this));
      return static_cast<const table&&>(*this);
    }

    /// @}

    /// \name Size and Capacity
    /// @{

    /// \brief	Returns true if the table is empty.
    TOML_PURE_INLINE_GETTER
    bool empty() const noexcept { return map_.empty(); }

    /// \brief	Returns the number of key-value pairs in the table.
    TOML_PURE_INLINE_GETTER
    size_t size() const noexcept { return map_.size(); }

    /// @}

    /// \name Searching
    /// @{

   private:
    /// \cond

    TOML_PURE_GETTER
    TOML_EXPORTED_MEMBER_FUNCTION
    map_iterator get_lower_bound(std::string_view) noexcept;

    /// \endcond

   public:
    /// \brief Returns an iterator to the first key-value pair with key that is _not less_ than the
    /// given key.
    ///
    /// \returns	An iterator to the first matching key-value pair, or #end().
    TOML_PURE_GETTER
    iterator lower_bound(std::string_view key) noexcept { return iterator{get_lower_bound(key)}; }

    /// \brief Returns a const iterator to the first key-value pair with key that is _not less_ than
    /// the given key.
    ///
    /// \returns	An iterator to the first matching key-value pair, or #end().
    TOML_PURE_GETTER
    const_iterator lower_bound(std::string_view key) const noexcept {
      return const_iterator{const_cast<table&>(*this).get_lower_bound(key)};
    }

#if TOML_ENABLE_WINDOWS_COMPAT

    /// \brief Returns an iterator to the first key-value pair with key that is _not less_ than the
    /// given key.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \returns	An iterator to the first matching key-value pair, or #end().
    TOML_NODISCARD
    iterator lower_bound(std::wstring_view key) {
      if (empty()) return end();

      return lower_bound(impl::narrow(key));
    }

    /// \brief Returns a const iterator to the first key-value pair with key that is _not less_ than
    /// the given key.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \returns	An iterator to the first matching key-value pair, or #end().
    TOML_NODISCARD
    const_iterator lower_bound(std::wstring_view key) const {
      if (empty()) return end();

      return lower_bound(impl::narrow(key));
    }

#endif  // TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Gets an iterator to the node at a specific key.
    ///
    /// \param 	key	The node's key.
    ///
    /// \returns	An iterator to the node at the specified key, or end().
    TOML_PURE_GETTER
    TOML_EXPORTED_MEMBER_FUNCTION
    iterator find(std::string_view key) noexcept;

    /// \brief	Gets an iterator to the node at a specific key (const overload)
    ///
    /// \param 	key	The node's key.
    ///
    /// \returns	A const iterator to the node at the specified key, or cend().
    TOML_PURE_GETTER
    TOML_EXPORTED_MEMBER_FUNCTION
    const_iterator find(std::string_view key) const noexcept;

    /// \brief	Returns true if the table contains a node at the given key.
    TOML_PURE_GETTER
    bool contains(std::string_view key) const noexcept { return get(key) != nullptr; }

#if TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Gets an iterator to the node at a specific key.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \param 	key	The node's key.
    ///
    /// \returns	An iterator to the node at the specified key, or end().
    TOML_NODISCARD
    iterator find(std::wstring_view key) {
      if (empty()) return end();

      return find(impl::narrow(key));
    }

    /// \brief	Gets an iterator to the node at a specific key (const overload).
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \param 	key	The node's key.
    ///
    /// \returns	A const iterator to the node at the specified key, or cend().
    TOML_NODISCARD
    const_iterator find(std::wstring_view key) const { return find(impl::narrow(key)); }

    /// \brief	Returns true if the table contains a node at the given key.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    TOML_NODISCARD
    bool contains(std::wstring_view key) const { return contains(impl::narrow(key)); }

#endif  // TOML_ENABLE_WINDOWS_COMPAT

    /// @}

    /// \name Erasure
    /// @{

   private:
    /// \cond

    TOML_EXPORTED_MEMBER_FUNCTION
    map_iterator erase(const_map_iterator) noexcept;

    TOML_EXPORTED_MEMBER_FUNCTION
    map_iterator erase(const_map_iterator, const_map_iterator) noexcept;

    /// \endcond

   public:
    /// \brief	Removes the specified key-value pair from the table.
    ///
    /// \detail \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 1 },
    ///		{ "b", 2 },
    ///		{ "c", 3 }
    ///	};
    /// std::cout << tbl << "\n";
    ///
    /// tbl.erase(tbl.begin() + 1);
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// { a = 1, b = 2, c = 3 }
    /// { a = 1, c = 3 }
    /// \eout
    ///
    /// \param 	pos		Iterator to the key-value pair being erased.
    ///
    /// \returns Iterator to the first key-value pair immediately following the removed key-value
    /// pair.
    iterator erase(iterator pos) noexcept { return iterator{erase(const_map_iterator{pos})}; }

    /// \brief	Removes the specified key-value pair from the table (const iterator overload).
    ///
    /// \detail \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 1 },
    ///		{ "b", 2 },
    ///		{ "c", 3 }
    ///	};
    /// std::cout << tbl << "\n";
    ///
    /// tbl.erase(tbl.cbegin() + 1);
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// { a = 1, b = 2, c = 3 }
    /// { a = 1, c = 3 }
    /// \eout
    ///
    /// \param 	pos		Iterator to the key-value pair being erased.
    ///
    /// \returns Iterator to the first key-value pair immediately following the removed key-value
    /// pair.
    iterator erase(const_iterator pos) noexcept { return iterator{erase(const_map_iterator{pos})}; }

    /// \brief	Removes the key-value pairs in the range [first, last) from the table.
    ///
    /// \detail \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 1 },
    ///		{ "b", "bad" },
    ///		{ "c", "karma" },
    ///		{ "d", 2 }
    ///	};
    /// std::cout << tbl << "\n";
    ///
    /// tbl.erase(tbl.cbegin() + 1, tbl.cbegin() + 3);
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// { a = 1, b = "bad", c = "karma", d = 2 }
    /// { a = 1, d = 2 }
    /// \eout
    ///
    /// \param 	begin	Iterator to the first key-value pair being erased.
    /// \param 	end		Iterator to the one-past-the-last key-value pair being erased.
    ///
    /// \returns Iterator to the first key-value pair immediately following the last removed
    /// key-value pair.
    iterator erase(const_iterator begin, const_iterator end) noexcept {
      return iterator{erase(const_map_iterator{begin}, const_map_iterator{end})};
    }

    /// \brief	Removes the value with the given key from the table.
    ///
    /// \detail \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 1 },
    ///		{ "b", 2 },
    ///		{ "c", 3 }
    ///	};
    /// std::cout << tbl << "\n";
    ///
    /// std::cout << tbl.erase("b") << "\n";
    /// std::cout << tbl.erase("not an existing key") << "\n";
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// { a = 1, b = 2, c = 3 }
    /// true
    /// false
    /// { a = 1, c = 3 }
    /// \eout
    ///
    /// \param 	key		Key to erase.
    ///
    /// \returns Number of elements removed (0 or 1).
    TOML_EXPORTED_MEMBER_FUNCTION
    size_t erase(std::string_view key) noexcept;

#if TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Removes the value with the given key from the table.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \param 	key		Key to erase.
    ///
    /// \returns Number of elements removed (0 or 1).
    size_t erase(std::wstring_view key) {
      if (empty()) return false;

      return erase(impl::narrow(key));
    }

#endif  // TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Removes empty child arrays and tables.
    ///
    /// \detail \cpp
    ///
    /// auto tbl = toml::table{ { "a", 1 }, { "b", toml::array{ } }, { "c", toml::array{
    /// toml::table{}, toml::array{} } } }; std::cout << arr << "\n";
    ///
    /// arr.prune();
    /// std::cout << arr << "\n";
    /// \ecpp
    ///
    /// \out
    /// { a = 1, b = [], c = [ {}, [] ] }
    /// { a = 1 }
    /// \eout
    ///
    /// \param recursive Should child arrays and tables themselves be pruned?
    ///
    /// \returns A reference to the table.
    TOML_EXPORTED_MEMBER_FUNCTION
    table& prune(bool recursive = true) & noexcept;

    /// \brief	Removes empty child arrays and tables (rvalue overload).
    ///
    /// \param recursive Should child arrays and tables themselves be pruned?
    ///
    /// \returns An rvalue reference to the table.
    table&& prune(bool recursive = true) && noexcept {
      return static_cast<toml::table&&>(this->prune(recursive));
    }

    /// \brief	Removes all key-value pairs from the table.
    TOML_EXPORTED_MEMBER_FUNCTION
    void clear() noexcept;

    /// @}

    /// \name Insertion and Emplacement
    /// @{

   private:
    /// \cond

    TOML_EXPORTED_MEMBER_FUNCTION
    map_iterator insert_with_hint(const_iterator, key&&, impl::node_ptr&&);

    /// \endcond

   public:
    /// \brief	Emplaces a new value at a specific key if one did not already exist.
    ///
    /// \tparam ValueType	toml::table, toml::array, or any native TOML value type.
    /// \tparam KeyType		A toml::key or any compatible string type.
    /// \tparam ValueArgs	Value constructor argument types.
    /// \param 	hint		Iterator to the position before which the new element will be emplaced.
    /// \param 	key			The key at which to emplace the new value.
    /// \param 	args		Arguments to forward to the value's constructor.
    ///
    /// \returns An iterator to the emplacement position (or the position of the value that
    /// prevented emplacement)
    ///
    /// \note This function has exactly the same semantics as
    /// [std::map::emplace_hint()](https://en.cppreference.com/w/cpp/container/map/emplace_hint).
    TOML_CONSTRAINED_TEMPLATE((is_key_or_convertible<KeyType&&> || impl::is_wide_string<KeyType>),
                              typename ValueType = void, typename KeyType, typename... ValueArgs)
    iterator emplace_hint(const_iterator hint, KeyType&& key, ValueArgs&&... args) {
      static_assert(!impl::is_wide_string<KeyType> || TOML_ENABLE_WINDOWS_COMPAT,
                    "Emplacement using wide-character keys is only supported on Windows with "
                    "TOML_ENABLE_WINDOWS_COMPAT enabled.");

      using raw_value_type = impl::remove_cvref<ValueType>;
      using value_type     = std::conditional_t<std::is_void_v<raw_value_type>,
                                                impl::emplaced_type_of<ValueArgs&&...>, raw_value_type>;

      if constexpr (impl::is_wide_string<KeyType>) {
#if TOML_ENABLE_WINDOWS_COMPAT
        return emplace_hint<value_type>(hint, impl::narrow(static_cast<KeyType&&>(key)),
                                        static_cast<ValueArgs&&>(args)...);
#else
        static_assert(impl::always_false<KeyType>, "Evaluated unreachable branch!");
#endif
      } else {
        static constexpr auto moving_node_ptr =
            std::is_same_v<value_type, impl::node_ptr>  //
            && sizeof...(ValueArgs) == 1u               //
            && impl::first_is_same<impl::node_ptr&&, ValueArgs&&...>;
        using unwrapped_type = impl::remove_cvref<impl::unwrap_node<value_type>>;

        static_assert(moving_node_ptr                                        //
                          || impl::is_native<unwrapped_type>                 //
                          || impl::is_one_of<unwrapped_type, table, array>,  //
                      "ValueType argument of table::emplace_hint() must be one "
                      "of:" TOML_SA_UNWRAPPED_NODE_TYPE_LIST);

        map_iterator ipos = insert_with_hint(hint, toml::key{static_cast<KeyType&&>(key)}, nullptr);

        // if second is nullptr then we successully claimed the key and inserted the empty sentinel,
        // so now we have to construct the actual value
        if (!ipos->second) {
          if constexpr (moving_node_ptr)
            ipos->second = std::move(static_cast<ValueArgs&&>(args)...);
          else {
#if TOML_COMPILER_HAS_EXCEPTIONS
            try {
#endif
              ipos->second.reset(
                  new impl::wrap_node<unwrapped_type>{static_cast<ValueArgs&&>(args)...});
#if TOML_COMPILER_HAS_EXCEPTIONS
            } catch (...) {
              erase(const_map_iterator{ipos});  // strong exception guarantee
              throw;
            }
#endif
          }
        }
        return iterator{ipos};
      }
    }

    /// \brief	Inserts a new value at a specific key if one did not already exist.
    ///
    /// \detail \godbolt{bMnW5r}
    ///
    /// \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 1 },
    ///		{ "b", 2 },
    ///		{ "c", 3 }
    ///	};
    /// std::cout << tbl << "\n";
    ///
    /// for (auto k : { "a", "d" })
    /// {
    ///		auto result = tbl.insert(k, 42);
    ///		std::cout << "inserted with key '"sv << k << "': "sv << result.second << "\n";
    /// }
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// a = 1
    /// b = 2
    /// c = 3
    ///
    /// inserted with key 'a': false
    /// inserted with key 'd': true
    /// a = 1
    /// b = 2
    /// c = 3
    /// d = 42
    /// \eout
    ///
    /// \tparam KeyType		A toml::key or any compatible string type.
    /// \tparam ValueType	toml::node, toml::node_view, toml::table, toml::array, or a native TOML
    /// value type 					(or a type promotable to one).
    /// \param 	key			The key at which to insert the new value.
    /// \param 	val			The new value to insert.
    /// \param	flags		Value flags to apply to new values.
    ///
    /// \returns	\conditional_return{Valid input}
    /// 			<ul>
    /// 				<li>An iterator to the insertion position (or the position of the value that
    /// prevented insertion) 				<li>A boolean indicating if the insertion was successful.
    /// 			</ul>
    ///				\conditional_return{Input is a null toml::node_view}
    /// 			`{ end(), false }`
    ///
    /// \attention The return value will always be `{ end(), false }` if the input value was an
    /// 		   null toml::node_view, because no insertion can take place. This is the only
    /// circumstance 		   in which this can occur.
    TOML_CONSTRAINED_TEMPLATE((is_key_or_convertible<KeyType&&> || impl::is_wide_string<KeyType>),
                              typename KeyType, typename ValueType)
    std::pair<iterator, bool> insert(KeyType&& key, ValueType&& val,
                                     value_flags flags = preserve_source_value_flags) {
      static_assert(!impl::is_wide_string<KeyType> || TOML_ENABLE_WINDOWS_COMPAT,
                    "Insertion using wide-character keys is only supported on Windows with "
                    "TOML_ENABLE_WINDOWS_COMPAT enabled.");

      if constexpr (is_node_view<ValueType>) {
        if (!val) return {end(), false};
      }

      if constexpr (impl::is_wide_string<KeyType>) {
#if TOML_ENABLE_WINDOWS_COMPAT
        return insert(impl::narrow(static_cast<KeyType&&>(key)), static_cast<ValueType&&>(val),
                      flags);
#else
        static_assert(impl::always_false<KeyType>, "Evaluated unreachable branch!");
#endif
      } else {
        const auto   key_view = std::string_view{key};
        map_iterator ipos     = get_lower_bound(key_view);
        if (ipos == map_.end() || ipos->first != key_view) {
          ipos = insert_with_hint(const_iterator{ipos}, toml::key{static_cast<KeyType&&>(key)},
                                  impl::make_node(static_cast<ValueType&&>(val), flags));
          return {iterator{ipos}, true};
        }
        return {iterator{ipos}, false};
      }
    }

    /// \brief	Inserts a series of key-value pairs into the table.
    ///
    /// \detail \godbolt{bzYcce}
    ///
    /// \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 1 },
    ///		{ "b", 2 },
    ///		{ "c", 3 }
    ///	};
    /// std::cout << tbl << "\n";
    ///
    /// auto kvps = std::array<std::pair<std::string, int>, 2>{{
    ///		{ "d", 42 },
    ///		{ "a", 43 } // won't be inserted, 'a' already exists
    ///	}};
    ///	tbl.insert(kvps.begin(), kvps.end());
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// a = 1
    /// b = 2
    /// c = 3
    ///
    /// a = 1
    /// b = 2
    /// c = 3
    /// d = 42
    /// \eout
    ///
    /// \tparam Iter	An InputIterator to a collection of key-value pairs.
    /// \param 	begin	An iterator to the first value in the input collection.
    /// \param 	end		An iterator to one-past-the-last value in the input collection.
    /// \param	flags		Value flags to apply to new values.
    ///
    /// \remarks This function is morally equivalent to calling `insert(key, value)` for each
    /// 		 key-value pair covered by the iterator range, so any values with keys already found in
    /// the 		 table will not be replaced.
    TOML_CONSTRAINED_TEMPLATE((!is_key_or_convertible<Iter> && !impl::is_wide_string<Iter>),
                              typename Iter)
    void insert(Iter begin, Iter end, value_flags flags = preserve_source_value_flags) {
      if (begin == end) return;
      for (auto it = begin; it != end; it++) {
        if constexpr (std::is_rvalue_reference_v<decltype(*it)>)
          insert(std::move((*it).first), std::move((*it).second), flags);
        else
          insert((*it).first, (*it).second, flags);
      }
    }

    /// \brief	Inserts or assigns a value at a specific key.
    ///
    /// \detail \godbolt{ddK563}
    ///
    /// \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 1 },
    ///		{ "b", 2 },
    ///		{ "c", 3 }
    ///	};
    /// std::cout << tbl << "\n";
    ///
    /// for (auto k : { "a", "d" })
    /// {
    ///		auto result = tbl.insert_or_assign(k, 42);
    ///		std::cout << "value at key '"sv << k
    ///			<< "' was "sv << (result.second ? "inserted"sv : "assigned"sv) << "\n";
    /// }
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// a = 1
    /// b = 2
    /// c = 3
    ///
    /// value at key 'a' was assigned
    /// value at key 'd' was inserted
    /// a = 42
    /// b = 2
    /// c = 3
    /// d = 42
    /// \eout
    ///
    /// \tparam KeyType		A toml::key or any compatible string type.
    /// \tparam ValueType	toml::node, toml::node_view, toml::table, toml::array, or a native TOML
    /// value type 					(or a type promotable to one).
    /// \param 	key			The key at which to insert or assign the value.
    /// \param 	val			The value to insert/assign.
    /// \param	flags		Value flags to apply to new values.
    ///
    /// \returns	\conditional_return{Valid input}
    /// 			<ul>
    /// 				<li>An iterator to the value's position
    /// 				<li>`true` if the value was inserted, `false` if it was assigned.
    /// 			</ul>
    /// 			\conditional_return{Input is a null toml::node_view}
    /// 			 `{ end(), false }`
    ///
    /// \attention The return value will always be `{ end(), false }` if the input value was
    /// 		   a null toml::node_view, because no insertion or assignment can take place.
    /// 		   This is the only circumstance in which this can occur.
    TOML_CONSTRAINED_TEMPLATE((is_key_or_convertible<KeyType&&> || impl::is_wide_string<KeyType>),
                              typename KeyType, typename ValueType)
    std::pair<iterator, bool> insert_or_assign(KeyType&& key, ValueType&& val,
                                               value_flags flags = preserve_source_value_flags) {
      static_assert(!impl::is_wide_string<KeyType> || TOML_ENABLE_WINDOWS_COMPAT,
                    "Insertion using wide-character keys is only supported on Windows with "
                    "TOML_ENABLE_WINDOWS_COMPAT enabled.");

      if constexpr (is_node_view<ValueType>) {
        if (!val) return {end(), false};
      }

      if constexpr (impl::is_wide_string<KeyType>) {
#if TOML_ENABLE_WINDOWS_COMPAT
        return insert_or_assign(impl::narrow(static_cast<KeyType&&>(key)),
                                static_cast<ValueType&&>(val), flags);
#else
        static_assert(impl::always_false<KeyType>, "Evaluated unreachable branch!");
#endif
      } else {
        const auto   key_view = std::string_view{key};
        map_iterator ipos     = get_lower_bound(key_view);
        if (ipos == map_.end() || ipos->first != key_view) {
          ipos = insert_with_hint(const_iterator{ipos}, toml::key{static_cast<KeyType&&>(key)},
                                  impl::make_node(static_cast<ValueType&&>(val), flags));
          return {iterator{ipos}, true};
        } else {
          (*ipos).second = impl::make_node(static_cast<ValueType&&>(val), flags);
          return {iterator{ipos}, false};
        }
      }
    }

    /// \brief	Emplaces a new value at a specific key if one did not already exist.
    ///
    /// \detail \cpp
    /// auto tbl = toml::table{
    ///		{ "a", 1 },
    ///		{ "b", 2 },
    ///		{ "c", 3 }
    ///	};
    /// std::cout << tbl << "\n";
    ///
    /// for (auto k : { "a", "d" })
    /// {
    ///		// add a string using std::string's substring constructor
    ///		auto result = tbl.emplace<std::string>(k, "this is not a drill"sv, 14, 5);
    ///		std::cout << "emplaced with key '"sv << k << "': "sv << result.second << "\n";
    /// }
    /// std::cout << tbl << "\n";
    /// \ecpp
    ///
    /// \out
    /// { a = 1, b = 2, c = 3 }
    /// emplaced with key 'a': false
    /// emplaced with key 'd': true
    /// { a = 1, b = 2, c = 3, d = "drill" }
    /// \eout
    ///
    /// \tparam ValueType	toml::table, toml::array, or any native TOML value type.
    /// \tparam KeyType		A toml::key or any compatible string type.
    /// \tparam ValueArgs	Value constructor argument types.
    /// \param 	key			The key at which to emplace the new value.
    /// \param 	args		Arguments to forward to the value's constructor.
    ///
    /// \returns A std::pair containing: <br>
    /// 		- An iterator to the emplacement position (or the position of the value that prevented
    /// emplacement)
    /// 		- A boolean indicating if the emplacement was successful.
    ///
    /// \remark There is no difference between insert() and emplace() for trivial value types
    /// (floats, ints, bools).
    TOML_CONSTRAINED_TEMPLATE((is_key_or_convertible<KeyType&&> || impl::is_wide_string<KeyType>),
                              typename ValueType = void, typename KeyType, typename... ValueArgs)
    std::pair<iterator, bool> emplace(KeyType&& key, ValueArgs&&... args) {
      static_assert(!impl::is_wide_string<KeyType> || TOML_ENABLE_WINDOWS_COMPAT,
                    "Emplacement using wide-character keys is only supported on Windows with "
                    "TOML_ENABLE_WINDOWS_COMPAT enabled.");

      using raw_value_type = impl::remove_cvref<ValueType>;
      using value_type     = std::conditional_t<std::is_void_v<raw_value_type>,
                                                impl::emplaced_type_of<ValueArgs&&...>, raw_value_type>;

      if constexpr (impl::is_wide_string<KeyType>) {
#if TOML_ENABLE_WINDOWS_COMPAT
        return emplace<value_type>(impl::narrow(static_cast<KeyType&&>(key)),
                                   static_cast<ValueArgs&&>(args)...);
#else
        static_assert(impl::always_false<KeyType>, "Evaluated unreachable branch!");
#endif
      } else {
        using unwrapped_type = impl::remove_cvref<impl::unwrap_node<value_type>>;
        static_assert(
            (impl::is_native<unwrapped_type> || impl::is_one_of<unwrapped_type, table, array>),
            "ValueType argument of table::emplace() must be one "
            "of:" TOML_SA_UNWRAPPED_NODE_TYPE_LIST);

        const auto key_view = std::string_view{key};
        auto       ipos     = get_lower_bound(key_view);
        if (ipos == map_.end() || ipos->first != key_view) {
          ipos = insert_with_hint(const_iterator{ipos}, toml::key{static_cast<KeyType&&>(key)},
                                  impl::node_ptr{new impl::wrap_node<unwrapped_type>{
                                      static_cast<ValueArgs&&>(args)...}});
          return {iterator{ipos}, true};
        }
        return {iterator{ipos}, false};
      }
    }

    /// @}

    /// \name Node views
    /// @{

    /// \cond
    using node::operator[];  // inherit operator[toml::path]
    /// \endcond

    /// \brief	Gets a node_view for the selected value.
    ///
    /// \param 	key The key used for the lookup.
    ///
    /// \returns	A view of the value at the given key if one existed, or an empty node view.
    ///
    /// \remarks std::map::operator[]'s behaviour of default-constructing a value at a key if it
    /// 		 didn't exist is a crazy bug factory so I've deliberately chosen not to emulate it.
    /// 		 <strong>This is not an error.</strong>
    ///
    /// \see toml::node_view
    TOML_NODISCARD
    node_view<node> operator[](std::string_view key) noexcept { return node_view<node>{get(key)}; }

    /// \brief	Gets a node_view for the selected value (const overload).
    ///
    /// \param 	key The key used for the lookup.
    ///
    /// \returns	A view of the value at the given key if one existed, or an empty node view.
    ///
    /// \remarks std::map::operator[]'s behaviour of default-constructing a value at a key if it
    /// 		 didn't exist is a crazy bug factory so I've deliberately chosen not to emulate it.
    /// 		 <strong>This is not an error.</strong>
    ///
    /// \see toml::node_view
    TOML_NODISCARD
    node_view<const node> operator[](std::string_view key) const noexcept {
      return node_view<const node>{get(key)};
    }

#if TOML_ENABLE_WINDOWS_COMPAT

    /// \brief	Gets a node_view for the selected value.
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \param 	key The key used for the lookup.
    ///
    /// \returns	A view of the value at the given key if one existed, or an empty node view.
    ///
    /// \remarks std::map::operator[]'s behaviour of default-constructing a value at a key if it
    /// 		 didn't exist is a crazy bug factory so I've deliberately chosen not to emulate it.
    /// 		 <strong>This is not an error.</strong>
    ///
    /// \see toml::node_view
    TOML_NODISCARD
    node_view<node> operator[](std::wstring_view key) { return node_view<node>{get(key)}; }

    /// \brief	Gets a node_view for the selected value (const overload).
    ///
    /// \availability This overload is only available when #TOML_ENABLE_WINDOWS_COMPAT is enabled.
    ///
    /// \param 	key The key used for the lookup.
    ///
    /// \returns	A view of the value at the given key if one existed, or an empty node view.
    ///
    /// \remarks std::map::operator[]'s behaviour of default-constructing a value at a key if it
    /// 		 didn't exist is a crazy bug factory so I've deliberately chosen not to emulate it.
    /// 		 <strong>This is not an error.</strong>
    ///
    /// \see toml::node_view
    TOML_NODISCARD
    node_view<const node> operator[](std::wstring_view key) const {
      return node_view<const node>{get(key)};
    }

#endif  // TOML_ENABLE_WINDOWS_COMPAT

    /// @}

    /// \name Equality
    /// @{

   private:
    /// \cond

    TOML_PURE_GETTER
    TOML_EXPORTED_STATIC_FUNCTION
    static bool TOML_CALLCONV equal(const table&, const table&) noexcept;

    /// \endcond
   public:
    /// \brief	Equality operator.
    ///
    /// \param 	lhs	The LHS table.
    /// \param 	rhs	The RHS table.
    ///
    /// \returns	True if the tables contained the same keys and map.
    TOML_NODISCARD
    friend bool operator==(const table& lhs, const table& rhs) noexcept { return equal(lhs, rhs); }

    /// \brief	Inequality operator.
    ///
    /// \param 	lhs	The LHS table.
    /// \param 	rhs	The RHS table.
    ///
    /// \returns	True if the tables did not contain the same keys and map.
    TOML_NODISCARD
    friend bool operator!=(const table& lhs, const table& rhs) noexcept { return !equal(lhs, rhs); }

    /// @}

#if TOML_ENABLE_FORMATTERS

    /// \brief	Prints the table out to a stream as formatted TOML.
    ///
    /// \availability This operator is only available when #TOML_ENABLE_FORMATTERS is enabled.
    friend std::ostream& operator<<(std::ostream& lhs, const table& rhs) {
      impl::print_to_stream(lhs, rhs);
      return lhs;
    }

#endif
  };
}
TOML_NAMESPACE_END;

#include "header_end.hpp"