template <typename ValueType>
toml::value class

A TOML value.

Template parameters
ValueType

The value's native TOML data type. Can be one of:

Base classes

class node
A TOML node.

Public types

using value_arg = /* ... */
A type alias for 'value arguments'.
using value_type = ValueType
The value's underlying data type.

Constructors, destructors, conversion operators

template <typename... Args>
value(Args && ... args) explicit noexcept(…)
Constructs a toml value.
value(const value& other) noexcept
Copy constructor.
value(const value& other, value_flags flags) noexcept
Copy constructor with flags override.
value(value&& other) noexcept
Move constructor.
value(value&& other, value_flags flags) noexcept
Move constructor with flags override.

Public functions

auto operator=(const value& rhs) →  value& noexcept
Copy-assignment operator.
auto operator=(value&& rhs) →  value& noexcept
Move-assignment operator.
auto operator=(value_arg rhs) →  value& noexcept
Value-assignment operator.

Equality and Comparison

template <typename T>
auto operator!=(const value& lhs, const value<T>& rhs) →  bool noexcept
Inequality operator.
auto operator<(const value& lhs, value_arg rhs) →  bool noexcept
Value less-than operator.
auto operator<(value_arg lhs, const value& rhs) →  bool noexcept
Value less-than operator.
template <typename T>
auto operator<(const value& lhs, const value<T>& rhs) →  bool noexcept
Less-than operator.
auto operator<=(const value& lhs, value_arg rhs) →  bool noexcept
Value less-than-or-equal-to operator.
auto operator<=(value_arg lhs, const value& rhs) →  bool noexcept
Value less-than-or-equal-to operator.
template <typename T>
auto operator<=(const value& lhs, const value<T>& rhs) →  bool noexcept
Less-than-or-equal-to operator.
auto operator==(const value& lhs, value_arg rhs) →  bool noexcept
Value equality operator.
template <typename T>
auto operator==(const value& lhs, const value<T>& rhs) →  bool noexcept
Equality operator.
auto operator>(const value& lhs, value_arg rhs) →  bool noexcept
Value greater-than operator.
auto operator>(value_arg lhs, const value& rhs) →  bool noexcept
Value greater-than operator.
template <typename T>
auto operator>(const value& lhs, const value<T>& rhs) →  bool noexcept
Greater-than operator.
auto operator>=(const value& lhs, value_arg rhs) →  bool noexcept
Value greater-than-or-equal-to operator.
auto operator>=(value_arg lhs, const value& rhs) →  bool noexcept
Value greater-than-or-equal-to operator.
template <typename T>
auto operator>=(const value& lhs, const value<T>& rhs) →  bool noexcept
Greater-than-or-equal-to operator.

Metadata

auto flags() const →  value_flags noexcept
Returns the metadata flags associated with this value.
auto flags(value_flags new_flags) →  value& noexcept
Sets the metadata flags associated with this value.
auto source() const →  const source_region& noexcept
Returns the source region responsible for generating this node during parsing.

Node views

auto at_path(std::string_view path) →  node_view<node> noexcept
Returns a view of the subnode matching a fully-qualified "TOML path".
auto at_path(std::string_view path) const →  node_view<const node> noexcept
Returns a const view of the subnode matching a fully-qualified "TOML path".
auto at_path(const toml::path& path) →  node_view<node> noexcept
Returns a view of the subnode matching a fully-qualified "TOML path".
auto at_path(const toml::path& path) const →  node_view<const node> noexcept
Returns a const view of the subnode matching a fully-qualified "TOML path".
auto at_path(std::wstring_view path) →  node_view<node>
Returns a view of the subnode matching a fully-qualified "TOML path".
auto at_path(std::wstring_view path) const →  node_view<const node>
Returns a const view of the subnode matching a fully-qualified "TOML path".
operator node_view<const node>() const explicit noexcept
Creates a node_view pointing to this node (const overload).
operator node_view<node>() explicit noexcept
Creates a node_view pointing to this node.
auto operator[](const toml::path& path) →  node_view<node> noexcept
Returns a const view of the subnode matching a fully-qualified "TOML path".
auto operator[](const toml::path& path) const →  node_view<const node> noexcept
Returns a const view of the subnode matching a fully-qualified "TOML path".

Type casts

template <typename T>
auto as() →  impl::wrap_node<T>* noexcept
Gets a pointer to the node as a more specific node type.
template <typename T>
auto as() const →  const impl::wrap_node<T>* noexcept
Gets a pointer to the node as a more specific node type (const overload).
auto as_array() →  array* final noexcept
Returns nullptr.
auto as_array() const →  const array* final noexcept
Returns nullptr.
auto as_boolean() →  value<bool>* final noexcept
Returns a pointer to the value if it is a value<bool>, otherwise nullptr.
auto as_boolean() const →  const value<bool>* final noexcept
Returns a const-qualified pointer to the value if it is a value<bool>, otherwise nullptr.
auto as_date() →  value<date>* final noexcept
Returns a pointer to the value if it is a value<date>, otherwise nullptr.
auto as_date() const →  const value<date>* final noexcept
Returns a const-qualified pointer to the value if it is a value<date>, otherwise nullptr.
auto as_date_time() →  value<date_time>* final noexcept
Returns a pointer to the value if it is a value<date_time>, otherwise nullptr.
auto as_date_time() const →  const value<date_time>* final noexcept
Returns a const-qualified pointer to the value if it is a value<date_time>, otherwise nullptr.
auto as_floating_point() →  value<double>* final noexcept
Returns a pointer to the value if it is a value<double>, otherwise nullptr.
auto as_floating_point() const →  const value<double>* final noexcept
Returns a const-qualified pointer to the value if it is a value<double>, otherwise nullptr.
auto as_integer() →  value<int64_t>* final noexcept
Returns a pointer to the value if it is a value<int64_t>, otherwise nullptr.
auto as_integer() const →  const value<int64_t>* final noexcept
Returns a const-qualified pointer to the value if it is a value<int64_t>, otherwise nullptr.
auto as_string() →  value<std::string>* final noexcept
Returns a pointer to the value if it is a value<std::string>, otherwise nullptr.
auto as_string() const →  const value<std::string>* final noexcept
Returns a const-qualified pointer to the value if it is a value<std::string>, otherwise nullptr.
auto as_table() →  table* final noexcept
Returns nullptr.
auto as_table() const →  const table* final noexcept
Returns nullptr.
auto as_time() →  value<time>* final noexcept
Returns a pointer to the value if it is a value<time>, otherwise nullptr.
auto as_time() const →  const value<time>* final noexcept
Returns a const-qualified pointer to the value if it is a value<time>, otherwise nullptr.

Type checks

template <typename T>
auto is() const →  bool noexcept
Checks if a node is a specific type.
auto is_array() const →  bool final noexcept
Returns false.
auto is_array_of_tables() const →  bool final noexcept
Returns false.
auto is_boolean() const →  bool final noexcept
Returns true if the value_type is bool.
auto is_date() const →  bool final noexcept
Returns true if the value_type is toml::date.
auto is_date_time() const →  bool final noexcept
Returns true if the value_type is toml_date_time.
auto is_floating_point() const →  bool final noexcept
Returns true if the value_type is double.
auto is_homogeneous(node_type ntype) const →  bool final noexcept
Checks if the node contains values/elements of only one type.
auto is_homogeneous(node_type ntype, node*& first_nonmatch) →  bool final noexcept
Checks if a node contains values/elements of only one type.
auto is_homogeneous(node_type ntype, const node*& first_nonmatch) const →  bool final noexcept
Checks if a node contains values/elements of only one type (const overload).
template <typename ElemType = void>
auto is_homogeneous() const →  bool noexcept
Checks if the node contains values/elements of only one type.
auto is_integer() const →  bool final noexcept
Returns true if the value_type is int64_t.
auto is_number() const →  bool final noexcept
Returns true if the value_type is int64_t or double.
auto is_string() const →  bool final noexcept
Returns true if the value_type is std::string.
auto is_table() const →  bool final noexcept
Returns false.
auto is_time() const →  bool final noexcept
Returns true if the value_type is toml::time.
auto is_value() const →  bool final noexcept
Returns true.
auto type() const →  node_type final noexcept
Returns the value's node type identifier.

Value retrieval

auto get() & →  value_type& noexcept
Returns a reference to the underlying value.
auto get() && →  value_type&& noexcept
Returns a reference to the underlying value (rvalue overload).
auto get() const & →  const value_type& noexcept
Returns a reference to the underlying value (const overload).
auto get() const && →  const value_type&& noexcept
Returns a reference to the underlying value (const rvalue overload).
operator const value_type&() const & explicit noexcept
Returns a reference to the underlying value (const overload).
operator const value_type&&() && explicit noexcept
Returns a reference to the underlying value (const rvalue overload).
operator value_type&() & explicit noexcept
Returns a reference to the underlying value.
operator value_type&&() && explicit noexcept
Returns a reference to the underlying value (rvalue overload).
auto operator*() & →  value_type& noexcept
Returns a reference to the underlying value.
auto operator*() && →  value_type&& noexcept
Returns a reference to the underlying value (rvalue overload).
auto operator*() const & →  const value_type& noexcept
Returns a reference to the underlying value (const overload).
auto operator*() const && →  const value_type&& noexcept
Returns a reference to the underlying value (const rvalue overload).
auto operator->() →  value_type* noexcept
Returns a pointer to the underlying value.
auto operator->() const →  const value_type* noexcept
Returns a pointer to the underlying value (const overload).
template <typename T>
auto ref() & →  decltype(auto) noexcept
Gets a raw reference to a node's underlying data.
template <typename T>
auto ref() && →  decltype(auto) noexcept
Gets a raw reference to a node's underlying data (rvalue overload).
template <typename T>
auto ref() const & →  decltype(auto) noexcept
Gets a raw reference to a node's underlying data (const lvalue overload).
template <typename T>
auto ref() const && →  decltype(auto) noexcept
Gets a raw reference to a node's underlying data (const rvalue overload).
template <typename T>
auto value() const →  optional<T> noexcept(…)
Gets the value contained by this node.
template <typename T>
auto value_exact() const →  optional<T> noexcept(…)
Gets the value contained by this node.
template <typename T>
auto value_or(T&& default_value) const →  auto noexcept(…)
Gets the raw value contained by this node, or a default.

Visitation

template <typename Func>
auto visit(Func&& visitor) & →  decltype(auto) noexcept(…)
Invokes a visitor on the node based on the node's concrete type.
template <typename Func>
auto visit(Func&& visitor) && →  decltype(auto) noexcept(…)
Invokes a visitor on the node based on the node's concrete type (rvalue overload).
template <typename Func>
auto visit(Func&& visitor) const & →  decltype(auto) noexcept(…)
Invokes a visitor on the node based on the node's concrete type (const lvalue overload).
template <typename Func>
auto visit(Func&& visitor) const && →  decltype(auto) noexcept(…)
Invokes a visitor on the node based on the node's concrete type (const rvalue overload).

Friends

auto operator<<(std::ostream& lhs, const value& rhs) →  std::ostream&
Prints the value out to a stream as formatted TOML.

Typedef documentation

template <typename ValueType>
using toml::value::value_arg = /* ... */

A type alias for 'value arguments'.

This differs according to the value's type argument:

  • ints, floats, booleans: value_type
  • strings: string_view
  • everything else: const value_type&

Function documentation

template <typename ValueType>
template <typename... Args>
toml::value::value(Args && ... args) explicit noexcept(…)

Constructs a toml value.

Template parameters
Args Constructor argument types.
Parameters
args Arguments to forward to the internal value's constructor.

template <typename ValueType>
template <typename T>
bool toml::value::operator!=(const value& lhs, const value<T>& rhs) noexcept

Inequality operator.

Parameters
lhs The LHS value.
rhs The RHS value.
Returns True if the values were not of the same type, or did not contain the same value.

template <typename ValueType>
template <typename T>
bool toml::value::operator<(const value& lhs, const value<T>& rhs) noexcept

Less-than operator.

Parameters
lhs The LHS toml::value.
rhs The RHS toml::value.
Returns Same value types: lhs.get() < rhs.get()Different value types: lhs.type() < rhs.type()

template <typename ValueType>
template <typename T>
bool toml::value::operator<=(const value& lhs, const value<T>& rhs) noexcept

Less-than-or-equal-to operator.

Parameters
lhs The LHS toml::value.
rhs The RHS toml::value.
Returns Same value types: lhs.get() <= rhs.get()Different value types: lhs.type() <= rhs.type()

template <typename ValueType>
template <typename T>
bool toml::value::operator==(const value& lhs, const value<T>& rhs) noexcept

Equality operator.

Parameters
lhs The LHS value.
rhs The RHS value.
Returns True if the values were of the same type and contained the same value.

template <typename ValueType>
template <typename T>
bool toml::value::operator>(const value& lhs, const value<T>& rhs) noexcept

Greater-than operator.

Parameters
lhs The LHS toml::value.
rhs The RHS toml::value.
Returns Same value types: lhs.get() > rhs.get()Different value types: lhs.type() > rhs.type()

template <typename ValueType>
template <typename T>
bool toml::value::operator>=(const value& lhs, const value<T>& rhs) noexcept

Greater-than-or-equal-to operator.

Parameters
lhs The LHS toml::value.
rhs The RHS toml::value.
Returns Same value types: lhs.get() >= rhs.get()Different value types: lhs.type() >= rhs.type()

template <typename ValueType>
value& toml::value::flags(value_flags new_flags) noexcept

Sets the metadata flags associated with this value.

Returns A reference to the value object.

template <typename ValueType>
bool toml::value::is_homogeneous(node_type ntype) const final noexcept

Checks if the node contains values/elements of only one type.

Parameters
ntype A TOML node type.
toml::node_type::none: "is every element the same type?" Anything else: "is every element one of these?"
Returns True if the node was homogeneous. 
auto arr = toml::array{ 1, 2, 3 };
std::cout << "homogenous: "sv << arr.is_homogeneous(toml::node_type::none) << "\n";
std::cout << "all floats: "sv << arr.is_homogeneous(toml::node_type::floating_point) << "\n";
std::cout << "all arrays: "sv << arr.is_homogeneous(toml::node_type::array) << "\n";
std::cout << "all ints:   "sv << arr.is_homogeneous(toml::node_type::integer) << "\n";
homogeneous: true
all floats:  false
all arrays:  false
all ints:    true

template <typename ValueType>
bool toml::value::is_homogeneous(node_type ntype, node*& first_nonmatch) final noexcept

Checks if a node contains values/elements of only one type.

Parameters
ntype A TOML node type.
toml::node_type::none: "is every element the same type?" Anything else: "is every element one of these?"
first_nonmatch Reference to a pointer in which the address of the first non-matching element will be stored if the return value is false.
Returns True if the node was homogeneous. 
auto cfg = toml::parse("arr = [ 1, 2, 3, 4.0 ]");
toml::array& arr = *cfg["arr"].as_array();

toml::node* nonmatch{};
if (arr.is_homogeneous(toml::node_type::integer, nonmatch))
    std::cout << "array was homogeneous"sv << "\n";
else
    std::cout << "array was not homogeneous!\n"
    << "first non-match was a "sv << nonmatch->type() << " at " << nonmatch->source() << "\n";
array was not homogeneous!
first non-match was a floating-point at line 1, column 18

template <typename ValueType>
node_type toml::value::type() const final noexcept

Returns the value's node type identifier.

Returns

One of:

template <typename ValueType>
value_type* toml::value::operator->() noexcept

Returns a pointer to the underlying value.

template <typename ValueType>
const value_type* toml::value::operator->() const noexcept

Returns a pointer to the underlying value (const overload).

template <typename ValueType>
std::ostream& operator<<(std::ostream& lhs, const value& rhs)

Prints the value out to a stream as formatted TOML.