tomlplusplus/include/toml++/toml_node_view.h
Mark Gillard 946a912cee added node::value() and node::value_or()
also:
- added `node_view::value`
- added relops for the date/time classes
- added `TOML_ALL_INLINE` and `TOML_IMPLEMENTATION` options
- fixed documentation header overflowing on narrow devices
2020-03-01 16:56:40 +02:00

386 lines
16 KiB
C++

#pragma once
#include "toml_table.h"
#include "toml_array.h"
#include "toml_value.h"
TOML_START
{
/// \brief A view of a node.
///
/// \detail A node_view is like a std::optional<toml::node> with lots of toml-specific stuff built-in.
/// It _may_ represent a node, and allows you to do many of the same operations that you'd do
/// on nodes directly, as well as easily traversing the node tree by creating
/// subviews (via node_view::operator[]). \cpp
///
/// auto tbl = toml::parse(R"(
///
/// title = "my hardware store"
///
/// [[products]]
/// name = "Hammer"
/// sku = 738594937
/// keywords = [ "hammer", "construction", "build" ]
///
/// [[products]]
/// name = "Nail"
/// sku = 284758393
/// color = "gray"
///
/// )"sv);
///
/// std::cout << tbl["title"] << std::endl;
/// std::cout << tbl["products"][0]["name"] << std::endl;
/// std::cout << tbl["products"][0]["keywords"] << std::endl;
/// std::cout << tbl["products"][0]["keywords"][2] << std::endl;
///
/// tbl["products"][0]["keywords"].as_array()->push_back("heavy");
/// std::cout << tbl["products"][0]["keywords"] << std::endl;
/// std::cout << "has product[2]: "sv << !!tbl["products"][2] << std::endl;
/// std::cout << "product[2]: "sv << tbl["products"][2] << std::endl;
/// \ecpp
///
/// \out
/// "my hardware store"
/// "Hammer"
/// [ "hammer", "construction", "build" ]
/// "build"
/// [ "hammer", "construction", "build", "heavy" ]
/// has product[2]: false
/// product[2]:
/// \eout
template <typename T>
class node_view final
{
public:
using viewed_type = T;
private:
friend class toml::table;
viewed_type* node_;
TOML_NODISCARD_CTOR
node_view(viewed_type* node) noexcept
: node_{ node }
{}
public:
/// \brief Returns true if the view references a node.
[[nodiscard]] explicit operator bool() const noexcept { return node_ != nullptr; }
/// \brief Returns the node that's being referenced by the view.
[[nodiscard]] viewed_type* get() noexcept { return node_; }
/// \brief Returns the node that's being referenced by the view (const overload).
[[nodiscard]] const viewed_type* get() const noexcept { return node_; }
/// \brief Returns the type identifier for the viewed node.
[[nodiscard]] node_type type() const noexcept { return node_ ? node_->type() : node_type::none; }
/// \brief Returns true if the viewed node is a toml::table.
[[nodiscard]] bool is_table() const noexcept { return node_ && node_->is_table(); }
/// \brief Returns true if the viewed node is a toml::array.
[[nodiscard]] bool is_array() const noexcept { return node_ && node_->is_array(); }
/// \brief Returns true if the viewed node is a toml::value<>.
[[nodiscard]] bool is_value() const noexcept { return node_ && node_->is_value(); }
/// \brief Returns true if the viewed node is a toml::value<string>.
[[nodiscard]] bool is_string() const noexcept { return node_ && node_->is_string(); }
/// \brief Returns true if the viewed node is a toml::value<int64_t>.
[[nodiscard]] bool is_integer() const noexcept { return node_ && node_->is_integer(); }
/// \brief Returns true if the viewed node is a toml::value<double>.
[[nodiscard]] bool is_floating_point() const noexcept { return node_ && node_->is_floating_point(); }
/// \brief Returns true if the viewed node is a toml::value<int64_t> or toml::value<double>.
[[nodiscard]] bool is_number() const noexcept { return node_ && node_->is_number(); }
/// \brief Returns true if the viewed node is a toml::value<bool>.
[[nodiscard]] bool is_boolean() const noexcept { return node_ && node_->is_boolean(); }
/// \brief Returns true if the viewed node is a toml::value<date>.
[[nodiscard]] bool is_date() const noexcept { return node_ && node_->is_date(); }
/// \brief Returns true if the viewed node is a toml::value<time>.
[[nodiscard]] bool is_time() const noexcept { return node_ && node_->is_time(); }
/// \brief Returns true if the viewed node is a toml::value<date_time>.
[[nodiscard]] bool is_date_time() const noexcept { return node_ && node_->is_date_time(); }
/// \brief Returns true if the viewed node is a toml::array that contains only tables.
[[nodiscard]] bool is_array_of_tables() const noexcept { return node_ && node_->is_array_of_tables(); }
/// \brief Checks if this view references a node of a specific type.
///
/// \tparam U A TOML node or value type.
///
/// \returns Returns true if the viewed node is an instance of the specified type.
///
/// \see toml::node::is()
template <typename U>
[[nodiscard]]
bool is() const noexcept
{
return node_ ? node_->template is<U>() : false;
}
/// \brief Gets a pointer to the viewed node as a more specific node type.
///
/// \tparam U The node type or TOML value type to cast to.
///
/// \returns A pointer to the node as the given type, or nullptr if it was a different type.
///
/// \see toml::node::as()
template <typename U>
[[nodiscard]]
auto as() noexcept
{
static_assert(
impl::is_value_or_node<impl::unwrapped<U>>,
"Template type parameter must be one of the basic value types, a toml::table, or a toml::array"
);
return node_ ? node_->template as<U>() : nullptr;
}
/// \brief Gets a pointer to the viewed node as a more specific node type (const overload).
template <typename U>
[[nodiscard]]
const impl::node_of<U>* as() const noexcept
{
static_assert(
impl::is_value_or_node<impl::unwrapped<U>>,
"Template type parameter must be one of the basic value types, a toml::table, or a toml::array"
);
return node_ ? node_->template as<U>() : nullptr;
}
/// \brief Returns a pointer to the viewed node as a toml::table, if it is one.
[[nodiscard]] auto as_table() noexcept { return as<table>(); }
/// \brief Returns a pointer to the viewed node as a toml::array, if it is one.
[[nodiscard]] auto as_array() noexcept { return as<array>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<string>, if it is one.
[[nodiscard]] auto as_string() noexcept { return as<string>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<int64_t>, if it is one.
[[nodiscard]] auto as_integer() noexcept { return as<int64_t>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<double>, if it is one.
[[nodiscard]] auto as_floating_point() noexcept { return as<double>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<bool>, if it is one.
[[nodiscard]] auto as_boolean() noexcept { return as<bool>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<date>, if it is one.
[[nodiscard]] auto as_date() noexcept { return as<date>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<time>, if it is one.
[[nodiscard]] auto as_time() noexcept { return as<time>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<date_time>, if it is one.
[[nodiscard]] auto as_date_time() noexcept { return as<date_time>(); }
/// \brief Returns a pointer to the viewed node as a toml::table, if it is one (const overload).
[[nodiscard]] const table* as_table() const noexcept { return as<table>(); }
/// \brief Returns a pointer to the viewed node as a toml::array, if it is one (const overload).
[[nodiscard]] const array* as_array() const noexcept { return as<array>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<string>, if it is one (const overload).
[[nodiscard]] const toml::value<string>* as_string() const noexcept { return as<string>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<int64_t>, if it is one (const overload).
[[nodiscard]] const toml::value<int64_t>* as_integer() const noexcept { return as<int64_t>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<double>, if it is one (const overload).
[[nodiscard]] const toml::value<double>* as_floating_point() const noexcept { return as<double>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<bool>, if it is one (const overload).
[[nodiscard]] const toml::value<bool>* as_boolean() const noexcept { return as<bool>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<date>, if it is one (const overload).
[[nodiscard]] const toml::value<date>* as_date() const noexcept { return as<date>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<time>, if it is one (const overload).
[[nodiscard]] const toml::value<time>* as_time() const noexcept { return as<time>(); }
/// \brief Returns a pointer to the viewed node as a toml::value<date_time>, if it is one (const overload).
[[nodiscard]] const toml::value<date_time>* as_date_time() const noexcept { return as<date_time>(); }
/// \brief Gets the raw value contained by the referenced node.
///
/// \tparam U One of the TOML value types. Can also be a string_view.
///
/// \returns The underlying value if the node was a value of the matching type (or convertible to it), or an empty optional.
///
/// \see node::value()
template <typename U>
[[nodiscard]] std::optional<U> value() const noexcept
{
if (node_)
return node_->template value<U>();
return {};
}
/// \brief Gets the raw value contained by the referenced node, or a default.
///
/// \tparam U Default value type. Must be (or be promotable to) one of the TOML value types.
/// \param default_value The default value to return if the view did not reference a node,
/// or if the node wasn't a value, wasn't the correct type, or no conversion was possible.
///
/// \returns The node's underlying value, or the default if the node wasn't a value, wasn't the
/// correct type, or no conversion was possible.
///
/// \see node::value_or()
template <typename U>
[[nodiscard]] auto value_or(U&& default_value) const noexcept
{
using return_type = decltype(node_->value_or(std::forward<U>(default_value)));
if (node_)
return node_->value_or(std::forward<U>(default_value));
return return_type{ std::forward<U>(default_value) };
}
private:
template <typename N, typename FUNC>
static decltype(auto) do_visit(N* node, FUNC&& visitor)
TOML_MAY_THROW_UNLESS(noexcept(std::declval<N*>()->visit(std::declval<FUNC&&>())))
{
using return_type = decltype(node->visit(std::forward<FUNC>(visitor)));
if (node)
return node->visit(std::forward<FUNC>(visitor));
if constexpr (!std::is_void_v<return_type>)
return return_type{};
}
template <typename FUNC, typename N>
static constexpr bool visit_is_nothrow =
noexcept(do_visit(std::declval<N*>(), std::declval<FUNC&&>()));
public:
/// \brief Invokes a visitor on the viewed node based on its concrete type.
///
/// \remarks Has no effect if the view does not reference a node.
///
/// \see node::visit()
template <typename FUNC>
decltype(auto) visit(FUNC&& visitor)
TOML_MAY_THROW_UNLESS(visit_is_nothrow<FUNC&&, viewed_type>)
{
return do_visit(node_, std::forward<FUNC>(visitor));
}
/// \brief Invokes a visitor on the viewed node based on its concrete type (const overload).
///
/// \remarks Has no effect if the view does not reference a node.
///
/// \see node::visit()
template <typename FUNC>
decltype(auto) visit(FUNC&& visitor) const
TOML_MAY_THROW_UNLESS(visit_is_nothrow<FUNC&&, const viewed_type>)
{
return do_visit(node_, std::forward<FUNC>(visitor));
}
/// \brief Returns true if the viewed node is a table with the same contents as RHS.
[[nodiscard]] friend bool operator == (const node_view& lhs, const table& rhs) noexcept
{
if (lhs.node_ == &rhs)
return true;
const auto tbl = lhs.as<table>();
return tbl && *tbl == rhs;
}
TOML_ASYMMETRICAL_EQUALITY_OPS(const node_view&, const table&, )
/// \brief Returns true if the viewed node is an array with the same contents as RHS.
[[nodiscard]] friend bool operator == (const node_view& lhs, const array& rhs) noexcept
{
if (lhs.node_ == &rhs)
return true;
const auto arr = lhs.as<array>();
return arr && *arr == rhs;
}
TOML_ASYMMETRICAL_EQUALITY_OPS(const node_view&, const array&, )
/// \brief Returns true if the viewed node is a value with the same value as RHS.
template <typename U>
[[nodiscard]] friend bool operator == (const node_view& lhs, const toml::value<U>& rhs) noexcept
{
if (lhs.node_ == &rhs)
return true;
const auto val = lhs.as<U>();
return val && *val == rhs;
}
TOML_ASYMMETRICAL_EQUALITY_OPS(const node_view&, const toml::value<U>&, template <typename U>)
/// \brief Returns true if the viewed node is a value with the same value as RHS.
template <typename U, typename = std::enable_if_t<impl::is_value_or_promotable<U>>>
[[nodiscard]] friend bool operator == (const node_view& lhs, const U& rhs) noexcept
{
const auto val = lhs.as<impl::promoted<U>>();
return val && *val == rhs;
}
TOML_ASYMMETRICAL_EQUALITY_OPS(
const node_view&,
const U&,
template <typename U, typename = std::enable_if_t<impl::is_value_or_promotable<U>>>
)
/// \brief Returns true if the viewed node is an array with the same contents as the RHS initializer list.
template <typename U>
[[nodiscard]] friend bool operator == (const node_view& lhs, const std::initializer_list<U>& rhs) noexcept
{
const auto arr = lhs.as<array>();
return arr && *arr == rhs;
}
TOML_ASYMMETRICAL_EQUALITY_OPS(const node_view&, const std::initializer_list<U>&, template <typename U>)
/// \brief Returns true if the viewed node is an array with the same contents as the RHS vector.
template <typename U>
[[nodiscard]] friend bool operator == (const node_view& lhs, const std::vector<U>& rhs) noexcept
{
const auto arr = lhs.as<array>();
return arr && *arr == rhs;
}
TOML_ASYMMETRICAL_EQUALITY_OPS(const node_view&, const std::vector<U>&, template <typename U>)
/// \brief Returns a view of the selected subnode.
///
/// \param key The key of the node to retrieve
///
/// \returns A view of the selected node if this node represented a table and it contained a
/// value at the given key, or an empty view.
[[nodiscard]] node_view<viewed_type> operator[] (string_view key) noexcept
{
if (auto tbl = this->as_table())
return { tbl->get(key) };
return { nullptr };
}
/// \brief Returns a view of the selected subnode.
///
/// \param index The index of the node to retrieve
///
/// \returns A view of the selected node if this node represented an array and it contained a
/// value at the given index, or an empty view.
[[nodiscard]] node_view<viewed_type> operator[] (size_t index) noexcept
{
if (auto tbl = this->as_array())
return { tbl->get(index) };
return { nullptr };
}
/// \brief Returns a view of the selected subnode (const overload).
[[nodiscard]] node_view<const viewed_type> operator[] (string_view key) const noexcept
{
if (auto tbl = this->as_table())
return { tbl->get(key) };
return { nullptr };
}
/// \brief Returns a view of the selected subnode (const overload).
[[nodiscard]] node_view<const viewed_type> operator[] (size_t index) const noexcept
{
if (auto tbl = this->as_array())
return { tbl->get(index) };
return { nullptr };
}
/// \brief Prints the viewed node out to a stream.
template <typename CHAR>
friend std::basic_ostream<CHAR>& operator << (std::basic_ostream<CHAR>& os, const node_view& nv) TOML_MAY_THROW
{
if (nv.node_)
{
nv.node_->visit([&os](const auto& n) TOML_MAY_THROW
{
os << n;
});
}
return os;
}
};
}
TOML_END