Class item

Defined in File item.hpp

Class Documentation

class item

item is a transient class that is used to pass data into rows but it also takes care of formatting data.

The class cif::item is often used implicitly when creating a row in a category using the emplace function.

cif::category cat("my-cat");
cat.emplace({
  { "item-1", 1 },                             // <- stores an item with value 1
  { "item-2", 1.0, 2 },                        // <- stores an item with value 1.00
  { "item-3", std::optional<int>() },          // <- stores an item with value ?
  { "item-4", std::make_optional<int>(42) },   // <- stores an item with value 42
  { "item-5" }                                 // <- stores an item with value .
});

std::cout << cat << '\n';

Will result in:

_my-cat.item-1 1
_my-cat.item-2 1.00
_my-cat.item-3 ?
_my-cat.item-4 42
_my-cat.item-5 .

Public Functions

item() = default: Default constructor, empty item.

inline item(std::string_view name): constructor for an item with name name and as content the character ‘.’, i.e. an inapplicable value.

inline item(std::string_view name, char value): constructor for an item with name name and as content a single character string with content value

template<typename T, std::enable_if_t<std::is_floating_point_v<T>, int> = 0> inline item(std::string_view name, const T &value, int precision): constructor for an item with name name and as content the formatted floating point value value with precision precision

template<typename T, std::enable_if_t<std::is_floating_point_v<T>, int> = 0> inline item(const std::string_view name, const T &value): constructor for an item with name name and as content a formatted floating point value value with so-called general formatting

template<typename T, std::enable_if_t<std::is_integral_v<T> and not std::is_same_v<T, bool>, int> = 0> inline item(const std::string_view name, const T &value): constructor for an item with name name and as content the formatted integral value value

template<typename T, std::enable_if_t<std::is_same_v<T, bool>, int> = 0> inline item(const std::string_view name, const T &value): constructor for an item with name name and as content the formatted boolean value value

inline item(const std::string_view name, std::string_view value): constructor for an item with name name and as content value value

template<typename T, std::enable_if_t<std::is_same_v<T, std::string>, int> = 0> inline item(const std::string_view name, T &&value): constructor for an item with name name and as content value value

template<typename T> inline item(const std::string_view name, const std::optional<T> &value): constructor for an item with name name and as content the optional value value

template<typename T, std::enable_if_t<std::is_floating_point_v<T>, int> = 0> inline item(std::string_view name, const std::optional<T> &value, int precision): constructor for an item with name name and as content the formatted floating point value value with precision precision

inline std::string_view name() const: Return the name of the item.

inline std::string_view value() const &: Return the value of the item.

inline std::string value() const &&: Return the value of the item.

inline void value(std::string_view v): replace the content of the stored value with v

inline bool empty() const: empty means either null or unknown

inline bool is_null() const: returns true if the item contains ‘.’

inline bool is_unknown() const: returns true if the item contains ‘?’

inline std::size_t length() const: the length of the value string

template<std::size_t N> inline decltype(auto) get() const: support for structured binding