documented row

8b2e02e1 · Maarten L. Hekkelman · 1addd2be · 8b2e02e1
Commit 8b2e02e1 authored Sep 06, 2023 by Maarten L. Hekkelman
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include/cif++/row.hpp
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--- a/include/cif++/row.hpp
+++ b/include/cif++/row.hpp
@@ -30,6 +30,51 @@
 #include <array>
+/**
+ * @file row.hpp
+ * 
+ * The class cif::row should be an opaque type. It is used to store the
+ * internal data per row in a category. You should use cif::row_handle
+ * to get access to the contents in a row.
+ * 
+ * One could think of rows as vectors of cif::item. But internally
+ * that's not the case.
+ * 
+ * You can access the values of stored items by name or index.
+ * The return value of operator[] is an cif::item_handle object.
+ * 
+ * @code {.cpp}
+ * cif::category &atom_site = my_db["atom_site"];
+ * cif::row_handle rh = atom_site.front();
+ * 
+ * // by name:
+ * std::string name = rh["label_atom_id"].as<std::string>();
+ * 
+ * // by index:
+ * uint16_t ix = atom_site.get_column_ix("label_atom_id");
+ * assert(rh[ix].as<std::string() == name);
+ * @endcode
+ * 
+ * There some template magic here to allow easy extracting of data
+ * from rows. This can be done using cif::tie e.g.:
+ * 
+ * @code {.cpp}
+ * std::string name;
+ * float x, y, z;
+ * 
+ * cif::tie(name, x, y, z) = rh.get("label_atom_id", "cartn_x", "cartn_y", "cartn_z");
+ * @endcode
+ * 
+ * However, a more modern way uses structured binding:
+ * 
+ * @code {.cpp}
+ * const auto &[name, x, y, z] = rh.get<std::string,float,float,float>("label_atom_id", "cartn_x", "cartn_y", "cartn_z");
+ * @endcode
+ * 
+ * 
+ * 
+ */
 namespace cif
 {
@@ -96,6 +141,8 @@ namespace detail
 } // namespace detail
+/// \brief similar to std::tie, assign values to each element in @a v from the 
+/// result of a get on a row_handle.
 template <typename... Ts>
 auto tie(Ts &...v)
 {
@@ -150,6 +197,7 @@ class row : public std::vector<item_value>
 class row_handle
 {
  public:
+	/** @cond */
 	friend struct item_handle;
 	friend class category;
 	friend class category_index;
@@ -163,79 +211,119 @@ class row_handle
 	row_handle &operator=(const row_handle &) = default;
 	row_handle &operator=(row_handle &&) = default;
+	/** @endcond */
+	/// \brief constructor taking a category @a cat and a row @a r
 	row_handle(const category &cat, const row &r)
 		: m_category(const_cast<category *>(&cat))
 		, m_row(const_cast<row *>(&r))
 	{
 	}
+	/// \brief return the category this row belongs to
 	const category &get_category() const
 	{
 		return *m_category;
 	}
+	/// \brief Return true if the row is empty or uninitialised
 	bool empty() const
 	{
 		return m_category == nullptr or m_row == nullptr;
 	}
+	/// \brief convenience method to test for empty()
 	explicit operator bool() const
 	{
 		return not empty();
 	}
+	/// \brief return a cif::item_handle to the item in column @a column_ix
 	item_handle operator[](uint16_t column_ix)
 	{
 		return empty() ? item_handle::s_null_item : item_handle(column_ix, *this);
 	}
+	/// \brief return a const cif::item_handle to the item in column @a column_ix
 	const item_handle operator[](uint16_t column_ix) const
 	{
 		return empty() ? item_handle::s_null_item : item_handle(column_ix, const_cast<row_handle &>(*this));
 	}
+	/// \brief return a cif::item_handle to the item in the column named @a column_name
 	item_handle operator[](std::string_view column_name)
 	{
 		return empty() ? item_handle::s_null_item : item_handle(add_column(column_name), *this);
 	}
+	/// \brief return a const cif::item_handle to the item in the column named @a column_name
 	const item_handle operator[](std::string_view column_name) const
 	{
 		return empty() ? item_handle::s_null_item : item_handle(get_column_ix(column_name), const_cast<row_handle &>(*this));
 	}
+	/// \brief Return an object that can be used in combination with cif::tie
+	/// to assign the values for the columns @a columns
 	template <typename... C>
 	auto get(C... columns) const
 	{
 		return detail::get_row_result<C...>(*this, { get_column_ix(columns)... });
 	}
+	/// \brief Return a tuple of values of types @a Ts for the columns @a columns
 	template <typename... Ts, typename... C, std::enable_if_t<sizeof...(Ts) == sizeof...(C) and sizeof...(C) != 1, int> = 0>
 	std::tuple<Ts...> get(C... columns) const
 	{
 		return detail::get_row_result<Ts...>(*this, { get_column_ix(columns)... });
 	}
+	/// \brief Get the value of column @a column cast to type @a T
 	template <typename T>
 	T get(const char *column) const
 	{
 		return operator[](get_column_ix(column)).template as<T>();
 	}
+	/// \brief assign each of the columns named in @a values to their respective value
 	void assign(const std::vector<item> &values)
 	{
 		for (auto &value : values)
 			assign(value, true);
 	}
+	/** \brief assign the value @a value to the column named @a name 
+	 * 
+	 * If updateLinked it true, linked records are updated as well.
+	 * That means that if column @name is part of the link definition
+	 * and the link results in a linked record in another category
+	 * this record in the linked category is updated as well.
+	 * 
+	 * If validate is true, which is default, the assigned value is
+	 * checked to see if it conforms to the rules defined in the dictionary
+	 */
 	void assign(std::string_view name, std::string_view value, bool updateLinked, bool validate = true)
 	{
 		assign(add_column(name), value, updateLinked, validate);
 	}
+	/** \brief assign the value @a value to column at index @a column
+	 * 
+	 * If updateLinked it true, linked records are updated as well.
+	 * That means that if column @a column is part of the link definition
+	 * and the link results in a linked record in another category
+	 * this record in the linked category is updated as well.
+	 * 
+	 * If validate is true, which is default, the assigned value is
+	 * checked to see if it conforms to the rules defined in the dictionary
+	 */
 	void assign(uint16_t column, std::string_view value, bool updateLinked, bool validate = true);
+	/// \brief compare two rows
 	bool operator==(const row_handle &rhs) const { return m_category == rhs.m_category and m_row == rhs.m_row; }
+	/// \brief compare two rows
 	bool operator!=(const row_handle &rhs) const { return m_category != rhs.m_category or m_row != rhs.m_row; }
  private:
@@ -267,9 +355,17 @@ class row_handle
 // --------------------------------------------------------------------
+/**
+ * @brief The class row_initializer is a list of cif::item's.
+ * 
+ * This class is used to construct new rows, it allows to
+ * group a list of item name and value pairs and pass it
+ * in one go to the constructing function.
+ */
 class row_initializer : public std::vector<item>
 {
  public:
+	/** @cond */
 	friend class category;
 	row_initializer() = default;
@@ -278,26 +374,38 @@ class row_initializer : public std::vector<item>
 	row_initializer &operator=(const row_initializer &) = default;
 	row_initializer &operator=(row_initializer &&) = default;
+	/** @endcond */
+	/// \brief constructor taking a std::initializer_list of items
 	row_initializer(std::initializer_list<item> items)
 		: std::vector<item>(items)
 	{
 	}
+	/// \brief constructor taking a range of items
 	template <typename ItemIter, std::enable_if_t<std::is_same_v<typename ItemIter::value_type, item>, int> = 0>
 	row_initializer(ItemIter b, ItemIter e)
 		: std::vector<item>(b, e)
 	{
 	}
+	/// \brief constructor taking the values of an existing row
 	row_initializer(row_handle rh);
+	/// \brief set the value for item name @a name to @a value
 	void set_value(std::string_view name, std::string_view value);
+	/// \brief set the value for item based on @a i
 	void set_value(const item &i)
 	{
 		set_value(i.name(), i.value());
 	}
+	/// \brief set the value for item name @a name to @a value, but only if the item did not have a value already
 	void set_value_if_empty(std::string_view name, std::string_view value);
+	/// \brief set the value for item @a i, but only if the item did not have a value already
 	void set_value_if_empty(const item &i)
 	{
 		set_value_if_empty(i.name(), i.value());