Merge branch 'develop' into trunk

cif::file constructors

.gitignore

@@ -11,4 +11,5 @@ Testing/
 include/cif++/exports.hpp
 docs/api
 docs/conf.py
-build_ci/
+build_ci/
+data/components.cif

CMakeLists.txt

@@ -27,7 +27,7 @@ cmake_minimum_required(VERSION 3.16)
 # set the project name
 project(
 	libcifpp
-	VERSION 6.1.0
+	VERSION 7.0.1
 	LANGUAGES CXX)
 
 list(PREPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
@@ -304,34 +304,45 @@ set(project_sources
 )
 
 set(project_headers
-	${PROJECT_SOURCE_DIR}/include/cif++.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/utilities.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/item.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/datablock.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/file.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/validate.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/iterator.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/parser.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/forward_decl.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/dictionary_parser.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/condition.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/category.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/row.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/atom_type.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/compound.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/point.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/symmetry.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/model.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/pdb.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/pdb/cif2pdb.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/pdb/io.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/pdb/pdb2cif.hpp
-	${PROJECT_SOURCE_DIR}/include/cif++/pdb/tls.hpp)
+	include/cif++.hpp
+	include/cif++/utilities.hpp
+	include/cif++/item.hpp
+	include/cif++/datablock.hpp
+	include/cif++/file.hpp
+	include/cif++/validate.hpp
+	include/cif++/iterator.hpp
+	include/cif++/parser.hpp
+	include/cif++/forward_decl.hpp
+	include/cif++/dictionary_parser.hpp
+	include/cif++/condition.hpp
+	include/cif++/category.hpp
+	include/cif++/row.hpp
+	include/cif++/atom_type.hpp
+	include/cif++/compound.hpp
+	include/cif++/point.hpp
+	include/cif++/symmetry.hpp
+	include/cif++/model.hpp
+	include/cif++/pdb.hpp
+	include/cif++/pdb/cif2pdb.hpp
+	include/cif++/pdb/io.hpp
+	include/cif++/pdb/pdb2cif.hpp
+	include/cif++/pdb/tls.hpp)
 
-add_library(cifpp ${project_sources} ${project_headers}
-	${PROJECT_SOURCE_DIR}/src/symop_table_data.hpp)
+add_library(cifpp STATIC)
 add_library(cifpp::cifpp ALIAS cifpp)
 
+target_sources(cifpp
+	PRIVATE ${project_sources}
+	${PROJECT_SOURCE_DIR}/src/symop_table_data.hpp
+	PUBLIC
+	FILE_SET cifpp_headers TYPE HEADERS
+	BASE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/include
+	FILES ${project_headers}
+)
+
+# The code now really requires C++20
+target_compile_features(cifpp PUBLIC cxx_std_20)
+
 set(CMAKE_DEBUG_POSTFIX d)
 set_target_properties(cifpp PROPERTIES DEBUG_POSTFIX "d")
 
@@ -452,14 +463,9 @@ else()
 endif()
 
 # Install rules
-install(
-	TARGETS cifpp
-	EXPORT cifpp-targets
-	ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
-	LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-	RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
-	INCLUDES
-	DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+install(TARGETS cifpp
+	EXPORT cifpp
+	FILE_SET cifpp_headers DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
 
 if(MSVC AND BUILD_SHARED_LIBS)
 	install(
@@ -479,23 +485,12 @@ if(OLD_CONFIG_FILES)
 	install(CODE "file(REMOVE ${OLD_CONFIG_FILES})")
 endif()
 
-install(
-	EXPORT cifpp-targets
-	FILE "cifpp-targets.cmake"
+install(EXPORT cifpp
 	NAMESPACE cifpp::
-	DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/cifpp)
+	FILE "cifpp-targets.cmake"
+	DESTINATION lib/cmake/cifpp)
 
-install(
-	DIRECTORY include/cif++
-	DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-	COMPONENT Devel)
-
-install(
-	FILES include/cif++.hpp
-	DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
-	COMPONENT Devel)
-
-if(CIFPP_DATA_DIR)
+if(CIFPP_DATA_DIR AND CIFPP_DOWNLOAD_CCD)
 	install(
 		FILES ${PROJECT_SOURCE_DIR}/rsrc/mmcif_ddl.dic
 		${PROJECT_SOURCE_DIR}/rsrc/mmcif_pdbx.dic
@@ -503,7 +498,7 @@ if(CIFPP_DATA_DIR)
 		DESTINATION ${CIFPP_DATA_DIR})
 endif()
 
-if(CIFPP_CACHE_DIR)
+if(CIFPP_CACHE_DIR AND CIFPP_DOWNLOAD_CCD)
 	install(
 		FILES ${PROJECT_SOURCE_DIR}/rsrc/mmcif_ddl.dic
 		${PROJECT_SOURCE_DIR}/rsrc/mmcif_pdbx.dic
@@ -515,14 +510,13 @@ set(CONFIG_TEMPLATE_FILE ${PROJECT_SOURCE_DIR}/cmake/cifpp-config.cmake.in)
 
 configure_package_config_file(
 	${CONFIG_TEMPLATE_FILE} ${CMAKE_CURRENT_BINARY_DIR}/cifpp/cifpp-config.cmake
-	INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/cifpp
+	INSTALL_DESTINATION lib/cmake/cifpp
 	PATH_VARS CIFPP_DATA_DIR)
 
 install(
 	FILES "${CMAKE_CURRENT_BINARY_DIR}/cifpp/cifpp-config.cmake"
 	"${CMAKE_CURRENT_BINARY_DIR}/cifpp/cifpp-config-version.cmake"
-	DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/cifpp
-	COMPONENT Devel)
+	DESTINATION lib/cmake/cifpp)
 
 set_target_properties(
 	cifpp
@@ -546,55 +540,7 @@ if(NOT PROJECT_IS_TOP_LEVEL)
 endif()
 
 if(BUILD_TESTING)
-	# We're using the older version 2 of Catch2
-	FetchContent_Declare(
-		Catch2
-		GIT_REPOSITORY https://github.com/catchorg/Catch2.git
-		GIT_TAG v2.13.9)
-
-	FetchContent_MakeAvailable(Catch2)
-
-	list(
-		APPEND
-		CIFPP_tests
-		unit-v2
-		unit-3d
-		format
-		model
-		rename-compound
-		sugar
-		spinner
-		validate-pdbx)
-
-	foreach(CIFPP_TEST IN LISTS CIFPP_tests)
-		set(CIFPP_TEST "${CIFPP_TEST}-test")
-		set(CIFPP_TEST_SOURCE "${CMAKE_CURRENT_SOURCE_DIR}/test/${CIFPP_TEST}.cpp")
-
-		add_executable(
-			${CIFPP_TEST} ${CIFPP_TEST_SOURCE}
-			"${CMAKE_CURRENT_SOURCE_DIR}/test/test-main.cpp")
-
-		target_link_libraries(${CIFPP_TEST} PRIVATE Threads::Threads cifpp::cifpp
-			Catch2::Catch2)
-		target_include_directories(${CIFPP_TEST} PRIVATE "${EIGEN_INCLUDE_DIR}")
-
-		if(MSVC)
-			# Specify unwind semantics so that MSVC knowns how to handle exceptions
-			target_compile_options(${CIFPP_TEST} PRIVATE /EHsc)
-		endif()
-
-		add_custom_target(
-			"run-${CIFPP_TEST}"
-			DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/Run${CIFPP_TEST}.touch ${CIFPP_TEST})
-
-		add_custom_command(
-			OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/Run${CIFPP_TEST}.touch
-			COMMAND $<TARGET_FILE:${CIFPP_TEST}> --data-dir
-			${CMAKE_CURRENT_SOURCE_DIR}/test)
-
-		add_test(NAME ${CIFPP_TEST} COMMAND $<TARGET_FILE:${CIFPP_TEST}> --data-dir
-			${CMAKE_CURRENT_SOURCE_DIR}/test)
-	endforeach()
+	add_subdirectory(test)
 endif()
 
 # Optionally install the update scripts for CCD and dictionary files

changelog

@@ -1,3 +1,18 @@
+Version 7.0.1
+- Various reconstruction fixes
+- category order in output fixed
+- better implementation of constructors for file, datablock and category
+- small optimisation in iterator
+
+Version 7.0.0
+- Renaming many methods and parameters to be more
+  consistent with the mmCIF dictionaries.
+  (Most notably, item used to be called column or
+  tag sometimes).
+- validation_error is now a std::system_error error
+  value. The exception is gone.
+- Added repairSequenceInfo to repair invalid files
+
 Version 6.1.0
 - Add formula weight to entity in pdb2cif
 - Change order of categories inside a datablock to match order in file

include/cif++/category.hpp

@@ -31,22 +31,22 @@
 #include "cif++/condition.hpp"
 #include "cif++/iterator.hpp"
 #include "cif++/row.hpp"
-#include "cif++/validate.hpp"
 #include "cif++/text.hpp"
+#include "cif++/validate.hpp"
 
 #include <array>
 
 /** \file category.hpp
-  * Documentation for the cif::category class
-  *
-  * The category class should meet the requirements of Container and
-  * SequenceContainer.
-  * 
-  * TODO: implement all of:
-  * https://en.cppreference.com/w/cpp/named_req/Container
-  * https://en.cppreference.com/w/cpp/named_req/SequenceContainer
-  * and more?
-  */
+ * Documentation for the cif::category class
+ *
+ * The category class should meet the requirements of Container and
+ * SequenceContainer.
+ *
+ * TODO: implement all of:
+ * https://en.cppreference.com/w/cpp/named_req/Container
+ * https://en.cppreference.com/w/cpp/named_req/SequenceContainer
+ * and more?
+ */
 
 namespace cif
 {
@@ -61,23 +61,43 @@ namespace cif
 class duplicate_key_error : public std::runtime_error
 {
   public:
-    /**
-     * @brief Construct a new duplicate key error object
-     */
+	/**
+	 * @brief Construct a new duplicate key error object
+	 */
 	duplicate_key_error(const std::string &msg)
 		: std::runtime_error(msg)
 	{
 	}
 };
 
+/// @brief A missing_key_error is thrown when an attempt is made
+/// to create an index when one of the key items is missing.
+class missing_key_error : public std::runtime_error
+{
+  public:
+	/**
+	 * @brief Construct a new duplicate key error object
+	 */
+	missing_key_error(const std::string &msg, const std::string &key)
+		: std::runtime_error(msg)
+		, m_key(key)
+	{
+	}
+
+	const std::string &get_key() const noexcept { return m_key; }
+
+  private:
+	std::string m_key;
+};
+
 /// @brief A multiple_results_error is throw when you request a single
 /// row using a query but the query contains more than exactly one row.
 class multiple_results_error : public std::runtime_error
 {
   public:
-    /**
-     * @brief Construct a new multiple results error object
-     */
+	/**
+	 * @brief Construct a new multiple results error object
+	 */
 	multiple_results_error()
 		: std::runtime_error("query should have returned exactly one row")
 	{
@@ -121,23 +141,39 @@ class category
 
 	/// \endcond
 
-	category() = default;                     ///< Default constructor
-	category(std::string_view name);          ///< Constructor taking a \a name
-	category(const category &rhs);            ///< Copy constructor
-	category(category &&rhs);                 ///< Move constructor
-	category &operator=(const category &rhs); ///< Copy assignement operator
-	category &operator=(category &&rhs);      ///< Move assignement operator
+	category() = default;            ///< Default constructor
+	category(std::string_view name); ///< Constructor taking a \a name
+	category(const category &rhs);   ///< Copy constructor
+
+	category(category &&rhs) noexcept ///< Move constructor
+	{
+		swap(*this, rhs);
+	}
+
+	category &operator=(category rhs) ///< assignement operator
+	{
+		swap(*this, rhs);
+		return *this;
+	}
 
 	/// @brief Destructor
 	/// @note Please note that the destructor is not virtual. It is assumed that
 	/// you will not derive from this class.
 	~category();
 
+	friend void swap(category &a, category &b) noexcept;
+
 	// --------------------------------------------------------------------
 
 	const std::string &name() const { return m_name; } ///< Returns the name of the category
-	iset key_fields() const; ///< Returns the cif::iset of key field names. Retrieved from the @ref category_validator for this category
-	std::set<uint16_t> key_field_indices() const; ///< Returns a set of indices for the key fields.
+
+	[[deprecated("use key_items instead")]] iset key_fields() const; ///< Returns the cif::iset of key item names. Retrieved from the @ref category_validator for this category
+
+	iset key_items() const; ///< Returns the cif::iset of key item names. Retrieved from the @ref category_validator for this category
+
+	[[deprecated("use key_item_indices instead")]] std::set<uint16_t> key_field_indices() const; ///< Returns a set of indices for the key items.
+
+	std::set<uint16_t> key_item_indices() const; ///< Returns a set of indices for the key items.
 
 	/// @brief Set the validator for this category to @a v
 	/// @param v The category_validator to assign. A nullptr value is allowed.
@@ -162,7 +198,7 @@ class category
 
 	/// @brief Validate links, that means, values in this category should have an
 	/// accompanying value in parent categories.
-	/// 
+	///
 	/// @note
 	/// The code makes one exception when validating missing links and that's between
 	/// *atom_site* and a parent *pdbx_poly_seq_scheme* or *entity_poly_seq*.
@@ -265,7 +301,7 @@ class category
 	/// Return the theoretical maximum number or rows that can be stored
 	size_t max_size() const
 	{
-		return std::numeric_limits<size_t>::max();	// this is a bit optimistic, I guess
+		return std::numeric_limits<size_t>::max(); // this is a bit optimistic, I guess
 	}
 
 	/// Return true if the category is empty
@@ -281,12 +317,12 @@ class category
 	using key_type = row_initializer;
 
 	/// @brief Return a row_handle for the row specified by \a key
-	/// @param key The value for the key, fields specified in the dictionary should have a value
+	/// @param key The value for the key, items specified in the dictionary should have a value
 	/// @return The row found in the index, or an undefined row_handle
 	row_handle operator[](const key_type &key);
 
 	/// @brief Return a const row_handle for the row specified by \a key
-	/// @param key The value for the key, fields specified in the dictionary should have a value
+	/// @param key The value for the key, items specified in the dictionary should have a value
 	/// @return The row found in the index, or an undefined row_handle
 	const row_handle operator[](const key_type &key) const
 	{
@@ -301,15 +337,15 @@ class category
 	/// @code{.cpp}
 	/// for (const auto &[name, value] : cat.rows<std::string,int>("item_name", "item_value"))
 	///   std::cout << name << ": " << value << '\n';
-	/// @endcode 
+	/// @endcode
 	///
-	/// @tparam Ts The types for the columns requested
-	/// @param names The names for the columns requested
+	/// @tparam Ts The types for the items requested
+	/// @param names The names for the items requested
 
 	template <typename... Ts, typename... Ns>
 	iterator_proxy<const category, Ts...> rows(Ns... names) const
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of column titles should be equal to the number of types to return");
+		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of item names should be equal to the number of types to return");
 		return iterator_proxy<const category, Ts...>(*this, begin(), { names... });
 	}
 
@@ -320,19 +356,19 @@ class category
 	/// for (const auto &[name, value] : cat.rows<std::string,int>("item_name", "item_value"))
 	///   std::cout << name << ": " << value << '\n';
 	///
-	/// // or in case we only need one column:
+	/// // or in case we only need one item:
 	///
 	/// for (int id : cat.rows<int>("id"))
 	///   std::cout << id << '\n';
-	/// @endcode 
+	/// @endcode
 	///
-	/// @tparam Ts The types for the columns requested
-	/// @param names The names for the columns requested
+	/// @tparam Ts The types for the items requested
+	/// @param names The names for the items requested
 
 	template <typename... Ts, typename... Ns>
 	iterator_proxy<category, Ts...> rows(Ns... names)
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of column titles should be equal to the number of types to return");
+		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of item names should be equal to the number of types to return");
 		return iterator_proxy<category, Ts...>(*this, begin(), { names... });
 	}
 
@@ -343,7 +379,7 @@ class category
 	/// @code{.cpp}
 	/// for (row_handle rh : cat.find(cif::key("first_name") == "John" and cif::key("last_name") == "Doe"))
 	///    .. // do something with rh
-	/// @endcode 
+	/// @endcode
 	///
 	/// @param cond The condition for the query
 	/// @return A special iterator that loops over all elements that match. The iterator can be dereferenced
@@ -397,17 +433,17 @@ class category
 	/// @code{.cpp}
 	/// for (const auto &[name, value] : cat.find<std::string,int>(cif::key("item_value") > 10, "item_name", "item_value"))
 	///    std::cout << name << ": " << value << '\n';
-	/// @endcode 
+	/// @endcode
 	///
 	/// @param cond The condition for the query
-	/// @tparam Ts The types for the columns requested
-	/// @param names The names for the columns requested
+	/// @tparam Ts The types for the items requested
+	/// @param names The names for the items requested
 	/// @return A special iterator that loops over all elements that match.
 
 	template <typename... Ts, typename... Ns>
 	conditional_iterator_proxy<category, Ts...> find(condition &&cond, Ns... names)
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of column titles should be equal to the number of types to return");
+		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of item names should be equal to the number of types to return");
 		return find<Ts...>(cbegin(), std::move(cond), std::forward<Ns>(names)...);
 	}
 
@@ -415,14 +451,14 @@ class category
 	/// iterator can be used in a structured binding context.
 	///
 	/// @param cond The condition for the query
-	/// @tparam Ts The types for the columns requested
-	/// @param names The names for the columns requested
+	/// @tparam Ts The types for the items requested
+	/// @param names The names for the items requested
 	/// @return A special iterator that loops over all elements that match.
 
 	template <typename... Ts, typename... Ns>
 	conditional_iterator_proxy<const category, Ts...> find(condition &&cond, Ns... names) const
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of column titles should be equal to the number of types to return");
+		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of item names should be equal to the number of types to return");
 		return find<Ts...>(cbegin(), std::move(cond), std::forward<Ns>(names)...);
 	}
 
@@ -431,14 +467,14 @@ class category
 	///
 	/// @param pos Iterator pointing to the location where to start
 	/// @param cond The condition for the query
-	/// @tparam Ts The types for the columns requested
-	/// @param names The names for the columns requested
+	/// @tparam Ts The types for the items requested
+	/// @param names The names for the items requested
 	/// @return A special iterator that loops over all elements that match.
 
 	template <typename... Ts, typename... Ns>
 	conditional_iterator_proxy<category, Ts...> find(const_iterator pos, condition &&cond, Ns... names)
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of column titles should be equal to the number of types to return");
+		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of item names should be equal to the number of types to return");
 		return { *this, pos, std::move(cond), std::forward<Ns>(names)... };
 	}
 
@@ -447,14 +483,14 @@ class category
 	///
 	/// @param pos Iterator pointing to the location where to start
 	/// @param cond The condition for the query
-	/// @tparam Ts The types for the columns requested
-	/// @param names The names for the columns requested
+	/// @tparam Ts The types for the items requested
+	/// @param names The names for the items requested
 	/// @return A special iterator that loops over all elements that match.
 
 	template <typename... Ts, typename... Ns>
 	conditional_iterator_proxy<const category, Ts...> find(const_iterator pos, condition &&cond, Ns... names) const
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of column titles should be equal to the number of types to return");
+		static_assert(sizeof...(Ts) == sizeof...(Ns), "The number of item names should be equal to the number of types to return");
 		return { *this, pos, std::move(cond), std::forward<Ns>(names)... };
 	}
 
@@ -509,30 +545,30 @@ class category
 		return *h.begin();
 	}
 
-	/// @brief Return value for the column named @a column for the single row that
+	/// @brief Return value for the item named @a item for the single row that
 	/// matches @a cond. Throws @a multiple_results_error if there are is not exactly one row
 	/// @tparam The type to use for the result
 	/// @param cond The condition to search for
-	/// @param column The name of the column to return the value for
+	/// @param item The name of the item to return the value for
 	/// @return The value found
 	template <typename T>
-	T find1(condition &&cond, const char *column) const
+	T find1(condition &&cond, std::string_view item) const
 	{
-		return find1<T>(cbegin(), std::move(cond), column);
+		return find1<T>(cbegin(), std::move(cond), item);
 	}
 
-	/// @brief Return value for the column named @a column for the single row that
+	/// @brief Return value for the item named @a item for the single row that
 	/// matches @a cond when starting to search at @a pos.
 	/// Throws @a multiple_results_error if there are is not exactly one row
 	/// @tparam The type to use for the result
 	/// @param pos The location to start the search
 	/// @param cond The condition to search for
-	/// @param column The name of the column to return the value for
+	/// @param item The name of the item to return the value for
 	/// @return The value found
 	template <typename T, std::enable_if_t<not is_optional_v<T>, int> = 0>
-	T find1(const_iterator pos, condition &&cond, const char *column) const
+	T find1(const_iterator pos, condition &&cond, std::string_view item) const
 	{
-		auto h = find<T>(pos, std::move(cond), column);
+		auto h = find<T>(pos, std::move(cond), item);
 
 		if (h.size() != 1)
 			throw multiple_results_error();
@@ -540,18 +576,18 @@ class category
 		return *h.begin();
 	}
 
-	/// @brief Return a value of type std::optional<T> for the column named @a column for the single row that
+	/// @brief Return a value of type std::optional<T> for the item named @a item for the single row that
 	/// matches @a cond when starting to search at @a pos.
 	/// If the row was not found, an empty value is returned.
 	/// @tparam The type to use for the result
 	/// @param pos The location to start the search
 	/// @param cond The condition to search for
-	/// @param column The name of the column to return the value for
+	/// @param item The name of the item to return the value for
 	/// @return The value found, can be empty if no row matches the condition
 	template <typename T, std::enable_if_t<is_optional_v<T>, int> = 0>
-	T find1(const_iterator pos, condition &&cond, const char *column) const
+	T find1(const_iterator pos, condition &&cond, std::string_view item) const
 	{
-		auto h = find<typename T::value_type>(pos, std::move(cond), column);
+		auto h = find<typename T::value_type>(pos, std::move(cond), item);
 
 		if (h.size() > 1)
 			throw multiple_results_error();
@@ -562,34 +598,34 @@ class category
 		return *h.begin();
 	}
 
-	/// @brief Return a std::tuple for the values for the columns named in @a columns
+	/// @brief Return a std::tuple for the values for the items named in @a items
 	/// for the single row that matches @a cond
 	/// Throws @a multiple_results_error if there are is not exactly one row
 	/// @tparam The types to use for the resulting tuple
 	/// @param cond The condition to search for
-	/// @param columns The names of the columns to return the value for
+	/// @param items The names of the items to return the value for
 	/// @return The values found as a single tuple of type std::tuple<Ts...>
 	template <typename... Ts, typename... Cs, typename U = std::enable_if_t<sizeof...(Ts) != 1>>
-	std::tuple<Ts...> find1(condition &&cond, Cs... columns) const
+	std::tuple<Ts...> find1(condition &&cond, Cs... items) const
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Cs), "The number of column titles should be equal to the number of types to return");
-		// static_assert(std::is_same_v<Cs, const char*>..., "The column names should be const char");
-		return find1<Ts...>(cbegin(), std::move(cond), std::forward<Cs>(columns)...);
+		static_assert(sizeof...(Ts) == sizeof...(Cs), "The number of item names should be equal to the number of types to return");
+		// static_assert(std::is_same_v<Cs, const char*>..., "The item names should be const char");
+		return find1<Ts...>(cbegin(), std::move(cond), std::forward<Cs>(items)...);
 	}
 
-	/// @brief Return a std::tuple for the values for the columns named in @a columns
+	/// @brief Return a std::tuple for the values for the items named in @a items
 	/// for the single row that matches @a cond when starting to search at @a pos
 	/// Throws @a multiple_results_error if there are is not exactly one row
 	/// @tparam The types to use for the resulting tuple
 	/// @param pos The location to start the search
 	/// @param cond The condition to search for
-	/// @param columns The names of the columns to return the value for
+	/// @param items The names of the items to return the value for
 	/// @return The values found as a single tuple of type std::tuple<Ts...>
 	template <typename... Ts, typename... Cs, typename U = std::enable_if_t<sizeof...(Ts) != 1>>
-	std::tuple<Ts...> find1(const_iterator pos, condition &&cond, Cs... columns) const
+	std::tuple<Ts...> find1(const_iterator pos, condition &&cond, Cs... items) const
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Cs), "The number of column titles should be equal to the number of types to return");
-		auto h = find<Ts...>(pos, std::move(cond), std::forward<Cs>(columns)...);
+		static_assert(sizeof...(Ts) == sizeof...(Cs), "The number of item names should be equal to the number of types to return");
+		auto h = find<Ts...>(pos, std::move(cond), std::forward<Cs>(items)...);
 
 		if (h.size() != 1)
 			throw multiple_results_error();
@@ -638,74 +674,74 @@ class category
 		return h.empty() ? row_handle{} : *h.begin();
 	}
 
-	/// @brief Return the value for column @a column for the first row that matches condition @a cond
+	/// @brief Return the value for item @a item for the first row that matches condition @a cond
 	/// @tparam The type of the value to return
 	/// @param cond The condition to search for
-	/// @param column The column for which the value should be returned
+	/// @param item The item for which the value should be returned
 	/// @return The value found or a default constructed value if not found
 	template <typename T>
-	T find_first(condition &&cond, const char *column) const
+	T find_first(condition &&cond, std::string_view item) const
 	{
-		return find_first<T>(cbegin(), std::move(cond), column);
+		return find_first<T>(cbegin(), std::move(cond), item);
 	}
 
-	/// @brief Return the value for column @a column for the first row that matches condition @a cond
+	/// @brief Return the value for item @a item for the first row that matches condition @a cond
 	/// when starting the search at @a pos
 	/// @tparam The type of the value to return
 	/// @param pos The location to start searching
 	/// @param cond The condition to search for
-	/// @param column The column for which the value should be returned
+	/// @param item The item for which the value should be returned
 	/// @return The value found or a default constructed value if not found
 	template <typename T>
-	T find_first(const_iterator pos, condition &&cond, const char *column) const
+	T find_first(const_iterator pos, condition &&cond, std::string_view item) const
 	{
-		auto h = find<T>(pos, std::move(cond), column);
+		auto h = find<T>(pos, std::move(cond), item);
 
 		return h.empty() ? T{} : *h.begin();
 	}
 
-	/// @brief Return a tuple containing the values for the columns @a columns for the first row that matches condition @a cond
+	/// @brief Return a tuple containing the values for the items @a items for the first row that matches condition @a cond
 	/// @tparam The types of the values to return
 	/// @param cond The condition to search for
-	/// @param columns The columns for which the values should be returned
+	/// @param items The items for which the values should be returned
 	/// @return The values found or default constructed values if not found
 	template <typename... Ts, typename... Cs, typename U = std::enable_if_t<sizeof...(Ts) != 1>>
-	std::tuple<Ts...> find_first(condition &&cond, Cs... columns) const
+	std::tuple<Ts...> find_first(condition &&cond, Cs... items) const
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Cs), "The number of column titles should be equal to the number of types to return");
-		// static_assert(std::is_same_v<Cs, const char*>..., "The column names should be const char");
-		return find_first<Ts...>(cbegin(), std::move(cond), std::forward<Cs>(columns)...);
+		static_assert(sizeof...(Ts) == sizeof...(Cs), "The number of item names should be equal to the number of types to return");
+		// static_assert(std::is_same_v<Cs, const char*>..., "The item names should be const char");
+		return find_first<Ts...>(cbegin(), std::move(cond), std::forward<Cs>(items)...);
 	}
 
-	/// @brief Return a tuple containing the values for the columns @a columns for the first row that matches condition @a cond
+	/// @brief Return a tuple containing the values for the items @a items for the first row that matches condition @a cond
 	/// when starting the search at @a pos
 	/// @tparam The types of the values to return
 	/// @param pos The location to start searching
 	/// @param cond The condition to search for
-	/// @param columns The columns for which the values should be returned
+	/// @param items The items for which the values should be returned
 	/// @return The values found or default constructed values if not found
 	template <typename... Ts, typename... Cs, typename U = std::enable_if_t<sizeof...(Ts) != 1>>
-	std::tuple<Ts...> find_first(const_iterator pos, condition &&cond, Cs... columns) const
+	std::tuple<Ts...> find_first(const_iterator pos, condition &&cond, Cs... items) const
 	{
-		static_assert(sizeof...(Ts) == sizeof...(Cs), "The number of column titles should be equal to the number of types to return");
-		auto h = find<Ts...>(pos, std::move(cond), std::forward<Cs>(columns)...);
+		static_assert(sizeof...(Ts) == sizeof...(Cs), "The number of item names should be equal to the number of types to return");
+		auto h = find<Ts...>(pos, std::move(cond), std::forward<Cs>(items)...);
 
 		return h.empty() ? std::tuple<Ts...>{} : *h.begin();
 	}
 
 	// --------------------------------------------------------------------
 
-	/// @brief Return the maximum value for column @a column for all rows that match condition @a cond
+	/// @brief Return the maximum value for item @a item for all rows that match condition @a cond
 	/// @tparam The type of the value to return
-	/// @param column The column to use for the value
+	/// @param item The item to use for the value
 	/// @param cond The condition to search for
 	/// @return The value found or the minimal value for the type
 	template <typename T, std::enable_if_t<std::is_arithmetic_v<T>, int> = 0>
-	T find_max(const char *column, condition &&cond) const
+	T find_max(std::string_view item, condition &&cond) const
 	{
 		T result = std::numeric_limits<T>::min();
 
-		for (auto v : find<T>(std::move(cond), column))
+		for (auto v : find<T>(std::move(cond), item))
 		{
 			if (result < v)
 				result = v;
@@ -714,27 +750,27 @@ class category
 		return result;
 	}
 
-	/// @brief Return the maximum value for column @a column for all rows
+	/// @brief Return the maximum value for item @a item for all rows
 	/// @tparam The type of the value to return
-	/// @param column The column to use for the value
+	/// @param item The item to use for the value
 	/// @return The value found or the minimal value for the type
 	template <typename T, std::enable_if_t<std::is_arithmetic_v<T>, int> = 0>
-	T find_max(const char *column) const
+	T find_max(std::string_view item) const
 	{
-		return find_max<T>(column, all());
+		return find_max<T>(item, all());
 	}
 
-	/// @brief Return the minimum value for column @a column for all rows that match condition @a cond
+	/// @brief Return the minimum value for item @a item for all rows that match condition @a cond
 	/// @tparam The type of the value to return
-	/// @param column The column to use for the value
+	/// @param item The item to use for the value
 	/// @param cond The condition to search for
 	/// @return The value found or the maximum value for the type
 	template <typename T, std::enable_if_t<std::is_arithmetic_v<T>, int> = 0>
-	T find_min(const char *column, condition &&cond) const
+	T find_min(std::string_view item, condition &&cond) const
 	{
 		T result = std::numeric_limits<T>::max();
 
-		for (auto v : find<T>(std::move(cond), column))
+		for (auto v : find<T>(std::move(cond), item))
 		{
 			if (result > v)
 				result = v;
@@ -743,20 +779,28 @@ class category
 		return result;
 	}
 
-	/// @brief Return the maximum value for column @a column for all rows
+	/// @brief Return the maximum value for item @a item for all rows
 	/// @tparam The type of the value to return
-	/// @param column The column to use for the value
+	/// @param item The item to use for the value
 	/// @return The value found or the maximum value for the type
 	template <typename T, std::enable_if_t<std::is_arithmetic_v<T>, int> = 0>
-	T find_min(const char *column) const
+	T find_min(std::string_view item) const
 	{
-		return find_min<T>(column, all());
+		return find_min<T>(item, all());
 	}
 
 	/// @brief Return whether a row exists that matches condition @a cond
 	/// @param cond The condition to match
 	/// @return True if a row exists
-	bool exists(condition &&cond) const
+	[[deprecated("Use contains instead")]] bool exists(condition &&cond) const
+	{
+		return contains(std::move(cond));
+	}
+
+	/// @brief Return whether a row exists that matches condition @a cond
+	/// @param cond The condition to match
+	/// @return True if a row exists
+	bool contains(condition &&cond) const
 	{
 		bool result = false;
 
@@ -846,7 +890,7 @@ class category
 	// 	insert_impl(pos, std::move(row));
 	// }
 
-	/// Erase the row pointed to by @a pos and return the iterator to the 
+	/// Erase the row pointed to by @a pos and return the iterator to the
 	/// row following pos.
 	iterator erase(iterator pos);
 
@@ -890,7 +934,7 @@ class category
 			for (auto i = b; i != e; ++i)
 			{
 				// item_value *new_item = this->create_item(*i);
-				r->append(add_column(i->name()), { i->value() });
+				r->append(add_item(i->name()), { i->value() });
 			}
 		}
 		catch (...)
@@ -912,7 +956,6 @@ class category
 	/// result is unique in the context of this category
 	std::string get_unique_id(std::function<std::string(int)> generator = cif::cif_id_for_number);
 
-
 	/// @brief Generate a new, unique ID based on a string prefix followed by a number
 	/// @param prefix The string prefix
 	/// @return a new unique ID
@@ -922,98 +965,195 @@ class category
 			{ return prefix + std::to_string(nr + 1); });
 	}
 
+	/// @brief Generate a new, unique value for a item named @a item_name
+	/// @param item_name The name of the item
+	/// @return a new unique value
+	std::string get_unique_value(std::string_view item_name);
+
 	// --------------------------------------------------------------------
 
-	/// \brief Update a single column named @a tag in the rows that match \a cond to value \a value
+	using value_provider_type = std::function<std::string_view(std::string_view)>;
+
+	/// \brief Update a single item named @a item_name in the rows that match
+	/// \a cond to values provided by a callback function \a value_provider
 	/// making sure the linked categories are updated according to the link.
 	/// That means, child categories are updated if the links are absolute
 	/// and unique. If they are not, the child category rows are split.
 
-	void update_value(condition &&cond, std::string_view tag, std::string_view value)
+	void update_value(condition &&cond, std::string_view item_name,
+		value_provider_type &&value_provider)
 	{
 		auto rs = find(std::move(cond));
 		std::vector<row_handle> rows;
 		std::copy(rs.begin(), rs.end(), std::back_inserter(rows));
-		update_value(rows, tag, value);
+		update_value(rows, item_name, std::move(value_provider));
 	}
 
-	/// \brief Update a single column named @a tag in @a rows to value \a value
+	/// \brief Update a single item named @a item_name in the rows \a rows
+	/// to values provided by a callback function \a value_provider
 	/// making sure the linked categories are updated according to the link.
 	/// That means, child categories are updated if the links are absolute
 	/// and unique. If they are not, the child category rows are split.
 
-	void update_value(const std::vector<row_handle> &rows, std::string_view tag, std::string_view value);
+	void update_value(const std::vector<row_handle> &rows, std::string_view item_name,
+		value_provider_type &&value_provider);
+
+	/// \brief Update a single item named @a item_name in the rows that match \a cond to value \a value
+	/// making sure the linked categories are updated according to the link.
+	/// That means, child categories are updated if the links are absolute
+	/// and unique. If they are not, the child category rows are split.
+
+	void update_value(condition &&cond, std::string_view item_name, std::string_view value)
+	{
+		auto rs = find(std::move(cond));
+		std::vector<row_handle> rows;
+		std::copy(rs.begin(), rs.end(), std::back_inserter(rows));
+		update_value(rows, item_name, value);
+	}
+
+	/// \brief Update a single item named @a item_name in @a rows to value \a value
+	/// making sure the linked categories are updated according to the link.
+	/// That means, child categories are updated if the links are absolute
+	/// and unique. If they are not, the child category rows are split.
+
+	void update_value(const std::vector<row_handle> &rows, std::string_view item_name, std::string_view value)
+	{
+		update_value(rows, item_name, [value](std::string_view)
+			{ return value; });
+	}
 
 	// --------------------------------------------------------------------
+	// Naming used to be very inconsistent. For backward compatibility,
+	// the old function names are here as deprecated variants.
+
 	/// \brief Return the index number for \a column_name
-
-	uint16_t get_column_ix(std::string_view column_name) const
+	[[deprecated("Use get_item_ix instead")]] uint16_t get_column_ix(std::string_view column_name) const
 	{
-		uint16_t result;
-
-		for (result = 0; result < m_columns.size(); ++result)
-		{
-			if (iequals(column_name, m_columns[result].m_name))
-				break;
-		}
-
-		if (VERBOSE > 0 and result == m_columns.size() and m_cat_validator != nullptr) // validate the name, if it is known at all (since it was not found)
-		{
-			auto iv = m_cat_validator->get_validator_for_item(column_name);
-			if (iv == nullptr)
-				std::cerr << "Invalid name used '" << column_name << "' is not a known column in " + m_name << '\n';
-		}
-
-		return result;
+		return get_item_ix(column_name);
 	}
 
 	/// @brief Return the name for column with index @a ix
 	/// @param ix The index number
 	/// @return The name of the column
-	std::string_view get_column_name(uint16_t ix) const
+	[[deprecated("use get_item_name instead")]] std::string_view get_column_name(uint16_t ix) const
 	{
-		if (ix >= m_columns.size())
-			throw std::out_of_range("column index is out of range");
-
-		return m_columns[ix].m_name;
+		return get_item_name(ix);
 	}
 
-	/// @brief Make sure a column with name @a column_name is known and return its index number
-	/// @param column_name The name of the column
-	/// @return The index number of the column
-	uint16_t add_column(std::string_view column_name)
+	/// @brief Make sure a item with name @a item_name is known and return its index number
+	/// @param item_name The name of the item
+	/// @return The index number of the item
+	[[deprecated("use add_item instead")]] uint16_t add_column(std::string_view item_name)
 	{
-		using namespace std::literals;
+		return add_item(item_name);
+	}
 
-		uint16_t result = get_column_ix(column_name);
+	/** @brief Remove column name @a colum_name
+	 * @param column_name The column to be removed
+	 */
+	[[deprecated("use remove_item instead")]] void remove_column(std::string_view column_name)
+	{
+		remove_item(column_name);
+	}
 
-		if (result == m_columns.size())
-		{
-			const item_validator *item_validator = nullptr;
-
-			if (m_cat_validator != nullptr)
-			{
-				item_validator = m_cat_validator->get_validator_for_item(column_name);
-				if (item_validator == nullptr)
-					m_validator->report_error("tag " + std::string(column_name) + " not allowed in category " + m_name, false);
-			}
-
-			m_columns.emplace_back(column_name, item_validator);
-		}
-
-		return result;
+	/** @brief Rename column @a from_name to @a to_name */
+	[[deprecated("use rename_item instead")]] void rename_column(std::string_view from_name, std::string_view to_name)
+	{
+		rename_item(from_name, to_name);
 	}
 
 	/// @brief Return whether a column with name @a name exists in this category
 	/// @param name The name of the column
 	/// @return True if the column exists
-	bool has_column(std::string_view name) const
+	[[deprecated("use has_item instead")]] bool has_column(std::string_view name) const
 	{
-		return get_column_ix(name) < m_columns.size();
+		return has_item(name);
 	}
 
 	/// @brief Return the cif::iset of columns in this category
-	iset get_columns() const;
+	[[deprecated("use get_items instead")]] iset get_columns() const
+	{
+		return get_items();
+	}
+
+	// --------------------------------------------------------------------
+	/// \brief Return the index number for \a item_name
+
+	uint16_t get_item_ix(std::string_view item_name) const
+	{
+		uint16_t result;
+
+		for (result = 0; result < m_items.size(); ++result)
+		{
+			if (iequals(item_name, m_items[result].m_name))
+				break;
+		}
+
+		if (VERBOSE > 0 and result == m_items.size() and m_cat_validator != nullptr) // validate the name, if it is known at all (since it was not found)
+		{
+			auto iv = m_cat_validator->get_validator_for_item(item_name);
+			if (iv == nullptr)
+				std::cerr << "Invalid name used '" << item_name << "' is not a known item in " + m_name << '\n';
+		}
+
+		return result;
+	}
+
+	/// @brief Return the name for item with index @a ix
+	/// @param ix The index number
+	/// @return The name of the item
+	std::string_view get_item_name(uint16_t ix) const
+	{
+		if (ix >= m_items.size())
+			throw std::out_of_range("item index is out of range");
+
+		return m_items[ix].m_name;
+	}
+
+	/// @brief Make sure a item with name @a item_name is known and return its index number
+	/// @param item_name The name of the item
+	/// @return The index number of the item
+	uint16_t add_item(std::string_view item_name)
+	{
+		using namespace std::literals;
+
+		uint16_t result = get_item_ix(item_name);
+
+		if (result == m_items.size())
+		{
+			const item_validator *item_validator = nullptr;
+
+			if (m_cat_validator != nullptr)
+			{
+				item_validator = m_cat_validator->get_validator_for_item(item_name);
+				if (item_validator == nullptr)
+					m_validator->report_error(validation_error::item_not_allowed_in_category, m_name, item_name, false);
+			}
+
+			m_items.emplace_back(item_name, item_validator);
+		}
+
+		return result;
+	}
+
+	/** @brief Remove item name @a colum_name
+	 * @param item_name The item to be removed
+	 */
+	void remove_item(std::string_view item_name);
+
+	/** @brief Rename item @a from_name to @a to_name */
+	void rename_item(std::string_view from_name, std::string_view to_name);
+
+	/// @brief Return whether a item with name @a name exists in this category
+	/// @param name The name of the item
+	/// @return True if the item exists
+	bool has_item(std::string_view name) const
+	{
+		return get_item_ix(name) < m_items.size();
+	}
+
+	/// @brief Return the cif::iset of items in this category
+	iset get_items() const;
 
 	// --------------------------------------------------------------------
 
@@ -1029,30 +1169,36 @@ class category
 
 	// --------------------------------------------------------------------
 
-	/// This function returns effectively the list of fully qualified column
-	/// names, that is category_name + '.' + column_name for each column
-	std::vector<std::string> get_tag_order() const;
+	/// This function returns effectively the list of fully qualified item
+	/// names, that is category_name + '.' + item_name for each item
+	[[deprecated("use get_item_order instead")]] std::vector<std::string> get_tag_order() const
+	{
+		return get_item_order();
+	}
+
+	/// This function returns effectively the list of fully qualified item
+	/// names, that is category_name + '.' + item_name for each item
+	std::vector<std::string> get_item_order() const;
 
 	/// Write the contents of the category to the std::ostream @a os
 	void write(std::ostream &os) const;
 
 	/// @brief Write the contents of the category to the std::ostream @a os and
-	/// use @a order as the order of the columns. If @a addMissingColumns is
-	/// false, columns that do not contain any value will be suppressed
+	/// use @a order as the order of the items. If @a addMissingItems is
+	/// false, items that do not contain any value will be suppressed
 	/// @param os The std::ostream to write to
-	/// @param order The order in which the columns should appear
-	/// @param addMissingColumns When false, empty columns are suppressed from the output
-	void write(std::ostream &os, const std::vector<std::string> &order, bool addMissingColumns = true);
+	/// @param order The order in which the items should appear
+	/// @param addMissingItems When false, empty items are suppressed from the output
+	void write(std::ostream &os, const std::vector<std::string> &order, bool addMissingItems = true);
 
   private:
-	void write(std::ostream &os, const std::vector<uint16_t> &order, bool includeEmptyColumns) const;
+	void write(std::ostream &os, const std::vector<uint16_t> &order, bool includeEmptyItems) const;
 
   public:
-
 	/// friend function to make it possible to do:
 	/// @code {.cpp}
 	/// std::cout << my_category;
-	/// @endcode 
+	/// @endcode
 	friend std::ostream &operator<<(std::ostream &os, const category &cat)
 	{
 		cat.write(os);
@@ -1060,7 +1206,7 @@ class category
 	}
 
   private:
-	void update_value(row *row, uint16_t column, std::string_view value, bool updateLinked, bool validate = true);
+	void update_value(row *row, uint16_t item, std::string_view value, bool updateLinked, bool validate = true);
 
 	void erase_orphans(condition &&cond, category &parent);
 
@@ -1097,12 +1243,12 @@ class category
 
 	row_handle create_copy(row_handle r);
 
-	struct item_column
+	struct item_entry
 	{
 		std::string m_name;
 		const item_validator *m_validator;
 
-		item_column(std::string_view name, const item_validator *validator)
+		item_entry(std::string_view name, const item_validator *validator)
 			: m_name(name)
 			, m_validator(validator)
 		{
@@ -1132,12 +1278,12 @@ class category
 
 	// --------------------------------------------------------------------
 
-	void swap_item(uint16_t column_ix, row_handle &a, row_handle &b);
+	void swap_item(uint16_t item_ix, row_handle &a, row_handle &b);
 
 	// --------------------------------------------------------------------
 
 	std::string m_name;
-	std::vector<item_column> m_columns;
+	std::vector<item_entry> m_items;
 	const validator *m_validator = nullptr;
 	const category_validator *m_cat_validator = nullptr;
 	std::vector<link> m_parent_links, m_child_links;

include/cif++/compound.hpp

@@ -166,6 +166,12 @@ class compound
 		return m_id == "HOH" or m_id == "H2O" or m_id == "WAT";
 	}
 
+	/** \brief Return whether this compound has a type of either 'peptide linking' or 'L-peptide linking' */
+	bool is_peptide() const;
+
+	/** \brief Return whether this compound has a type of either 'DNA linking' or 'RNA linking' */
+	bool is_base() const;
+
 	char one_letter_code() const { return m_one_letter_code; }; ///< Return the one letter code to use in a canonical sequence. If unknown the value '\0' is returned
 	std::string parent_id() const { return m_parent_id; };      ///< Return the parent id code in case a parent is specified (e.g. MET for MSE)
 
@@ -237,25 +243,53 @@ class compound_factory
 	void pop_dictionary();
 
 	/// Return whether @a res_name is a valid and known peptide
+	[[deprecated("use is_peptide or is_std_peptide instead)")]]
 	bool is_known_peptide(const std::string &res_name) const;
 
 	/// Return whether @a res_name is a valid and known base
+	[[deprecated("use is_base or is_std_base instead)")]]
 	bool is_known_base(const std::string &res_name) const;
 
+	/// Return whether @a res_name is a peptide
+	bool is_peptide(std::string_view res_name) const;
+
+	/// Return whether @a res_name is a base
+	bool is_base(std::string_view res_name) const;
+
+	/// Return whether @a res_name is one of the standard peptides
+	bool is_std_peptide(std::string_view res_name) const;
+
+	/// Return whether @a res_name is one of the standard bases
+	bool is_std_base(std::string_view res_name) const;
+
+	/// Return whether @a res_name is a monomer (either base or peptide)
+	bool is_monomer(std::string_view res_name) const;
+
+	/// Return whether @a res_name is one of the standard bases or peptides
+	bool is_std_monomer(std::string_view res_name) const
+	{
+		return is_std_base(res_name) or is_std_peptide(res_name);
+	}
+
+	bool is_water(std::string_view res_name) const
+	{
+		return res_name == "HOH" or res_name == "H2O" or res_name == "WAT";
+	}
+
 	/// \brief Create the compound object for \a id
 	///
 	/// This will create the compound instance for \a id if it doesn't exist already.
 	/// The result is owned by this factory and should not be deleted by the user.
 	/// \param id	The compound ID, a three letter code usually
 	/// \result		The compound, or nullptr if it could not be created (missing info)
-	const compound *create(std::string id);
+	const compound *create(std::string_view id);
 
 	~compound_factory();
 
 	CIFPP_EXPORT static const std::map<std::string, char> kAAMap, ///< Globally accessible static list of the default amino acids
 		kBaseMap;                                                 ///< Globally accessible static list of the default bases
 
-	void report_missing_compound(const std::string &compound_id);
+	void report_missing_compound(std::string_view compound_id);
 
   private:
 	compound_factory();

include/cif++/condition.hpp

@@ -39,17 +39,17 @@
  * query you can use to find rows in a @ref cif::category
  *
  * Conditions are created as standard C++ expressions. That means
- * you can use the standard comparison operators to compare field
+ * you can use the standard comparison operators to compare item
  * contents with a value and boolean operators to chain everything
  * together.
  *
- * To create a query that simply compares one field with one value:
+ * To create a query that simply compares one item with one value:
  *
  * @code {.cpp}
  * cif::condition c = cif::key("id") == 1;
  * @endcode
  * 
- * That will find rows where the ID field contains the number 1. If
+ * That will find rows where the ID item contains the number 1. If
  * using cif::key is a bit too much typing, you can also write:
  * 
  * @code{.cpp}
@@ -64,7 +64,7 @@
  * auto c3 = "id"_key == 1 or "id"_key == 2;
  * @endcode
  * 
- * There are some special values you can use. To find rows with field that
+ * There are some special values you can use. To find rows with item that
  * do not have a value:
  * 
  * @code{.cpp}
@@ -83,7 +83,7 @@
  * auto c6 = cif::all;
  * @endcode
  * 
- * And when you want to search for any column containing the value 'foo':
+ * And when you want to search for any item containing the value 'foo':
  * 
  * @code{.cpp}
  * auto c7 = cif::any == "foo";
@@ -104,31 +104,40 @@ namespace cif
 /// we declare a function to access its contents
 
 /**
- * @brief Get the fields that can be used as key in conditions for a category
+ * @brief Get the items that can be used as key in conditions for a category
  * 
- * @param cat The category whose fields to return
- * @return iset The set of key field names
+ * @param cat The category whose items to return
+ * @return iset The set of key item names
  */
+[[deprecated("use get_category_items instead")]]
 iset get_category_fields(const category &cat);
 
 /**
- * @brief Get the column index for column @a col in category @a cat
+ * @brief Get the items that can be used as key in conditions for a category
  * 
- * @param cat The category
- * @param col The name of the column
- * @return uint16_t The index
+ * @param cat The category whose items to return
+ * @return iset The set of key field names
  */
-uint16_t get_column_ix(const category &cat, std::string_view col);
+iset get_category_items(const category &cat);
 
 /**
- * @brief Return whether the column @a col in category @a cat has a primitive type of *uchar*
+ * @brief Get the item index for item @a col in category @a cat
  * 
  * @param cat The category
- * @param col The column name
+ * @param col The name of the item
+ * @return uint16_t The index
+ */
+uint16_t get_item_ix(const category &cat, std::string_view col);
+
+/**
+ * @brief Return whether the item @a col in category @a cat has a primitive type of *uchar*
+ * 
+ * @param cat The category
+ * @param col The item name
  * @return true If the primitive type is of type *uchar*
  * @return false If the primitive type is not of type *uchar*
  */
-bool is_column_type_uchar(const category &cat, std::string_view col);
+bool is_item_type_uchar(const category &cat, std::string_view col);
 
 // --------------------------------------------------------------------
 // some more templates to be able to do querying
@@ -219,7 +228,7 @@ class condition
 
 	/**
 	 * @brief Prepare the condition to be used on category @a c. This will
-	 * take care of setting the correct indices for fields e.g.
+	 * take care of setting the correct indices for items e.g.
 	 * 
 	 * @param c The category this query should act upon
 	 */
@@ -305,14 +314,14 @@ namespace detail
 {
 	struct key_is_empty_condition_impl : public condition_impl
 	{
-		key_is_empty_condition_impl(const std::string &item_tag)
-			: m_item_tag(item_tag)
+		key_is_empty_condition_impl(const std::string &item_name)
+			: m_item_name(item_name)
 		{
 		}
 
 		condition_impl *prepare(const category &c) override
 		{
-			m_item_ix = get_column_ix(c, m_item_tag);
+			m_item_ix = get_item_ix(c, m_item_name);
 			return this;
 		}
 
@@ -323,23 +332,23 @@ namespace detail
 
 		void str(std::ostream &os) const override
 		{
-			os << m_item_tag << " IS NULL";
+			os << m_item_name << " IS NULL";
 		}
 
-		std::string m_item_tag;
+		std::string m_item_name;
 		uint16_t m_item_ix = 0;
 	};
 
 	struct key_is_not_empty_condition_impl : public condition_impl
 	{
-		key_is_not_empty_condition_impl(const std::string &item_tag)
-			: m_item_tag(item_tag)
+		key_is_not_empty_condition_impl(const std::string &item_name)
+			: m_item_name(item_name)
 		{
 		}
 
 		condition_impl *prepare(const category &c) override
 		{
-			m_item_ix = get_column_ix(c, m_item_tag);
+			m_item_ix = get_item_ix(c, m_item_name);
 			return this;
 		}
 
@@ -350,18 +359,18 @@ namespace detail
 
 		void str(std::ostream &os) const override
 		{
-			os << m_item_tag << " IS NOT NULL";
+			os << m_item_name << " IS NOT NULL";
 		}
 
-		std::string m_item_tag;
+		std::string m_item_name;
 		uint16_t m_item_ix = 0;
 	};
 
 	struct key_equals_condition_impl : public condition_impl
 	{
 		key_equals_condition_impl(item &&i)
-			: m_item_tag(i.name())
-			, m_value(i.value())
+			: m_item_name(i.name())
+			, m_value(std::forward<item>(i).value())
 		{
 		}
 
@@ -374,7 +383,7 @@ namespace detail
 
 		void str(std::ostream &os) const override
 		{
-			os << m_item_tag << (m_icase ? "^ " : " ") << " == " << m_value;
+			os << m_item_name << (m_icase ? "^ " : " ") << " == " << m_value;
 		}
 
 		virtual std::optional<row_handle> single() const override
@@ -390,13 +399,13 @@ namespace detail
 				if (m_single_hit.has_value() or ri->m_single_hit.has_value())
 					return m_single_hit == ri->m_single_hit;
 				else
-					// watch out, both m_item_ix might be the same while tags might be diffent (in case they both do not exist in the category)
-					return m_item_ix == ri->m_item_ix and m_value == ri->m_value and m_item_tag == ri->m_item_tag;
+					// watch out, both m_item_ix might be the same while item_names might be diffent (in case they both do not exist in the category)
+					return m_item_ix == ri->m_item_ix and m_value == ri->m_value and m_item_name == ri->m_item_name;
 			}
 			return this == rhs;
 		}
 
-		std::string m_item_tag;
+		std::string m_item_name;
 		uint16_t m_item_ix = 0;
 		bool m_icase = false;
 		std::string m_value;
@@ -406,7 +415,7 @@ namespace detail
 	struct key_equals_or_empty_condition_impl : public condition_impl
 	{
 		key_equals_or_empty_condition_impl(key_equals_condition_impl *equals)
-			: m_item_tag(equals->m_item_tag)
+			: m_item_name(equals->m_item_name)
 			, m_value(equals->m_value)
 			, m_icase(equals->m_icase)
 			, m_single_hit(equals->m_single_hit)
@@ -415,8 +424,8 @@ namespace detail
 
 		condition_impl *prepare(const category &c) override
 		{
-			m_item_ix = get_column_ix(c, m_item_tag);
-			m_icase = is_column_type_uchar(c, m_item_tag);
+			m_item_ix = get_item_ix(c, m_item_name);
+			m_icase = is_item_type_uchar(c, m_item_name);
 			return this;
 		}
 
@@ -432,7 +441,7 @@ namespace detail
 
 		void str(std::ostream &os) const override
 		{
-			os << '(' << m_item_tag << (m_icase ? "^ " : " ") << " == " << m_value << " OR " << m_item_tag << " IS NULL)";
+			os << '(' << m_item_name << (m_icase ? "^ " : " ") << " == " << m_value << " OR " << m_item_name << " IS NULL)";
 		}
 
 		virtual std::optional<row_handle> single() const override
@@ -448,13 +457,13 @@ namespace detail
 				if (m_single_hit.has_value() or ri->m_single_hit.has_value())
 					return m_single_hit == ri->m_single_hit;
 				else
-					// watch out, both m_item_ix might be the same while tags might be diffent (in case they both do not exist in the category)
-					return m_item_ix == ri->m_item_ix and m_value == ri->m_value and m_item_tag == ri->m_item_tag;
+					// watch out, both m_item_ix might be the same while item_names might be diffent (in case they both do not exist in the category)
+					return m_item_ix == ri->m_item_ix and m_value == ri->m_value and m_item_name == ri->m_item_name;
 			}
 			return this == rhs;
 		}
 
-		std::string m_item_tag;
+		std::string m_item_name;
 		uint16_t m_item_ix = 0;
 		std::string m_value;
 		bool m_icase = false;
@@ -464,8 +473,8 @@ namespace detail
 	struct key_compare_condition_impl : public condition_impl
 	{
 		template <typename COMP>
-		key_compare_condition_impl(const std::string &item_tag, COMP &&comp, const std::string &s)
-			: m_item_tag(item_tag)
+		key_compare_condition_impl(const std::string &item_name, COMP &&comp, const std::string &s)
+			: m_item_name(item_name)
 			, m_compare(std::move(comp))
 			, m_str(s)
 		{
@@ -473,8 +482,8 @@ namespace detail
 
 		condition_impl *prepare(const category &c) override
 		{
-			m_item_ix = get_column_ix(c, m_item_tag);
-			m_icase = is_column_type_uchar(c, m_item_tag);
+			m_item_ix = get_item_ix(c, m_item_name);
+			m_icase = is_item_type_uchar(c, m_item_name);
 			return this;
 		}
 
@@ -485,10 +494,10 @@ namespace detail
 
 		void str(std::ostream &os) const override
 		{
-			os << m_item_tag << (m_icase ? "^ " : " ") << m_str;
+			os << m_item_name << (m_icase ? "^ " : " ") << m_str;
 		}
 
-		std::string m_item_tag;
+		std::string m_item_name;
 		uint16_t m_item_ix = 0;
 		bool m_icase = false;
 		std::function<bool(row_handle, bool)> m_compare;
@@ -497,8 +506,8 @@ namespace detail
 
 	struct key_matches_condition_impl : public condition_impl
 	{
-		key_matches_condition_impl(const std::string &item_tag, const std::regex &rx)
-			: m_item_tag(item_tag)
+		key_matches_condition_impl(const std::string &item_name, const std::regex &rx)
+			: m_item_name(item_name)
 			, m_item_ix(0)
 			, mRx(rx)
 		{
@@ -506,7 +515,7 @@ namespace detail
 
 		condition_impl *prepare(const category &c) override
 		{
-			m_item_ix = get_column_ix(c, m_item_tag);
+			m_item_ix = get_item_ix(c, m_item_name);
 			return this;
 		}
 
@@ -518,10 +527,10 @@ namespace detail
 
 		void str(std::ostream &os) const override
 		{
-			os << m_item_tag << " =~ expression";
+			os << m_item_name << " =~ expression";
 		}
 
-		std::string m_item_tag;
+		std::string m_item_name;
 		uint16_t m_item_ix;
 		std::regex mRx;
 	};
@@ -541,7 +550,7 @@ namespace detail
 			auto &c = r.get_category();
 
 			bool result = false;
-			for (auto &f : get_category_fields(c))
+			for (auto &f : get_category_items(c))
 			{
 				try
 				{
@@ -579,7 +588,7 @@ namespace detail
 			auto &c = r.get_category();
 
 			bool result = false;
-			for (auto &f : get_category_fields(c))
+			for (auto &f : get_category_items(c))
 			{
 				try
 				{
@@ -864,7 +873,7 @@ inline condition operator or(condition &&a, condition &&b)
 			auto ci = static_cast<detail::key_equals_condition_impl *>(a.m_impl);
 			auto ce = static_cast<detail::key_is_empty_condition_impl *>(b.m_impl);
 
-			if (ci->m_item_tag == ce->m_item_tag)
+			if (ci->m_item_name == ce->m_item_name)
 				return condition(new detail::key_equals_or_empty_condition_impl(ci));
 		}
 		else if (typeid(*b.m_impl) == typeid(detail::key_equals_condition_impl) and
@@ -873,7 +882,7 @@ inline condition operator or(condition &&a, condition &&b)
 			auto ci = static_cast<detail::key_equals_condition_impl *>(b.m_impl);
 			auto ce = static_cast<detail::key_is_empty_condition_impl *>(a.m_impl);
 
-			if (ci->m_item_tag == ce->m_item_tag)
+			if (ci->m_item_name == ce->m_item_name)
 				return condition(new detail::key_equals_or_empty_condition_impl(ci));
 		}
 
@@ -887,7 +896,7 @@ inline condition operator or(condition &&a, condition &&b)
 }
 
 /**
- * @brief A helper class to make it possible to search for empty fields (NULL)
+ * @brief A helper class to make it possible to search for empty items (NULL)
  * 
  * @code{.cpp}
  * "id"_key == cif::empty_type();
@@ -909,35 +918,45 @@ struct empty_type
 inline constexpr empty_type null = empty_type();
 
 /**
- * @brief Class to use in creating conditions, creates a reference to a field or column
+ * @brief Class to use in creating conditions, creates a reference to a item or item
  * 
  */
 struct key
 {
 	/**
-	 * @brief Construct a new key object using @a itemTag as name
+	 * @brief Construct a new key object using @a item_name as name
 	 * 
-	 * @param itemTag 
+	 * @param item_name 
 	 */
-	explicit key(const std::string &itemTag)
-		: m_item_tag(itemTag)
+	explicit key(const std::string &item_name)
+		: m_item_name(item_name)
 	{
 	}
 
 	/**
-	 * @brief Construct a new key object using @a itemTag as name
+	 * @brief Construct a new key object using @a item_name as name
 	 * 
-	 * @param itemTag 
+	 * @param item_name 
 	 */
-	explicit key(const char *itemTag)
-		: m_item_tag(itemTag)
+	explicit key(const char *item_name)
+		: m_item_name(item_name)
+	{
+	}
+
+	/**
+	 * @brief Construct a new key object using @a item_name as name
+	 * 
+	 * @param item_name 
+	 */
+	explicit key(std::string_view item_name)
+		: m_item_name(item_name)
 	{
 	}
 
 	key(const key &) = delete;
 	key &operator=(const key &) = delete;
 
-	std::string m_item_tag; ///< The column name
+	std::string m_item_name; ///< The item name
 };
 
 /**
@@ -946,7 +965,7 @@ struct key
 template <typename T>
 condition operator==(const key &key, const T &v)
 {
-	return condition(new detail::key_equals_condition_impl({ key.m_item_tag, v }));
+	return condition(new detail::key_equals_condition_impl({ key.m_item_name, v }));
 }
 
 /**
@@ -955,9 +974,9 @@ condition operator==(const key &key, const T &v)
 inline condition operator==(const key &key, std::string_view value)
 {
 	if (not value.empty())
-		return condition(new detail::key_equals_condition_impl({ key.m_item_tag, value }));
+		return condition(new detail::key_equals_condition_impl({ key.m_item_name, value }));
 	else
-		return condition(new detail::key_is_empty_condition_impl(key.m_item_tag));
+		return condition(new detail::key_is_empty_condition_impl(key.m_item_name));
 }
 
 /**
@@ -987,8 +1006,8 @@ condition operator>(const key &key, const T &v)
 	s << " > " << v;
 
 	return condition(new detail::key_compare_condition_impl(
-		key.m_item_tag, [tag = key.m_item_tag, v](row_handle r, bool icase)
-		{ return r[tag].template compare<T>(v, icase) > 0; },
+		key.m_item_name, [item_name = key.m_item_name, v](row_handle r, bool icase)
+		{ return r[item_name].template compare<T>(v, icase) > 0; },
 		s.str()));
 }
 
@@ -1002,8 +1021,8 @@ condition operator>=(const key &key, const T &v)
 	s << " >= " << v;
 
 	return condition(new detail::key_compare_condition_impl(
-		key.m_item_tag, [tag = key.m_item_tag, v](row_handle r, bool icase)
-		{ return r[tag].template compare<T>(v, icase) >= 0; },
+		key.m_item_name, [item_name = key.m_item_name, v](row_handle r, bool icase)
+		{ return r[item_name].template compare<T>(v, icase) >= 0; },
 		s.str()));
 }
 
@@ -1017,8 +1036,8 @@ condition operator<(const key &key, const T &v)
 	s << " < " << v;
 
 	return condition(new detail::key_compare_condition_impl(
-		key.m_item_tag, [tag = key.m_item_tag, v](row_handle r, bool icase)
-		{ return r[tag].template compare<T>(v, icase) < 0; },
+		key.m_item_name, [item_name = key.m_item_name, v](row_handle r, bool icase)
+		{ return r[item_name].template compare<T>(v, icase) < 0; },
 		s.str()));
 }
 
@@ -1032,8 +1051,8 @@ condition operator<=(const key &key, const T &v)
 	s << " <= " << v;
 
 	return condition(new detail::key_compare_condition_impl(
-		key.m_item_tag, [tag = key.m_item_tag, v](row_handle r, bool icase)
-		{ return r[tag].template compare<T>(v, icase) <= 0; },
+		key.m_item_name, [item_name = key.m_item_name, v](row_handle r, bool icase)
+		{ return r[item_name].template compare<T>(v, icase) <= 0; },
 		s.str()));
 }
 
@@ -1042,7 +1061,7 @@ condition operator<=(const key &key, const T &v)
  */
 inline condition operator==(const key &key, const std::regex &rx)
 {
-	return condition(new detail::key_matches_condition_impl(key.m_item_tag, rx));
+	return condition(new detail::key_matches_condition_impl(key.m_item_name, rx));
 }
 
 /**
@@ -1050,7 +1069,7 @@ inline condition operator==(const key &key, const std::regex &rx)
  */
 inline condition operator==(const key &key, const empty_type &)
 {
-	return condition(new detail::key_is_empty_condition_impl(key.m_item_tag));
+	return condition(new detail::key_is_empty_condition_impl(key.m_item_name));
 }
 
 /**
@@ -1058,20 +1077,20 @@ inline condition operator==(const key &key, const empty_type &)
  */
 inline condition operator!=(const key &key, const empty_type &)
 {
-	return condition(new detail::key_is_not_empty_condition_impl(key.m_item_tag));
+	return condition(new detail::key_is_not_empty_condition_impl(key.m_item_name));
 }
 
 /**
- * @brief Create a condition to search any column for a value @a v if @a v contains a value
+ * @brief Create a condition to search any item for a value @a v if @a v contains a value
  * compare to null if not.
  */
 template <typename T>
 condition operator==(const key &key, const std::optional<T> &v)
 {
 	if (v.has_value())
-		return condition(new detail::key_equals_condition_impl({ key.m_item_tag, *v }));
+		return condition(new detail::key_equals_condition_impl({ key.m_item_name, *v }));
 	else
-		return condition(new detail::key_is_empty_condition_impl(key.m_item_tag));
+		return condition(new detail::key_is_empty_condition_impl(key.m_item_name));
 }
 
 /**
@@ -1089,12 +1108,12 @@ struct any_type
 /** @endcond */
 
 /**
- * @brief A helper for any field constructs
+ * @brief A helper for any item constructs
  */
 inline constexpr any_type any = any_type{};
 
 /**
- * @brief Create a condition to search any column for a value @a v
+ * @brief Create a condition to search any item for a value @a v
  */
 template <typename T>
 condition operator==(const any_type &, const T &v)
@@ -1103,7 +1122,7 @@ condition operator==(const any_type &, const T &v)
 }
 
 /**
- * @brief Create a condition to search any column for a regular expression @a rx
+ * @brief Create a condition to search any item for a regular expression @a rx
  */
 inline condition operator==(const any_type &, const std::regex &rx)
 {
@@ -1121,9 +1140,9 @@ inline condition all()
 namespace literals
 {
 	/**
-	 * @brief Return a cif::key for the column name @a text
+	 * @brief Return a cif::key for the item name @a text
 	 * 
-	 * @param text The name of the column
+	 * @param text The name of the item
 	 * @param length The length of @a text
 	 * @return key The cif::key created
 	 */

include/cif++/datablock.hpp

@@ -61,12 +61,26 @@ class datablock : public std::list<category>
 
 	/** @cond */
 	datablock(const datablock &);
-	datablock(datablock &&) = default;
 
-	datablock &operator=(const datablock &);
-	datablock &operator=(datablock &&) = default;
+	datablock(datablock &&db) noexcept
+	{
+		swap_(*this, db);
+	}
+
+	datablock &operator=(datablock db)
+	{
+		swap_(*this, db);
+		return *this;
+	}
 	/** @endcond */
 
+	friend void swap_(datablock &a, datablock &b) noexcept
+	{
+		std::swap(a.m_name, b.m_name);
+		std::swap(a.m_validator, b.m_validator);
+		std::swap(static_cast<std::list<category>&>(a), static_cast<std::list<category>&>(b));
+	}
+
 	// --------------------------------------------------------------------
 
 	/**
@@ -106,6 +120,15 @@ class datablock : public std::list<category>
 	 */
 	bool is_valid() const;
 
+	/**
+	 * @brief Validates the content of this datablock and all its content
+	 * and updates or removes the audit_conform category to match the result.
+	 * 
+	 * @return true If the content is valid
+	 * @return false If the content is not valid
+	 */
+	bool is_valid();
+
 	/**
 	 * @brief Validates all contained data for valid links between parents and children
 	 * as defined in the validator
@@ -169,7 +192,16 @@ class datablock : public std::list<category>
 	/**
 	 * @brief Get the preferred order of the categories when writing them
 	 */
-	std::vector<std::string> get_tag_order() const;
+	[[deprecated("use get_item_order instead")]]
+	std::vector<std::string> get_tag_order() const
+	{
+		return get_item_order();
+	}
+
+	/**
+	 * @brief Get the preferred order of the categories when writing them
+	 */
+	std::vector<std::string> get_item_order() const;
 
 	/**
 	 * @brief Write out the contents to @a os
@@ -177,9 +209,9 @@ class datablock : public std::list<category>
 	void write(std::ostream &os) const;
 
 	/**
-	 * @brief Write out the contents to @a os using the order defined in @a tag_order
+	 * @brief Write out the contents to @a os using the order defined in @a item_name_order
 	 */
-	void write(std::ostream &os, const std::vector<std::string> &tag_order);
+	void write(std::ostream &os, const std::vector<std::string> &item_name_order);
 
 	/**
 	 * @brief Friend operator<< to write datablock @a db to std::ostream @a os

include/cif++/file.hpp

@@ -100,10 +100,22 @@ class file : public std::list<datablock>
 	}
 
 	/** @cond */
-	file(const file &) = default;
-	file(file &&) = default;
-	file &operator=(const file &) = default;
-	file &operator=(file &&) = default;
+	file(const file &rhs)
+		: std::list<datablock>(rhs)
+	{
+	}
+
+	file(file &&rhs)
+	{
+		this->swap(rhs);
+	}
+
+	file &operator=(file f)
+	{
+		this->swap(f);
+		return *this;
+	}
+
 	/** @endcond */
 
 	/**

include/cif++/item.hpp

@@ -44,7 +44,7 @@
 /** \file item.hpp
  *
  * This file contains the declaration of item but also the item_value and item_handle
- * These handle the storage of and access to the data for a single data field.
+ * These handle the storage of and access to the data for a single data item.
  */
 
 namespace cif
@@ -120,8 +120,6 @@ class item
 		if (r.ec != std::errc())
 			throw std::runtime_error("Could not format number");
 
-		assert(r.ptr >= buffer and r.ptr < buffer + sizeof(buffer));
-		*r.ptr = 0;
 		m_value.assign(buffer, r.ptr - buffer);
 	}
 
@@ -141,8 +139,6 @@ class item
 		if (r.ec != std::errc())
 			throw std::runtime_error("Could not format number");
 
-		assert(r.ptr >= buffer and r.ptr < buffer + sizeof(buffer));
-		*r.ptr = 0;
 		m_value.assign(buffer, r.ptr - buffer);
 	}
 
@@ -158,8 +154,6 @@ class item
 		if (r.ec != std::errc())
 			throw std::runtime_error("Could not format number");
 
-		assert(r.ptr >= buffer and r.ptr < buffer + sizeof(buffer));
-		*r.ptr = 0;
 		m_value.assign(buffer, r.ptr - buffer);
 	}
 
@@ -174,12 +168,21 @@ class item
 
 	/// \brief constructor for an item with name \a name and as
 	/// content value \a value
-	item(const std::string_view name, const std::string_view value)
+	item(const std::string_view name, std::string_view value)
 		: m_name(name)
 		, m_value(value)
 	{
 	}
 
+	/// \brief constructor for an item with name \a name and as
+	/// content value \a value
+	template<typename T, std::enable_if_t<std::is_same_v<T, std::string>, int> = 0>
+	item(const std::string_view name, T &&value)
+		: m_name(name)
+		, m_value(std::move(value))
+	{
+	}
+
 	/// \brief constructor for an item with name \a name and as
 	/// content the optional value \a value
 	template <typename T>
@@ -219,7 +222,8 @@ class item
 	/** @endcond */
 
 	std::string_view name() const { return m_name; }   ///< Return the name of the item
-	std::string_view value() const { return m_value; } ///< Return the value of the item
+	std::string_view value() const & { return m_value; } ///< Return the value of the item
+	std::string value() const && { return std::move(m_value); } ///< Return the value of the item
 
 	/// \brief replace the content of the stored value with \a v
 	void value(std::string_view v) { m_value = v; }
@@ -227,10 +231,10 @@ class item
 	/// \brief empty means either null or unknown
 	bool empty() const { return m_value.empty(); }
 
-	/// \brief returns true if the field contains '.'
+	/// \brief returns true if the item contains '.'
 	bool is_null() const { return m_value == "."; }
 
-	/// \brief returns true if the field contains '?'
+	/// \brief returns true if the item contains '?'
 	bool is_unknown() const { return m_value == "?"; }
 
 	/// \brief the length of the value string
@@ -284,19 +288,16 @@ struct item_value
 	}
 
 	/** @cond */
-	item_value(item_value &&rhs)
+	item_value(item_value &&rhs) noexcept
 		: m_length(std::exchange(rhs.m_length, 0))
 		, m_storage(std::exchange(rhs.m_storage, 0))
 	{
 	}
 
-	item_value &operator=(item_value &&rhs)
+	item_value &operator=(item_value &&rhs) noexcept
 	{
-		if (this != &rhs)
-		{
-			m_length = std::exchange(rhs.m_length, m_length);
-			m_storage = std::exchange(rhs.m_storage, m_storage);
-		}
+		std::swap(m_length, rhs.m_length);
+		std::swap(m_storage, rhs.m_storage);
 		return *this;
 	}
 
@@ -363,8 +364,35 @@ struct item_handle
 	template <typename T>
 	item_handle &operator=(const T &value)
 	{
-		item v{ "", value };
-		assign_value(v);
+		assign_value(item{ "", value }.value());
+		return *this;
+	}
+
+	/**
+	 * @brief Assign value @a value to the item referenced
+	 *
+	 * @tparam T Type of the value
+	 * @param value The value
+	 * @return reference to this item_handle
+	 */
+	template <typename T>
+	item_handle &operator=(T &&value)
+	{
+		assign_value(item{ "", std::move(value) }.value());
+		return *this;
+	}
+
+	/**
+	 * @brief Assign value @a value to the item referenced
+	 *
+	 * @tparam T Type of the value
+	 * @param value The value
+	 * @return reference to this item_handle
+	 */
+	template <size_t N>
+	item_handle &operator=(const char (&value)[N])
+	{
+		assign_value(item{ "", std::move(value) }.value());
 		return *this;
 	}
 
@@ -464,14 +492,14 @@ struct item_handle
 	/** Easy way to test for an empty item */
 	explicit operator bool() const { return not empty(); }
 
-	/// is_null return true if the field contains '.'
+	/// is_null return true if the item contains '.'
 	bool is_null() const
 	{
 		auto txt = text();
 		return txt.length() == 1 and txt.front() == '.';
 	}
 
-	/// is_unknown returns true if the field contains '?'
+	/// is_unknown returns true if the item contains '?'
 	bool is_unknown() const
 	{
 		auto txt = text();
@@ -484,11 +512,11 @@ struct item_handle
 	/**
 	 * @brief Construct a new item handle object
 	 *
-	 * @param column Column index
+	 * @param item Item index
 	 * @param row Reference to the row
 	 */
-	item_handle(uint16_t column, row_handle &row)
-		: m_column(column)
+	item_handle(uint16_t item, row_handle &row)
+		: m_item_ix(item)
 		, m_row_handle(row)
 	{
 	}
@@ -505,10 +533,10 @@ struct item_handle
   private:
 	item_handle();
 
-	uint16_t m_column;
+	uint16_t m_item_ix;
 	row_handle &m_row_handle;
 
-	void assign_value(const item &value);
+	void assign_value(std::string_view value);
 };
 
 // So sad that older gcc implementations of from_chars did not support floats yet...
@@ -556,7 +584,7 @@ struct item_handle::item_value_as<T, std::enable_if_t<std::is_arithmetic_v<T> an
 
 		auto txt = ref.text();
 
-		if (txt.empty())
+		if (ref.empty())
 			result = 1;
 		else
 		{

include/cif++/iterator.hpp

@@ -49,7 +49,7 @@ namespace cif
 /**
  * @brief Implementation of an iterator that can return
  * multiple values in a tuple. Of course, that tuple can
- * then used in structured binding to receive the values
+ * then be used in structured binding to receive the values
  * in a for loop e.g.
  *
  * @tparam Category The category for this iterator
@@ -84,41 +84,38 @@ class iterator_impl
 	iterator_impl() = default;
 
 	iterator_impl(const iterator_impl &rhs) = default;
+	iterator_impl(iterator_impl &&rhs) = default;
 
 	template <typename C2, typename... T2s>
 	iterator_impl(const iterator_impl<C2, T2s...> &rhs)
-		: m_category(rhs.m_category)
-		, m_current(rhs.m_current)
+		: m_current(const_cast<row_handle&>(rhs.m_current))
 		, m_value(rhs.m_value)
-		, m_column_ix(rhs.m_column_ix)
+		, m_item_ix(rhs.m_item_ix)
 	{
 	}
 
 	template <typename IRowType>
 	iterator_impl(iterator_impl<IRowType, Ts...> &rhs)
-		: m_category(rhs.m_category)
-		, m_current(const_cast<row_type *>(rhs.m_current))
+		: m_current(const_cast<row_handle&>(rhs.m_current))
 		, m_value(rhs.m_value)
-		, m_column_ix(rhs.m_column_ix)
+		, m_item_ix(rhs.m_item_ix)
 	{
 		m_value = get(std::make_index_sequence<N>());
 	}
 
 	template <typename IRowType>
 	iterator_impl(const iterator_impl<IRowType> &rhs, const std::array<uint16_t, N> &cix)
-		: m_category(rhs.m_category)
-		, m_current(rhs.m_current)
-		, m_column_ix(cix)
+		: m_current(const_cast<row_handle&>(rhs.m_current))
+		, m_item_ix(cix)
 	{
 		m_value = get(std::make_index_sequence<N>());
 	}
 
-	iterator_impl &operator=(const iterator_impl &i)
+	iterator_impl &operator=(iterator_impl i)
 	{
-		m_category = i.m_category;
-		m_current = i.m_current;
-		m_column_ix = i.m_column_ix;
-		m_value = i.m_value;
+		std::swap(m_current, i.m_current);
+		std::swap(m_item_ix, i.m_item_ix);
+		std::swap(m_value, i.m_value);
 		return *this;
 	}
 
@@ -136,18 +133,18 @@ class iterator_impl
 
 	operator const row_handle() const
 	{
-		return { *m_category, *m_current };
+		return m_current;
 	}
 
 	operator row_handle()
 	{
-		return { *m_category, *m_current };
+		return m_current;
 	}
 
 	iterator_impl &operator++()
 	{
-		if (m_current != nullptr)
-			m_current = m_current->m_next;
+		if (m_current)
+			m_current.m_row = m_current.m_row->m_next;
 
 		m_value = get(std::make_index_sequence<N>());
 
@@ -182,19 +179,12 @@ class iterator_impl
 	template <size_t... Is>
 	tuple_type get(std::index_sequence<Is...>) const
 	{
-		if (m_current != nullptr)
-		{
-			row_handle rh{ *m_category, *m_current };
-			return tuple_type{ rh[m_column_ix[Is]].template as<Ts>()... };
-		}
-
-		return {};
+		return m_current ? tuple_type{ m_current[m_item_ix[Is]].template as<Ts>()... } : tuple_type{};
 	}
 
-	category_type *m_category = nullptr;
-	row_type *m_current = nullptr;
+	row_handle m_current;
 	value_type m_value;
-	std::array<uint16_t, N> m_column_ix;
+	std::array<uint16_t, N> m_item_ix;
 };
 
 /**
@@ -219,37 +209,34 @@ class iterator_impl<Category>
 	using iterator_category = std::forward_iterator_tag;
 	using value_type = row_handle;
 	using difference_type = std::ptrdiff_t;
-	using pointer = row_handle;
-	using reference = row_handle;
+	using pointer = value_type *;
+	using reference = value_type &;
 
 	iterator_impl() = default;
 
 	iterator_impl(const iterator_impl &rhs) = default;
+	iterator_impl(iterator_impl &&rhs) = default;
 
 	template <typename C2>
 	iterator_impl(const iterator_impl<C2> &rhs)
-		: m_category(rhs.m_category)
-		, m_current(const_cast<row_type *>(rhs.m_current))
+		: m_current(const_cast<row_handle &>(rhs.m_current))
 	{
 	}
 
 	iterator_impl(Category &cat, row *current)
-		: m_category(const_cast<category_type *>(&cat))
-		, m_current(current)
+		: m_current(cat, *current)
 	{
 	}
 
 	template <typename IRowType>
 	iterator_impl(const iterator_impl<IRowType> &rhs, const std::array<uint16_t, 0> &)
-		: m_category(rhs.m_category)
-		, m_current(rhs.m_current)
+		: m_current(const_cast<row_handle &>(rhs.m_current))
 	{
 	}
 
-	iterator_impl &operator=(const iterator_impl &i)
+	iterator_impl &operator=(iterator_impl i)
 	{
-		m_category = i.m_category;
-		m_current = i.m_current;
+		std::swap(m_current, i.m_current);
 		return *this;
 	}
 
@@ -257,7 +244,7 @@ class iterator_impl<Category>
 
 	reference operator*()
 	{
-		return { *m_category, *m_current };
+		return m_current;
 	}
 
 	pointer operator->()
@@ -267,18 +254,18 @@ class iterator_impl<Category>
 
 	operator const row_handle() const
 	{
-		return { *m_category, *m_current };
+		return m_current;
 	}
 
 	operator row_handle()
 	{
-		return { *m_category, *m_current };
+		return m_current;
 	}
 
 	iterator_impl &operator++()
 	{
-		if (m_current != nullptr)
-			m_current = m_current->m_next;
+		if (m_current)
+			m_current.m_row = m_current.m_row->m_next;
 
 		return *this;
 	}
@@ -308,8 +295,7 @@ class iterator_impl<Category>
 	/** @endcond */
 
   private:
-	category_type *m_category = nullptr;
-	row_type *m_current = nullptr;
+	row_handle m_current;
 };
 
 /**
@@ -342,41 +328,38 @@ class iterator_impl<Category, T>
 	iterator_impl() = default;
 
 	iterator_impl(const iterator_impl &rhs) = default;
+	iterator_impl(iterator_impl &&rhs) = default;
 
 	template <typename C2, typename T2>
 	iterator_impl(const iterator_impl<C2, T2> &rhs)
-		: m_category(rhs.m_category)
-		, m_current(rhs.m_current)
+		: m_current(rhs.m_current)
 		, m_value(rhs.m_value)
-		, m_column_ix(rhs.m_column_ix)
+		, m_item_ix(rhs.m_item_ix)
 	{
 	}
 
 	template <typename IRowType>
 	iterator_impl(iterator_impl<IRowType, T> &rhs)
-		: m_category(rhs.m_category)
-		, m_current(const_cast<row_type *>(rhs.m_current))
+		: m_current(const_cast<row_handle&>(rhs.m_current))
 		, m_value(rhs.m_value)
-		, m_column_ix(rhs.m_column_ix)
-	{
-		m_value = get(m_current);
-	}
-
-	template <typename IRowType>
-	iterator_impl(const iterator_impl<IRowType> &rhs, const std::array<uint16_t, 1> &cix)
-		: m_category(rhs.m_category)
-		, m_current(rhs.m_current)
-		, m_column_ix(cix[0])
+		, m_item_ix(rhs.m_item_ix)
 	{
 		m_value = get();
 	}
 
-	iterator_impl &operator=(const iterator_impl &i)
+	template <typename IRowType>
+	iterator_impl(const iterator_impl<IRowType> &rhs, const std::array<uint16_t, 1> &cix)
+		: m_current(const_cast<row_handle&>(rhs.m_current))
+		, m_item_ix(cix[0])
 	{
-		m_category = i.m_category;
-		m_current = i.m_current;
-		m_column_ix = i.m_column_ix;
-		m_value = i.m_value;
+		m_value = get();
+	}
+
+	iterator_impl &operator=(iterator_impl i)
+	{
+		std::swap(m_current, i.m_current);
+		std::swap(m_item_ix, i.m_item_ix);
+		std::swap(m_value, i.m_value);
 		return *this;
 	}
 
@@ -394,18 +377,18 @@ class iterator_impl<Category, T>
 
 	operator const row_handle() const
 	{
-		return { *m_category, *m_current };
+		return m_current;
 	}
 
 	operator row_handle()
 	{
-		return { *m_category, *m_current };
+		return m_current;
 	}
 
 	iterator_impl &operator++()
 	{
-		if (m_current != nullptr)
-			m_current = m_current->m_next;
+		if (m_current)
+			m_current.m_row = m_current.m_row->m_next;
 
 		m_value = get();
 
@@ -439,19 +422,12 @@ class iterator_impl<Category, T>
   private:
 	value_type get() const
 	{
-		if (m_current != nullptr)
-		{
-			row_handle rh{ *m_category, *m_current };
-			return rh[m_column_ix].template as<T>();
-		}
-
-		return {};
+		return m_current ?  m_current[m_item_ix].template as<value_type>() : value_type{};
 	}
 
-	category_type *m_category = nullptr;
-	row_type *m_current = nullptr;
+	row_handle m_current;
 	value_type m_value;
-	uint16_t m_column_ix;
+	uint16_t m_item_ix;
 };
 
 // --------------------------------------------------------------------
@@ -482,8 +458,8 @@ class iterator_proxy
 	using iterator = iterator_impl<category_type, Ts...>;
 	using row_iterator = iterator_impl<category_type>;
 
-	iterator_proxy(category_type &cat, row_iterator pos, char const *const columns[N]);
-	iterator_proxy(category_type &cat, row_iterator pos, std::initializer_list<char const *> columns);
+	iterator_proxy(category_type &cat, row_iterator pos, char const *const items[N]);
+	iterator_proxy(category_type &cat, row_iterator pos, std::initializer_list<char const *> items);
 
 	iterator_proxy(iterator_proxy &&p);
 	iterator_proxy &operator=(iterator_proxy &&p);
@@ -492,8 +468,8 @@ class iterator_proxy
 	iterator_proxy &operator=(const iterator_proxy &) = delete;
 	/** @endcond */
 
-	iterator begin() const { return iterator(m_begin, m_column_ix); } ///< Return the iterator pointing to the first row
-	iterator end() const { return iterator(m_end, m_column_ix); }     ///< Return the iterator pointing past the last row
+	iterator begin() const { return iterator(m_begin, m_item_ix); } ///< Return the iterator pointing to the first row
+	iterator end() const { return iterator(m_end, m_item_ix); }     ///< Return the iterator pointing past the last row
 
 	bool empty() const { return m_begin == m_end; }               ///< Return true if the range is empty
 	explicit operator bool() const { return not empty(); }        ///< Easy way to detect if the range is empty
@@ -510,13 +486,13 @@ class iterator_proxy
 		std::swap(m_category, rhs.m_category);
 		std::swap(m_begin, rhs.m_begin);
 		std::swap(m_end, rhs.m_end);
-		std::swap(m_column_ix, rhs.m_column_ix);
+		std::swap(m_item_ix, rhs.m_item_ix);
 	}
 
   private:
 	category_type *m_category;
 	row_iterator m_begin, m_end;
-	std::array<uint16_t, N> m_column_ix;
+	std::array<uint16_t, N> m_item_ix;
 };
 
 // --------------------------------------------------------------------
@@ -562,22 +538,23 @@ class conditional_iterator_proxy
 
 		reference operator*()
 		{
-			return *mBegin;
+			return *m_begin;
 		}
 
 		pointer operator->()
 		{
-			return &*mBegin;
+			m_current = *m_begin;
+			return &m_current;
 		}
 
 		conditional_iterator_impl &operator++()
 		{
-			while (mBegin != mEnd)
+			while (m_begin != m_end)
 			{
-				if (++mBegin == mEnd)
+				if (++m_begin == m_end)
 					break;
 				
-				if (m_condition->operator()(mBegin))
+				if (m_condition->operator()(m_begin))
 					break;
 			}
 
@@ -591,18 +568,22 @@ class conditional_iterator_proxy
 			return result;
 		}
 
-		bool operator==(const conditional_iterator_impl &rhs) const { return mBegin == rhs.mBegin; }
-		bool operator!=(const conditional_iterator_impl &rhs) const { return mBegin != rhs.mBegin; }
+		bool operator==(const conditional_iterator_impl &rhs) const { return m_begin == rhs.m_begin; }
+		bool operator!=(const conditional_iterator_impl &rhs) const { return m_begin != rhs.m_begin; }
+
+		bool operator==(const row_iterator &rhs) const { return m_begin == rhs; }
+		bool operator!=(const row_iterator &rhs) const { return m_begin != rhs; }
 
 		template <typename IRowType, typename... ITs>
-		bool operator==(const iterator_impl<IRowType, ITs...> &rhs) const { return mBegin == rhs; }
+		bool operator==(const iterator_impl<IRowType, ITs...> &rhs) const { return m_begin == rhs; }
 
 		template <typename IRowType, typename... ITs>
-		bool operator!=(const iterator_impl<IRowType, ITs...> &rhs) const { return mBegin != rhs; }
+		bool operator!=(const iterator_impl<IRowType, ITs...> &rhs) const { return m_begin != rhs; }
 
 	  private:
-		CategoryType *mCat;
-		base_iterator mBegin, mEnd;
+		CategoryType *m_cat;
+		base_iterator m_begin, m_end;
+		value_type m_current;
 		const condition *m_condition;
 	};
 
@@ -646,26 +627,26 @@ class conditional_iterator_proxy
 
 /** @cond */
 template <typename Category, typename... Ts>
-iterator_proxy<Category, Ts...>::iterator_proxy(Category &cat, row_iterator pos, char const *const columns[N])
+iterator_proxy<Category, Ts...>::iterator_proxy(Category &cat, row_iterator pos, char const *const items[N])
 	: m_category(&cat)
 	, m_begin(pos)
 	, m_end(cat.end())
 {
 	for (uint16_t i = 0; i < N; ++i)
-		m_column_ix[i] = m_category->get_column_ix(columns[i]);
+		m_item_ix[i] = m_category->get_item_ix(items[i]);
 }
 
 template <typename Category, typename... Ts>
-iterator_proxy<Category, Ts...>::iterator_proxy(Category &cat, row_iterator pos, std::initializer_list<char const *> columns)
+iterator_proxy<Category, Ts...>::iterator_proxy(Category &cat, row_iterator pos, std::initializer_list<char const *> items)
 	: m_category(&cat)
 	, m_begin(pos)
 	, m_end(cat.end())
 {
-	// static_assert(columns.size() == N, "The list of column names should be exactly the same as the list of requested columns");
+	// static_assert(items.size() == N, "The list of item names should be exactly the same as the list of requested items");
 
 	std::uint16_t i = 0;
-	for (auto column : columns)
-		m_column_ix[i++] = m_category->get_column_ix(column);
+	for (auto item : items)
+		m_item_ix[i++] = m_category->get_item_ix(item);
 }
 
 // --------------------------------------------------------------------
@@ -673,13 +654,13 @@ iterator_proxy<Category, Ts...>::iterator_proxy(Category &cat, row_iterator pos,
 template <typename Category, typename... Ts>
 conditional_iterator_proxy<Category, Ts...>::conditional_iterator_impl::conditional_iterator_impl(
 	Category &cat, row_iterator pos, const condition &cond, const std::array<uint16_t, N> &cix)
-	: mCat(&cat)
-	, mBegin(pos, cix)
-	, mEnd(cat.end(), cix)
+	: m_cat(&cat)
+	, m_begin(pos, cix)
+	, m_end(cat.end(), cix)
 	, m_condition(&cond)
 {
 	if (m_condition == nullptr or m_condition->empty())
-		mBegin = mEnd;
+		m_begin = m_end;
 }
 
 template <typename Category, typename... Ts>
@@ -702,7 +683,7 @@ conditional_iterator_proxy<Category, Ts...>::conditional_iterator_proxy(Category
 	, mCBegin(pos)
 	, mCEnd(cat.end())
 {
-	static_assert(sizeof...(Ts) == sizeof...(Ns), "Number of column names should be equal to number of requested value types");
+	static_assert(sizeof...(Ts) == sizeof...(Ns), "Number of item names should be equal to number of requested value types");
 
 	if (m_condition)
 	{
@@ -715,7 +696,7 @@ conditional_iterator_proxy<Category, Ts...>::conditional_iterator_proxy(Category
 		mCBegin = mCEnd;
 
 	uint16_t i = 0;
-	((mCix[i++] = m_cat->get_column_ix(names)), ...);
+	((mCix[i++] = m_cat->get_item_ix(names)), ...);
 }
 
 template <typename Category, typename... Ts>

include/cif++/model.hpp

@@ -72,7 +72,7 @@ class structure;
  *
  * The class atom is a kind of flyweight class. It can be copied
  * with low overhead. All data is stored in the underlying mmCIF
- * categories but some very often used fields are cached in the
+ * categories but some very often used items are cached in the
  * impl.
  *
  * It is also possible to have symmetry copies of atoms. They
@@ -207,7 +207,7 @@ class atom
 	/// \brief Copy assignement operator
 	atom &operator=(const atom &rhs) = default;
 
-	/// \brief Return the field named @a name in the _atom_site category for this atom
+	/// \brief Return the item named @a name in the _atom_site category for this atom
 	std::string get_property(std::string_view name) const
 	{
 		if (not m_impl)
@@ -215,7 +215,7 @@ class atom
 		return m_impl->get_property(name);
 	}
 
-	/// \brief Return the field named @a name in the _atom_site category for this atom cast to an int
+	/// \brief Return the item named @a name in the _atom_site category for this atom cast to an int
 	int get_property_int(std::string_view name) const
 	{
 		if (not m_impl)
@@ -223,7 +223,7 @@ class atom
 		return m_impl->get_property_int(name);
 	}
 
-	/// \brief Return the field named @a name in the _atom_site category for this atom cast to a float
+	/// \brief Return the item named @a name in the _atom_site category for this atom cast to a float
 	float get_property_float(std::string_view name) const
 	{
 		if (not m_impl)
@@ -231,7 +231,7 @@ class atom
 		return m_impl->get_property_float(name);
 	}
 
-	/// \brief Set value for the field named @a name in the _atom_site category to @a value
+	/// \brief Set value for the item named @a name in the _atom_site category to @a value
 	void set_property(const std::string_view name, const std::string &value)
 	{
 		if (not m_impl)
@@ -239,7 +239,7 @@ class atom
 		m_impl->set_property(name, value);
 	}
 
-	/// \brief Set value for the field named @a name in the _atom_site category to @a value
+	/// \brief Set value for the item named @a name in the _atom_site category to @a value
 	template <typename T, std::enable_if_t<std::is_arithmetic_v<T>, int> = 0>
 	void set_property(const std::string_view name, const T &value)
 	{
@@ -730,7 +730,7 @@ class sugar : public residue
 	/**
 	 * @brief Return the sugar number in the glycosylation tree
 	 *
-	 * To store the sugar number, the auth_seq_id field has been overloaded
+	 * To store the sugar number, the auth_seq_id item has been overloaded
 	 * in the specification. But since a sugar number should be, ehm, a number
 	 * and auth_seq_id is specified to contain a string, we do a check here
 	 * to see if it really is a number.

include/cif++/parser.hpp

@@ -143,9 +143,9 @@ class sac_parser
 
 	enum class CIFToken
 	{
-		Unknown,
+		UNKNOWN,
 
-		Eof,
+		END_OF_FILE,
 
 		DATA,
 		LOOP,
@@ -153,24 +153,24 @@ class sac_parser
 		SAVE_,
 		SAVE_NAME,
 		STOP,
-		Tag,
-		Value
+		ITEM_NAME,
+		VALUE
 	};
 
 	static constexpr const char *get_token_name(CIFToken token)
 	{
 		switch (token)
 		{
-			case CIFToken::Unknown: return "Unknown";
-			case CIFToken::Eof: return "Eof";
+			case CIFToken::UNKNOWN: return "Unknown";
+			case CIFToken::END_OF_FILE: return "Eof";
 			case CIFToken::DATA: return "DATA";
 			case CIFToken::LOOP: return "LOOP";
 			case CIFToken::GLOBAL: return "GLOBAL";
 			case CIFToken::SAVE_: return "SAVE";
 			case CIFToken::SAVE_NAME: return "SAVE+name";
 			case CIFToken::STOP: return "STOP";
-			case CIFToken::Tag: return "Tag";
-			case CIFToken::Value: return "Value";
+			case CIFToken::ITEM_NAME: return "Tag";
+			case CIFToken::VALUE: return "Value";
 			default: return "Invalid token parameter";
 		}
 	}
@@ -267,9 +267,9 @@ class sac_parser
 		QuotedString,
 		QuotedStringQuote,
 		UnquotedString,
-		Tag,
-		TextField,
-		TextFieldNL,
+		ItemName,
+		TextItem,
+		TextItemNL,
 		Reserved,
 		Value
 	};

include/cif++/pdb.hpp

@@ -28,6 +28,8 @@
 
 #include "cif++/file.hpp"
 
+#include <system_error>
+
 /**
  * @file pdb.hpp
  *
@@ -107,9 +109,10 @@ inline void write(const std::filesystem::path &p, const file &f)
  *
  * \param file The cif::file that hopefully contains some valid data
  * \param dictionary The mmcif dictionary to use
+ * \result Returns true if the resulting file is valid
  */
 
-void reconstruct_pdbx(file &pdbx_file, std::string_view dictionary = "mmcif_pdbx");
+bool reconstruct_pdbx(file &pdbx_file, std::string_view dictionary = "mmcif_pdbx");
 
 /** \brief This is an extension to cif::validator, use the logic in common
  * PDBx files to see if the file is internally consistent.
@@ -119,6 +122,8 @@ void reconstruct_pdbx(file &pdbx_file, std::string_view dictionary = "mmcif_pdbx
  * atom_site -> pdbx_poly_seq_scheme -> entity_poly_seq -> entity_poly -> entity
  *
  * Use the common \ref cif::VERBOSE flag to turn on diagnostic messages.
+ * 
+ * This function throws a std::system_error in case of an error
  *
  * \param file The input file
  * \param dictionary The mmcif dictionary to use
@@ -127,6 +132,43 @@ void reconstruct_pdbx(file &pdbx_file, std::string_view dictionary = "mmcif_pdbx
 
 bool is_valid_pdbx_file(const file &pdbx_file, std::string_view dictionary = "mmcif_pdbx");
 
+/** \brief This is an extension to cif::validator, use the logic in common
+ * PDBx files to see if the file is internally consistent.
+ *
+ * This function for now checks if the following categories are consistent:
+ *
+ * atom_site -> pdbx_poly_seq_scheme -> entity_poly_seq -> entity_poly -> entity
+ *
+ * Use the common \ref cif::VERBOSE flag to turn on diagnostic messages.
+ * 
+ * The dictionary is assumed to be specified in the file or to be the
+ * default mmcif_pdbx.dic dictionary.
+ *
+ * \param file The input file
+ * \param ec The error_code in case something was wrong
+ * \result Returns true if the file was valid and consistent
+ */
+
+bool is_valid_pdbx_file(const file &pdbx_file, std::error_code &ec);
+
+/** \brief This is an extension to cif::validator, use the logic in common
+ * PDBx files to see if the file is internally consistent.
+ *
+ * This function for now checks if the following categories are consistent:
+ *
+ * atom_site -> pdbx_poly_seq_scheme -> entity_poly_seq -> entity_poly -> entity
+ *
+ * Use the common \ref cif::VERBOSE flag to turn on diagnostic messages.
+ * 
+ * \param file The input file
+ * \param dictionary The dictionary to use
+ * \param ec The error_code in case something was wrong
+ * \result Returns true if the file was valid and consistent
+ */
+
+bool is_valid_pdbx_file(const file &pdbx_file, std::string_view dictionary,
+	std::error_code &ec);
+
 // --------------------------------------------------------------------
 // Other I/O related routines
 

include/cif++/point.hpp

@@ -35,7 +35,10 @@
 
 #if __has_include(<clipper/core/coords.h>)
 #define HAVE_LIBCLIPPER 1
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wignored-qualifiers"
 #include <clipper/core/coords.h>
+#pragma GCC diagnostic pop
 #endif
 
 /** \file point.hpp

include/cif++/row.hpp

@@ -51,7 +51,7 @@
  * std::string name = rh["label_atom_id"].as<std::string>();
  * 
  * // by index:
- * uint16_t ix = atom_site.get_column_ix("label_atom_id");
+ * uint16_t ix = atom_site.get_item_ix("label_atom_id");
  * assert(rh[ix].as<std::string() == name);
  * @endcode
  * 
@@ -87,15 +87,15 @@ namespace detail
 	{
 		static constexpr size_t N = sizeof...(C);
 
-		get_row_result(const row_handle &r, std::array<uint16_t, N> &&columns)
+		get_row_result(const row_handle &r, std::array<uint16_t, N> &&items)
 			: m_row(r)
-			, m_columns(std::move(columns))
+			, m_items(std::move(items))
 		{
 		}
 
 		const item_handle operator[](uint16_t ix) const
 		{
-			return m_row[m_columns[ix]];
+			return m_row[m_items[ix]];
 		}
 
 		template <typename... Ts, std::enable_if_t<N == sizeof...(Ts), int> = 0>
@@ -107,11 +107,11 @@ namespace detail
 		template <typename... Ts, size_t... Is>
 		std::tuple<Ts...> get(std::index_sequence<Is...>) const
 		{
-			return std::tuple<Ts...>{ m_row[m_columns[Is]].template as<Ts>()... };
+			return std::tuple<Ts...>{ m_row[m_items[Is]].template as<Ts>()... };
 		}
 
 		const row_handle &m_row;
-		std::array<uint16_t, N> m_columns;
+		std::array<uint16_t, N> m_items;
 	};
 
 	// we want to be able to tie some variables to a get_row_result, for this we use tiewraps
@@ -208,6 +208,7 @@ class row_handle
 	friend class category;
 	friend class category_index;
 	friend class row_initializer;
+	template <typename, typename...> friend class iterator_impl;
 
 	row_handle() = default;
 
@@ -244,70 +245,70 @@ class row_handle
 		return not empty();
 	}
 
-	/// \brief return a cif::item_handle to the item in column @a column_ix
-	item_handle operator[](uint16_t column_ix)
+	/// \brief return a cif::item_handle to the item in item @a item_ix
+	item_handle operator[](uint16_t item_ix)
 	{
-		return empty() ? item_handle::s_null_item : item_handle(column_ix, *this);
+		return empty() ? item_handle::s_null_item : item_handle(item_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
+	/// \brief return a const cif::item_handle to the item in item @a item_ix
+	const item_handle operator[](uint16_t item_ix) const
 	{
-		return empty() ? item_handle::s_null_item : item_handle(column_ix, const_cast<row_handle &>(*this));
+		return empty() ? item_handle::s_null_item : item_handle(item_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)
+	/// \brief return a cif::item_handle to the item in the item named @a item_name
+	item_handle operator[](std::string_view item_name)
 	{
-		return empty() ? item_handle::s_null_item : item_handle(add_column(column_name), *this);
+		return empty() ? item_handle::s_null_item : item_handle(add_item(item_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
+	/// \brief return a const cif::item_handle to the item in the item named @a item_name
+	const item_handle operator[](std::string_view item_name) const
 	{
-		return empty() ? item_handle::s_null_item : item_handle(get_column_ix(column_name), const_cast<row_handle &>(*this));
+		return empty() ? item_handle::s_null_item : item_handle(get_item_ix(item_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
+	/// to assign the values for the items @a items
 	template <typename... C>
-	auto get(C... columns) const
+	auto get(C... items) const
 	{
-		return detail::get_row_result<C...>(*this, { get_column_ix(columns)... });
+		return detail::get_row_result<C...>(*this, { get_item_ix(items)... });
 	}
 
-	/// \brief Return a tuple of values of types @a Ts for the columns @a columns
+	/// \brief Return a tuple of values of types @a Ts for the items @a items
 	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
+	std::tuple<Ts...> get(C... items) const
 	{
-		return detail::get_row_result<Ts...>(*this, { get_column_ix(columns)... });
+		return detail::get_row_result<Ts...>(*this, { get_item_ix(items)... });
 	}
 
-	/// \brief Get the value of column @a column cast to type @a T
+	/// \brief Get the value of item @a item cast to type @a T
 	template <typename T>
-	T get(const char *column) const
+	T get(const char *item) const
 	{
-		return operator[](get_column_ix(column)).template as<T>();
+		return operator[](get_item_ix(item)).template as<T>();
 	}
 
-	/// \brief Get the value of column @a column cast to type @a T
+	/// \brief Get the value of item @a item cast to type @a T
 	template <typename T>
-	T get(std::string_view column) const
+	T get(std::string_view item) const
 	{
-		return operator[](get_column_ix(column)).template as<T>();
+		return operator[](get_item_ix(item)).template as<T>();
 	}
 
-	/// \brief assign each of the columns named in @a values to their respective value
+	/// \brief assign each of the items 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 
+	/** \brief assign the value @a value to the item named @a name 
 	 * 
 	 * If updateLinked it true, linked records are updated as well.
-	 * That means that if column @a name is part of the link definition
+	 * That means that if item @a 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.
 	 * 
@@ -317,13 +318,13 @@ class row_handle
 
 	void assign(std::string_view name, std::string_view value, bool updateLinked, bool validate = true)
 	{
-		assign(add_column(name), value, updateLinked, validate);
+		assign(add_item(name), value, updateLinked, validate);
 	}
 
-	/** \brief assign the value @a value to column at index @a column
+	/** \brief assign the value @a value to item at index @a item
 	 * 
 	 * If updateLinked it true, linked records are updated as well.
-	 * That means that if column @a column is part of the link definition
+	 * That means that if item @a item 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.
 	 * 
@@ -331,7 +332,7 @@ class row_handle
 	 * 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);
+	void assign(uint16_t item, 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; }
@@ -340,10 +341,10 @@ class row_handle
 	bool operator!=(const row_handle &rhs) const { return m_category != rhs.m_category or m_row != rhs.m_row; }
 
   private:
-	uint16_t get_column_ix(std::string_view name) const;
-	std::string_view get_column_name(uint16_t ix) const;
+	uint16_t get_item_ix(std::string_view name) const;
+	std::string_view get_item_name(uint16_t ix) const;
 
-	uint16_t add_column(std::string_view name);
+	uint16_t add_item(std::string_view name);
 
 	row *get_row()
 	{
@@ -360,7 +361,7 @@ class row_handle
 		assign(i.name(), i.value(), updateLinked);
 	}
 
-	void swap(uint16_t column, row_handle &r);
+	void swap(uint16_t item, row_handle &r);
 
 	category *m_category = nullptr;
 	row *m_row = nullptr;

include/cif++/text.hpp

@@ -317,7 +317,7 @@ inline char tolower(int ch)
 
 // --------------------------------------------------------------------
 
-/** \brief return a tuple consisting of the category and item name for @a tag
+/** \brief return a tuple consisting of the category and item name for @a item_name
  *
  * The category name is stripped of its leading underscore character.
  *
@@ -325,7 +325,19 @@ inline char tolower(int ch)
  * cif 1.0 formatted data.
  */
 
-std::tuple<std::string, std::string> split_tag_name(std::string_view tag);
+[[deprecated("use split_item_name instead")]]
+std::tuple<std::string, std::string> split_tag_name(std::string_view item_name);
+
+
+/** \brief return a tuple consisting of the category and item name for @a item_name
+ *
+ * The category name is stripped of its leading underscore character.
+ *
+ * If no dot character was found, the category name is empty. That's for
+ * cif 1.0 formatted data.
+ */
+
+std::tuple<std::string, std::string> split_item_name(std::string_view item_name);
 
 // --------------------------------------------------------------------
 

include/cif++/utilities.hpp

@@ -113,16 +113,12 @@ namespace colour
 		/**
 		 * @brief Struct for delimited strings.
 		 */
-		template <typename StringType>
 		struct coloured_string_t
 		{
-			static_assert(std::is_reference_v<StringType> or std::is_pointer_v<StringType>,
-				"String type must be pointer or reference");
-
 			/**
 			 * @brief Construct a new coloured string t object
 			 */
-			coloured_string_t(StringType s, colour_type fc, colour_type bc, style_type st)
+			coloured_string_t(std::string_view s, colour_type fc, colour_type bc, style_type st)
 				: m_str(s)
 				, m_fore_colour(static_cast<int>(fc) + 30)
 				, m_back_colour(static_cast<int>(bc) + 40)
@@ -152,12 +148,14 @@ namespace colour
 					   << cs.m_str
 					   << "\033[0m";
 				}
+				else
+					os << cs.m_str;
 
 				return os;
 			}
 
 			/// @cond
-			StringType m_str;
+			std::string_view m_str;
 			int m_fore_colour, m_back_colour;
 			int m_style;
 			/// @endcond
@@ -191,39 +189,13 @@ namespace colour
  * @param st Text style to use
  */
 
-template <typename char_type>
-inline auto coloured(const char_type *str,
+template <typename T>
+	requires std::is_assignable_v<std::string_view, T>
+inline auto coloured(T str,
 	colour::colour_type fg, colour::colour_type bg = colour::colour_type::none,
 	colour::style_type st = colour::style_type::regular)
 {
-	return colour::detail::coloured_string_t<const char_type *>(str, fg, bg, st);
-}
-
-/// @brief Manipulator for coloured strings.
-template <typename char_type, typename traits_type, typename allocator_type>
-inline auto coloured(const std::basic_string<char_type, traits_type, allocator_type> &str,
-	colour::colour_type fg, colour::colour_type bg = colour::colour_type::none,
-	colour::style_type st = colour::style_type::regular)
-{
-	return colour::detail::coloured_string_t<const std::basic_string<char_type, traits_type, allocator_type> &>(str, fg, bg, st);
-}
-
-/// @brief Manipulator for coloured strings.
-template <typename char_type, typename traits_type, typename allocator_type>
-inline auto coloured(std::basic_string<char_type, traits_type, allocator_type> &str,
-	colour::colour_type fg, colour::colour_type bg = colour::colour_type::none,
-	colour::style_type st = colour::style_type::regular)
-{
-	return colour::detail::coloured_string_t<std::basic_string<char_type, traits_type, allocator_type> &>(str, fg, bg, st);
-}
-
-/// @brief Manipulator for coloured strings.
-template <typename char_type, typename traits_type>
-inline auto coloured(std::basic_string_view<char_type, traits_type> &str,
-	colour::colour_type fg, colour::colour_type bg = colour::colour_type::none,
-	colour::style_type st = colour::style_type::regular)
-{
-	return colour::detail::coloured_string_t<std::basic_string_view<char_type, traits_type> &>(str, fg, bg, st);
+	return colour::detail::coloured_string_t(str, fg, bg, st);
 }
 
 // --------------------------------------------------------------------

include/cif++/validate.hpp

@@ -28,9 +28,11 @@
 
 #include "cif++/text.hpp"
 
+#include <cassert>
 #include <filesystem>
 #include <list>
 #include <mutex>
+#include <system_error>
 #include <utility>
 
 /**
@@ -49,27 +51,148 @@ namespace cif
 struct category_validator;
 
 // --------------------------------------------------------------------
+// New: error_code
 
 /**
- * @brief The exception thrown when a validation error occurs
+ * @enum validation_error
+ *
+ * @brief A stronly typed class containing the error codes reported by @ref cif::validator and friends
+ */
+enum class validation_error
+{
+	value_does_not_match_rx = 1,      /**< The value of an item does not conform to the regular expression specified for it */
+	value_is_not_in_enumeration_list, /**< The value of an item is not in the list of values allowed */
+	not_a_known_primitive_type,       /**< The type is not a known primitive type */
+	undefined_category,               /**< Category has no definition in the dictionary */
+	unknown_item,                     /**< The item is not defined to be part of the category */
+	incorrect_item_validator,         /**< Incorrectly specified validator for item */
+	missing_mandatory_items,          /**< Missing mandatory items */
+	missing_key_items,                /**< An index could not be constructed due to missing key items */
+	item_not_allowed_in_category,     /**< Requested item allowed in category according to dictionary */
+	empty_file,                       /**< The file contains no datablocks */
+	empty_datablock,                  /**< The datablock contains no categories */
+	empty_category,                   /**< The category is empty */
+	not_valid_pdbx,                   /**< The file is not a valid PDBx file */
+};
+/**
+ * @brief The implementation for @ref validation_category error messages
  *
  */
-class validation_error : public std::exception
+class validation_category_impl : public std::error_category
 {
   public:
-	/// @brief Constructor
-	validation_error(const std::string &msg);
+	/**
+	 * @brief User friendly name
+	 *
+	 * @return const char*
+	 */
 
-	/// @brief Constructor
-	validation_error(const std::string &cat, const std::string &item,
-		const std::string &msg);
+	const char *name() const noexcept override
+	{
+		return "cif::validation";
+	}
 
-	/// @brief The description of the error
-	const char *what() const noexcept { return m_msg.c_str(); }
+	/**
+	 * @brief Provide the error message as a string for the error code @a ev
+	 *
+	 * @param ev The error code
+	 * @return std::string
+	 */
 
-	/// @cond
-	std::string m_msg;
-	/// @endcond
+	std::string message(int ev) const override
+	{
+		switch (static_cast<validation_error>(ev))
+		{
+			case validation_error::value_does_not_match_rx:
+				return "Value in item does not match regular expression";
+			case validation_error::value_is_not_in_enumeration_list:
+				return "Value is not in the enumerated list of valid values";
+			case validation_error::not_a_known_primitive_type:
+				return "The type is not a known primitive type";
+			case validation_error::undefined_category:
+				return "Category has no definition in the dictionary";
+			case validation_error::unknown_item:
+				return "Item is not defined to be part of the category";
+			case validation_error::incorrect_item_validator:
+				return "Incorrectly specified validator for item";
+			case validation_error::missing_mandatory_items:
+				return "Missing mandatory items";
+			case validation_error::missing_key_items:
+				return "An index could not be constructed due to missing key items";
+			case validation_error::item_not_allowed_in_category:
+				return "Requested item not allowed in category according to dictionary";
+			case validation_error::empty_file:
+				return "The file contains no datablocks";
+			case validation_error::empty_datablock:
+				return "The datablock contains no categories";
+			case validation_error::empty_category:
+				return "The category is empty";
+			case validation_error::not_valid_pdbx:
+				return "The file is not a valid PDBx file";
+
+			default:
+				assert(false);
+				return "unknown error code";
+		}
+	}
+
+	/**
+	 * @brief Return whether two error codes are equivalent, always false in this case
+	 *
+	 */
+
+	bool equivalent(const std::error_code & /*code*/, int /*condition*/) const noexcept override
+	{
+		return false;
+	}
+};
+
+/**
+ * @brief Return the implementation for the validation_category
+ *
+ * @return std::error_category&
+ */
+inline std::error_category &validation_category()
+{
+	static validation_category_impl instance;
+	return instance;
+}
+
+inline std::error_code make_error_code(validation_error e)
+{
+	return std::error_code(static_cast<int>(e), validation_category());
+}
+
+inline std::error_condition make_error_condition(validation_error e)
+{
+	return std::error_condition(static_cast<int>(e), validation_category());
+}
+
+// --------------------------------------------------------------------
+
+class validation_exception : public std::runtime_error
+{
+  public:
+	validation_exception(validation_error err)
+		: validation_exception(make_error_code(err))
+	{
+	}
+
+	validation_exception(validation_error err, std::string_view category)
+		: validation_exception(make_error_code(err), category)
+	{
+	}
+
+	validation_exception(validation_error err, std::string_view category, std::string_view item)
+		: validation_exception(make_error_code(err), category, item)
+	{
+	}
+
+	validation_exception(std::error_code ec);
+
+	validation_exception(std::error_code ec, std::string_view category);
+
+	validation_exception(std::error_code ec, std::string_view category, std::string_view item);
 };
 
 // --------------------------------------------------------------------
@@ -85,6 +208,9 @@ enum class DDL_PrimitiveType
 /// @brief Return the DDL_PrimitiveType encoded in @a s
 DDL_PrimitiveType map_to_primitive_type(std::string_view s);
 
+/// @brief Return the DDL_PrimitiveType encoded in @a s, error reporting variant
+DDL_PrimitiveType map_to_primitive_type(std::string_view s, std::error_code &ec) noexcept;
+
 struct regex_impl;
 
 /**
@@ -146,6 +272,26 @@ struct type_validator
 	int compare(std::string_view a, std::string_view b) const;
 };
 
+/** @brief Item alias, items can be renamed over time
+ */
+
+struct item_alias
+{
+	item_alias(const std::string &alias_name, const std::string &dictionary, const std::string &version)
+		: m_name(alias_name)
+		, m_dict(dictionary)
+		, m_vers(version)
+	{
+	}
+
+	item_alias(const item_alias &) = default;
+	item_alias &operator=(const item_alias &) = default;
+
+	std::string m_name; ///< The alias_name
+	std::string m_dict; ///< The dictionary in which it was known
+	std::string m_vers; ///< The version of the dictionary
+};
+
 /**
  * @brief An item_validator binds a type_validator to an item in
  * a category along with other information found in the dictionary.
@@ -157,28 +303,32 @@ struct type_validator
  */
 struct item_validator
 {
-	std::string m_tag;                        ///< The item name
+	std::string m_item_name;                  ///< The item name
 	bool m_mandatory;                         ///< Flag indicating this item is mandatory
 	const type_validator *m_type;             ///< The type for this item
 	cif::iset m_enums;                        ///< If filled, the set of allowed values
 	std::string m_default;                    ///< If filled, a default value for this item
 	category_validator *m_category = nullptr; ///< The category_validator this item_validator belongs to
+	std::vector<item_alias> m_aliases;        ///< The aliases for this item
 
 	/// @brief Compare based on the name
 	bool operator<(const item_validator &rhs) const
 	{
-		return icompare(m_tag, rhs.m_tag) < 0;
+		return icompare(m_item_name, rhs.m_item_name) < 0;
 	}
 
 	/// @brief Compare based on the name
 	bool operator==(const item_validator &rhs) const
 	{
-		return iequals(m_tag, rhs.m_tag);
+		return iequals(m_item_name, rhs.m_item_name);
 	}
 
 	/// @brief Validate the value in @a value for this item
-	/// Will throw a validation_error exception if it fails
+	/// Will throw a std::system_error exception if it fails
 	void operator()(std::string_view value) const;
+
+	/// @brief A more gentle version of value validation
+	bool validate_value(std::string_view value, std::error_code &ec) const noexcept;
 };
 
 /**
@@ -191,8 +341,8 @@ struct category_validator
 {
 	std::string m_name;                         ///< The name of the category
 	std::vector<std::string> m_keys;            ///< The list of items that make up the key
-	cif::iset m_groups;							///< The category groups this category belongs to
-	cif::iset m_mandatory_fields;               ///< The mandatory fields for this category
+	cif::iset m_groups;                         ///< The category groups this category belongs to
+	cif::iset m_mandatory_items;                ///< The mandatory items for this category
 	std::set<item_validator> m_item_validators; ///< The item validators for the items in this category
 
 	/// @brief return true if this category sorts before @a rhs
@@ -202,10 +352,13 @@ struct category_validator
 	}
 
 	/// @brief Add item_validator @a v to the list of item validators
-	void addItemValidator(item_validator &&v);
+	void add_item_validator(item_validator &&v);
 
-	/// @brief Return the item_validator for item @a tag, may return nullptr
-	const item_validator *get_validator_for_item(std::string_view tag) const;
+	/// @brief Return the item_validator for item @a item_name, may return nullptr
+	const item_validator *get_validator_for_item(std::string_view item_name) const;
+
+	/// @brief Return the item_validator for an item that has as alias name @a item_name, may return nullptr
+	const item_validator *get_validator_for_aliased_item(std::string_view item_name) const;
 };
 
 /**
@@ -284,7 +437,24 @@ class validator
 	std::vector<const link_validator *> get_links_for_child(std::string_view category) const;
 
 	/// @brief Bottleneck function to report an error in validation
-	void report_error(const std::string &msg, bool fatal) const;
+	void report_error(validation_error err, bool fatal = true) const
+	{
+		report_error(make_error_code(err), fatal);
+	}
+
+	/// @brief Bottleneck function to report an error in validation
+	void report_error(std::error_code ec, bool fatal = true) const;
+
+	/// @brief Bottleneck function to report an error in validation
+	void report_error(validation_error err, std::string_view category,
+		std::string_view item, bool fatal = true) const
+	{
+		report_error(make_error_code(err), category, item, fatal);
+	}
+
+	/// @brief Bottleneck function to report an error in validation
+	void report_error(std::error_code ec, std::string_view category,
+		std::string_view item, bool fatal = true) const;
 
 	const std::string &name() const { return m_name; }        ///< Get the name of this validator
 	void set_name(const std::string &name) { m_name = name; } ///< Set the name of this validator

rsrc/ccd-subset.cif

@@ -2712,4 +2712,96 @@ _pdbx_chem_comp_audit.processing_site
 HIS "Create component"  1999-07-08 EBI  
 HIS "Modify descriptor" 2011-06-04 RCSB 
 # 
+data_HOH
+#
 
+_chem_comp.id                                   HOH
+_chem_comp.name                                 WATER
+_chem_comp.type                                 NON-POLYMER
+_chem_comp.pdbx_type                            HETAS
+_chem_comp.formula                              "H2 O"
+_chem_comp.mon_nstd_parent_comp_id              ?
+_chem_comp.pdbx_synonyms                        ?
+_chem_comp.pdbx_formal_charge                   0
+_chem_comp.pdbx_initial_date                    1999-07-08
+_chem_comp.pdbx_modified_date                   2011-06-04
+_chem_comp.pdbx_ambiguous_flag                  N
+_chem_comp.pdbx_release_status                  REL
+_chem_comp.pdbx_replaced_by                     ?
+_chem_comp.pdbx_replaces                        MTO
+_chem_comp.formula_weight                       18.015
+_chem_comp.one_letter_code                      ?
+_chem_comp.three_letter_code                    HOH
+_chem_comp.pdbx_model_coordinates_details       ?
+_chem_comp.pdbx_model_coordinates_missing_flag  N
+_chem_comp.pdbx_ideal_coordinates_details       ?
+_chem_comp.pdbx_ideal_coordinates_missing_flag  N
+_chem_comp.pdbx_model_coordinates_db_code       1NHE
+_chem_comp.pdbx_subcomponent_list               ?
+_chem_comp.pdbx_processing_site                 RCSB
+#   #
+loop_
+_chem_comp_atom.comp_id
+_chem_comp_atom.atom_id
+_chem_comp_atom.alt_atom_id
+_chem_comp_atom.type_symbol
+_chem_comp_atom.charge
+_chem_comp_atom.pdbx_align
+_chem_comp_atom.pdbx_aromatic_flag
+_chem_comp_atom.pdbx_leaving_atom_flag
+_chem_comp_atom.pdbx_stereo_config
+_chem_comp_atom.model_Cartn_x
+_chem_comp_atom.model_Cartn_y
+_chem_comp_atom.model_Cartn_z
+_chem_comp_atom.pdbx_model_Cartn_x_ideal
+_chem_comp_atom.pdbx_model_Cartn_y_ideal
+_chem_comp_atom.pdbx_model_Cartn_z_ideal
+_chem_comp_atom.pdbx_component_atom_id
+_chem_comp_atom.pdbx_component_comp_id
+_chem_comp_atom.pdbx_ordinal
+HOH  O   O   O  0  1  N  N  N  -23.107  18.401  -21.626  -0.064  0.000   0.000  O   HOH  1  
+HOH  H1  1H  H  0  1  N  N  N  -22.157  18.401  -21.626   0.512  0.000  -0.776  H1  HOH  2  
+HOH  H2  2H  H  0  1  N  N  N  -23.424  18.401  -20.730   0.512  0.000   0.776  H2  HOH  3  
+#   #
+loop_
+_chem_comp_bond.comp_id
+_chem_comp_bond.atom_id_1
+_chem_comp_bond.atom_id_2
+_chem_comp_bond.value_order
+_chem_comp_bond.pdbx_aromatic_flag
+_chem_comp_bond.pdbx_stereo_config
+_chem_comp_bond.pdbx_ordinal
+HOH  O  H1  SING  N  N  1  
+HOH  O  H2  SING  N  N  2  
+#   #
+loop_
+_pdbx_chem_comp_descriptor.comp_id
+_pdbx_chem_comp_descriptor.type
+_pdbx_chem_comp_descriptor.program
+_pdbx_chem_comp_descriptor.program_version
+_pdbx_chem_comp_descriptor.descriptor
+HOH  SMILES            ACDLabs               10.04  O                            
+HOH  SMILES_CANONICAL  CACTVS                3.341  O                            
+HOH  SMILES            CACTVS                3.341  O                            
+HOH  SMILES_CANONICAL  "OpenEye OEToolkits"  1.5.0  O                            
+HOH  SMILES            "OpenEye OEToolkits"  1.5.0  O                            
+HOH  InChI             InChI                 1.03   InChI=1S/H2O/h1H2            
+HOH  InChIKey          InChI                 1.03   XLYOFNOQVPJJNP-UHFFFAOYSA-N  
+#   #
+loop_
+_pdbx_chem_comp_identifier.comp_id
+_pdbx_chem_comp_identifier.type
+_pdbx_chem_comp_identifier.program
+_pdbx_chem_comp_identifier.program_version
+_pdbx_chem_comp_identifier.identifier
+HOH  "SYSTEMATIC NAME"  ACDLabs               10.04  water    
+HOH  "SYSTEMATIC NAME"  "OpenEye OEToolkits"  1.5.0  oxidane  
+#   #
+loop_
+_pdbx_chem_comp_audit.comp_id
+_pdbx_chem_comp_audit.action_type
+_pdbx_chem_comp_audit.date
+_pdbx_chem_comp_audit.processing_site
+HOH  "Create component"   1999-07-08  RCSB  
+HOH  "Modify descriptor"  2011-06-04  RCSB  
+##

src/compound.cpp

@@ -310,6 +310,18 @@ float compound::bond_length(const std::string &atomId_1, const std::string &atom
 	return result;
 }
 
+// --------------------------------------------------------------------
+
+bool compound::is_peptide() const
+{
+	return iequals(m_type, "l-peptide linking")	or iequals(m_type, "peptide linking");
+}
+
+bool compound::is_base() const
+{
+	return iequals(m_type, "dna linking")	or iequals(m_type, "rna linking");
+}
+
 // --------------------------------------------------------------------
 // known amino acids and bases
 
@@ -533,12 +545,29 @@ class local_compound_factory_impl : public compound_factory_impl
 		: compound_factory_impl(next)
 		, m_local_file(file)
 	{
+		const std::regex peptideRx("(?:[lmp]-)?peptide", std::regex::icase);
+
+		for (const auto &[id, name, threeLetterCode, group] :
+			file["comp_list"]["chem_comp"].rows<std::string, std::string, std::string, std::string>("id", "name", "three_letter_code", "group"))
+		{
+			auto &rdb = m_local_file["comp_" + id];
+			if (rdb.empty())
+			{
+				std::cerr << "Missing data in restraint file for id " + id + '\n';
+				continue;
+			}
+
+			construct_compound(rdb, id, name, threeLetterCode, group);
+		}
 	}
 
 	compound *create(const std::string &id) override;
 
   private:
-	const cif::file &m_local_file;
+
+	compound *construct_compound(const datablock &db, const std::string &id, const std::string &name, const std::string &three_letter_code, const std::string &group);
+
+	cif::file m_local_file;
 };
 
 compound *local_compound_factory_impl::create(const std::string &id)
@@ -549,12 +578,21 @@ compound *local_compound_factory_impl::create(const std::string &id)
 	{
 		if (db.name() == "comp_" + id)
 		{
-			cif::datablock db_copy(db);
+			auto chem_comp = db.get("chem_comp");
+			if (not chem_comp)
+				break;
 
-			result = new compound(db_copy, 1);
+			try
+			{
+				const auto &[id, name, threeLetterCode, group] =
+					chem_comp->front().get<std::string, std::string, std::string, std::string>("id", "name", "three_letter_code", "group");
 
-			std::shared_lock lock(mMutex);
-			m_compounds.push_back(result);
+				result = construct_compound(db, id, name, threeLetterCode, group);
+			}
+			catch (const std::exception &ex)
+			{
+				std::throw_with_nested(std::runtime_error("Error loading compound " + id));
+			}
 
 			break;
 		}
@@ -563,6 +601,100 @@ compound *local_compound_factory_impl::create(const std::string &id)
 	return result;
 }
 
+compound *local_compound_factory_impl::construct_compound(const datablock &rdb, const std::string &id,
+	const std::string &name, const std::string &three_letter_code, const std::string &group)
+{
+	cif::datablock db(id);
+
+	float formula_weight = 0;
+	int formal_charge = 0;
+	std::map<std::string,size_t> formula_data;
+
+	for (size_t ord = 1; const auto &[atom_id, type_symbol, type, charge, x, y, z] :
+		rdb["chem_comp_atom"].rows<std::string, std::string, std::string, int, float, float, float>(
+			"atom_id", "type_symbol", "type", "charge", "x", "y", "z"))
+	{
+		auto atom = cif::atom_type_traits(type_symbol);
+		formula_weight += atom.weight();
+
+		formula_data[type_symbol] += 1;
+
+		db["chem_comp_atom"].emplace({
+			{ "comp_id", id },
+			{ "atom_id", atom_id },
+			{ "type_symbol", type_symbol },
+			{ "charge", charge },
+			{ "model_Cartn_x",  x, 3 },
+			{ "model_Cartn_y",  y, 3 },
+			{ "model_Cartn_z",  z, 3 },
+			{ "pdbx_ordinal", ord++ }
+		});
+
+		formal_charge += charge;
+	}
+
+	for (size_t ord = 1; const auto &[atom_id_1, atom_id_2, type, aromatic] :
+		rdb["chem_comp_bond"].rows<std::string, std::string, std::string, bool>("atom_id_1", "atom_id_2", "type", "aromatic"))
+	{
+		std::string value_order("SING");
+
+		if (cif::iequals(type, "single") or cif::iequals(type, "sing"))
+			value_order = "SING";
+		else if (cif::iequals(type, "double") or cif::iequals(type, "doub"))
+			value_order = "DOUB";
+		else if (cif::iequals(type, "triple") or cif::iequals(type, "trip"))
+			value_order = "TRIP";
+
+		db["chem_comp_bond"].emplace({
+			{ "comp_id", id },
+			{ "atom_id_1", atom_id_1 },
+			{ "atom_id_2", atom_id_2 },
+			{ "value_order", value_order },
+			{ "pdbx_aromatic_flag", aromatic },
+			// TODO: fetch stereo_config info from chem_comp_chir
+			{ "pdbx_ordinal", ord++ }
+		});
+	}
+
+	db.emplace_back(rdb["pdbx_chem_comp_descriptor"]);
+
+	std::string formula;
+	for (bool first = true; const auto &[symbol, count]: formula_data)
+	{
+		if (std::exchange(first, false))
+			formula += ' ';
+		formula += symbol;
+		if (count > 1)
+			formula += std::to_string(count);
+	}
+
+	std::string type;
+	if (cif::iequals(group, "peptide") or cif::iequals(group, "l-peptide") or cif::iequals(group, "l-peptide linking"))
+		type = "L-PEPTIDE LINKING";
+	else if (cif::iequals(group, "dna"))
+		type = "DNA LINKING";
+	else if (cif::iequals(group, "rna"))
+		type = "RNA LINKING";
+	else
+		type = "NON-POLYMER";
+
+	db["chem_comp"].emplace({
+		{ "id", id },
+		{ "name", name },
+		{ "type", type },
+		{ "formula", formula },
+		{ "pdbx_formal_charge", formal_charge },
+		{ "formula_weight", formula_weight },
+		{ "three_letter_code", three_letter_code }
+	});
+
+	std::shared_lock lock(mMutex);
+
+	auto result = new compound(db);
+	m_compounds.push_back(result);
+	return result;
+}
+
 // --------------------------------------------------------------------
 
 std::unique_ptr<compound_factory> compound_factory::s_instance;
@@ -660,25 +792,67 @@ void compound_factory::pop_dictionary()
 		m_impl = m_impl->next();
 }
 
-const compound *compound_factory::create(std::string id)
+const compound *compound_factory::create(std::string_view id)
 {
-	auto result = m_impl ? m_impl->get(id) : nullptr;
+	auto result = m_impl ? m_impl->get(std::string{ id }) : nullptr;
 	if (not result)
 		report_missing_compound(id);
 	return result;
 }
 
-bool compound_factory::is_known_peptide(const std::string &resName) const
+bool compound_factory::is_known_peptide(const std::string &res_name) const
 {
-	return kAAMap.count(resName) > 0;
+	return kAAMap.count(res_name) > 0;
 }
 
-bool compound_factory::is_known_base(const std::string &resName) const
+bool compound_factory::is_known_base(const std::string &res_name) const
 {
-	return kBaseMap.count(resName) > 0;
+	return kBaseMap.count(res_name) > 0;
 }
 
-void compound_factory::report_missing_compound(const std::string &compound_id)
+/// Return whether @a res_name is a peptide
+bool compound_factory::is_peptide(std::string_view res_name) const
+{
+	bool result = is_std_peptide(res_name);
+	if (not result and m_impl)
+	{
+		auto compound = const_cast<compound_factory&>(*this).create(res_name);
+		result = compound != nullptr and compound->is_peptide();
+	}
+	return result;
+}
+
+/// Return whether @a res_name is a base
+bool compound_factory::is_base(std::string_view res_name) const
+{
+	bool result = is_std_base(res_name);
+	if (not result and m_impl)
+	{
+		auto compound = const_cast<compound_factory&>(*this).create(res_name);
+		result = compound != nullptr and compound->is_base();
+	}
+	return result;
+}
+
+/// Return whether @a res_name is one of the standard peptides
+bool compound_factory::is_std_peptide(std::string_view res_name) const
+{
+	return kAAMap.count(std::string{ res_name }) > 0;
+}
+
+/// Return whether @a res_name is one of the standard bases
+bool compound_factory::is_std_base(std::string_view res_name) const
+{
+	return kBaseMap.count(std::string{ res_name }) > 0;
+}
+
+/// Return whether @a res_name is a monomer (either base or peptide)
+bool compound_factory::is_monomer(std::string_view res_name) const
+{
+	return is_peptide(res_name) or is_base(res_name);
+}
+
+void compound_factory::report_missing_compound(std::string_view compound_id)
 {
 	static bool s_reported = false;
 	if (std::exchange(s_reported, true) == false)
@@ -703,8 +877,8 @@ void compound_factory::report_missing_compound(const std::string &compound_id)
 				  << "update=true\n\n"
 				  << "If you do not have a working cron script, you can manually update the files\n"
 				  << "in /var/cache/libcifpp using the following commands:\n\n"
-				  << "curl -o " << CACHE_DIR << "/components.cif https://files.wwpdb.org/pub/pdb/data/monomers/components.cif.gz\n"
-				  << "curl -o " << CACHE_DIR << "/mmcif_pdbx.dic https://mmcif.wwpdb.org/dictionaries/ascii/mmcif_pdbx_v50.dic.gz\n"
+				  << "curl -o " << CACHE_DIR << "/components.cif https://files.wwpdb.org/pub/pdb/data/monomers/components.cif\n"
+				  << "curl -o " << CACHE_DIR << "/mmcif_pdbx.dic https://mmcif.wwpdb.org/dictionaries/ascii/mmcif_pdbx_v50.dic\n"
 				  << "curl -o " << CACHE_DIR << "/mmcif_ma.dic https://github.com/ihmwg/ModelCIF/raw/master/dist/mmcif_ma.dic\n\n";
 #endif
 

src/condition.cpp

@@ -30,17 +30,17 @@
 namespace cif
 {
 
-iset get_category_fields(const category &cat)
+iset get_category_items(const category &cat)
 {
-	return cat.key_fields();
+	return cat.key_items();
 }
 
-uint16_t get_column_ix(const category &cat, std::string_view col)
+uint16_t get_item_ix(const category &cat, std::string_view col)
 {
-	return cat.get_column_ix(col);
+	return cat.get_item_ix(col);
 }
 
-bool is_column_type_uchar(const category &cat, std::string_view col)
+bool is_item_type_uchar(const category &cat, std::string_view col)
 {
 	bool result = false;
 
@@ -63,14 +63,14 @@ namespace detail
 
 	condition_impl *key_equals_condition_impl::prepare(const category &c)
 	{
-		m_item_ix = c.get_column_ix(m_item_tag);
-		m_icase = is_column_type_uchar(c, m_item_tag);
+		m_item_ix = c.get_item_ix(m_item_name);
+		m_icase = is_item_type_uchar(c, m_item_name);
 
 		if (c.get_cat_validator() != nullptr and
-			c.key_field_indices().contains(m_item_ix) and
-			c.key_field_indices().size() == 1)
+			c.key_item_indices().contains(m_item_ix) and
+			c.key_item_indices().size() == 1)
 		{
-			m_single_hit = c[{ { m_item_tag, m_value } }];
+			m_single_hit = c[{ { m_item_name, m_value } }];
 		}
 
 		return this;

src/datablock.cpp

@@ -38,21 +38,6 @@ datablock::datablock(const datablock &db)
 		cat.update_links(*this);
 }
 
-datablock &datablock::operator=(const datablock &db)
-{
-	if (this != &db)
-	{
-		std::list<category>::operator=(db);
-		m_name = db.m_name;
-		m_validator = db.m_validator;
-
-		for (auto &cat : *this)
-			cat.update_links(*this);
-	}
-
-	return *this;
-}
-
 void datablock::set_validator(const validator *v)
 {
 	m_validator = v;
@@ -85,6 +70,40 @@ bool datablock::is_valid() const
 	return result;
 }
 
+bool datablock::is_valid()
+{
+	if (m_validator == nullptr)
+		throw std::runtime_error("Validator not specified");
+
+	bool result = true;
+	for (auto &cat : *this)
+		result = cat.is_valid() and result;
+	
+	// Add or remove the audit_conform block here.
+	if (result)
+	{
+		// If the dictionary declares an audit_conform category, put it in,
+		// but only if it does not exist already!
+
+		if (m_validator->get_validator_for_category("audit_conform") != nullptr)
+		{
+			auto &audit_conform = operator[]("audit_conform");
+
+			audit_conform.clear();
+			audit_conform.emplace({
+				// clang-format off
+				{ "dict_name", m_validator->name() },
+				{ "dict_version", m_validator->version() }
+				// clang-format on
+			});
+		}
+	}
+	else
+		erase(std::find_if(begin(), end(), [](category &cat) { return cat.name() == "audit_conform"; }), end());
+
+	return result;
+}
+
 bool datablock::validate_links() const
 {
 	bool result = true;
@@ -143,13 +162,6 @@ std::tuple<datablock::iterator, bool> datablock::emplace(std::string_view name)
 		if (iequals(name, i->name()))
 		{
 			is_new = false;
-
-			if (i != begin())
-			{
-				auto n = std::next(i);
-				splice(begin(), *this, i, n);
-			}
-
 			break;
 		}
 
@@ -158,25 +170,24 @@ std::tuple<datablock::iterator, bool> datablock::emplace(std::string_view name)
 
 	if (is_new)
 	{
-		auto &c = emplace_back(name);
-		c.set_validator(m_validator, *this);
+		i = insert(end(), {name});
+		i->set_validator(m_validator, *this);
 	}
 
-	assert(end() != begin());
-	return std::make_tuple(std::prev(end()), is_new);
+	assert(i != end());
+	return std::make_tuple(i, is_new);
 }
 
-std::vector<std::string> datablock::get_tag_order() const
+std::vector<std::string> datablock::get_item_order() const
 {
 	std::vector<std::string> result;
 
 	// for entry and audit_conform on top
-
 	auto ci = find_if(begin(), end(), [](const category &cat)
 		{ return cat.name() == "entry"; });
 	if (ci != end())
 	{
-		auto cto = ci->get_tag_order();
+		auto cto = ci->get_item_order();
 		result.insert(result.end(), cto.begin(), cto.end());
 	}
 
@@ -184,7 +195,7 @@ std::vector<std::string> datablock::get_tag_order() const
 		{ return cat.name() == "audit_conform"; });
 	if (ci != end())
 	{
-		auto cto = ci->get_tag_order();
+		auto cto = ci->get_item_order();
 		result.insert(result.end(), cto.begin(), cto.end());
 	}
 
@@ -192,7 +203,7 @@ std::vector<std::string> datablock::get_tag_order() const
 	{
 		if (cat.name() == "entry" or cat.name() == "audit_conform")
 			continue;
-		auto cto = cat.get_tag_order();
+		auto cto = cat.get_item_order();
 		result.insert(result.end(), cto.begin(), cto.end());
 	}
 
@@ -251,22 +262,16 @@ void datablock::write(std::ostream &os) const
 
 	if (m_validator and size() > 0)
 	{
-		// If the dictionary declares an audit_conform category, put it in,
-		// but only if it does not exist already!
-		if (get("audit_conform") == nullptr and m_validator->get_validator_for_category("audit_conform") != nullptr)
-		{
-			category auditConform("audit_conform");
-			auditConform.emplace({ { "dict_name", m_validator->name() },
-				{ "dict_version", m_validator->version() } });
-			auditConform.write(os);
-		}
-
 		// base order on parent child relationships, parents first
 
 		cat_order_t cat_order;
 
 		for (auto &cat : *this)
+		{
+			if (cat.name() == "entry" or cat.name() == "audit_conform")
+				continue;
 			cat_order.emplace_back(cat.name(), -1, false);
+		}
 
 		for (auto i = cat_order.begin(); i != cat_order.end(); ++i)
 			calculate_cat_order(cat_order, i, *m_validator);
@@ -276,25 +281,18 @@ void datablock::write(std::ostream &os) const
 			const auto &[cat_a, count_a, on_stack_a] = a;
 			const auto &[cat_b, count_b, on_stack_b] = b;
 
-			int d = 0;
-
-			if (cat_a == "audit_conform")
-				d = -1;
-			else if (cat_b == "audit_conform")
-				d = 1;
-			else if (cat_a == "entry")
-				d = -1;
-			else if (cat_b == "entry")
-				d = 1;
-			else
-			{
-				d = std::get<1>(a) - std::get<1>(b);
-				if (d == 0)
-					d = cat_b.compare(cat_a);
-			}
+			int d = std::get<1>(a) - std::get<1>(b);
+			if (d == 0)
+				d = cat_b.compare(cat_a);
 
 			return d < 0; });
 
+		if (auto entry = get("entry"); entry != nullptr)
+			entry->write(os);
+
+		if (auto audit_conform = get("audit_conform"); audit_conform != nullptr)
+			audit_conform->write(os);
+
 		for (auto &&[cat, count, on_stack] : cat_order)
 			get(cat)->write(os);
 	}
@@ -304,20 +302,13 @@ void datablock::write(std::ostream &os) const
 		// and if it exists, _AND_ we have a Validator, write out the
 		// audit_conform record.
 
-		for (auto &cat : *this)
-		{
-			if (cat.name() != "entry")
-				continue;
-
-			cat.write(os);
-
-			break;
-		}
+		if (auto entry = get("entry"); entry != nullptr)
+			entry->write(os);
 
 		// If the dictionary declares an audit_conform category, put it in,
 		// but only if it does not exist already!
-		if (get("audit_conform"))
-			get("audit_conform")->write(os);
+		if (auto audit_conform = get("audit_conform"); audit_conform != nullptr)
+			audit_conform->write(os);
 
 		for (auto &cat : *this)
 		{
@@ -327,16 +318,16 @@ void datablock::write(std::ostream &os) const
 	}
 }
 
-void datablock::write(std::ostream &os, const std::vector<std::string> &tag_order)
+void datablock::write(std::ostream &os, const std::vector<std::string> &item_name_order)
 {
 	os << "data_" << m_name << '\n'
 	   << "# \n";
 
-	std::vector<std::string> cat_order;
-	for (auto &o : tag_order)
+	std::vector<std::string> cat_order{ "entry", "audit_conform" };
+	for (auto &o : item_name_order)
 	{
 		std::string cat_name, item_name;
-		std::tie(cat_name, item_name) = split_tag_name(o);
+		std::tie(cat_name, item_name) = split_item_name(o);
 		if (find_if(cat_order.rbegin(), cat_order.rend(), [cat_name](const std::string &s) -> bool
 				{ return iequals(cat_name, s); }) == cat_order.rend())
 			cat_order.push_back(cat_name);
@@ -349,10 +340,10 @@ void datablock::write(std::ostream &os, const std::vector<std::string> &tag_orde
 			continue;
 
 		std::vector<std::string> items;
-		for (auto &o : tag_order)
+		for (auto &o : item_name_order)
 		{
 			std::string cat_name, item_name;
-			std::tie(cat_name, item_name) = split_tag_name(o);
+			std::tie(cat_name, item_name) = split_item_name(o);
 
 			if (cat_name == c)
 				items.push_back(item_name);
@@ -374,6 +365,10 @@ void datablock::write(std::ostream &os, const std::vector<std::string> &tag_orde
 
 bool datablock::operator==(const datablock &rhs) const
 {
+	// shortcut
+	if (this == &rhs)
+		return true;
+
 	auto &dbA = *this;
 	auto &dbB = rhs;
 

src/dictionary_parser.cpp

@@ -50,7 +50,7 @@ class dictionary_parser : public parser
 
 		try
 		{
-			while (m_lookahead != CIFToken::Eof)
+			while (m_lookahead != CIFToken::END_OF_FILE)
 			{
 				switch (m_lookahead)
 				{
@@ -87,7 +87,7 @@ class dictionary_parser : public parser
 				error("Undefined category '" + iv.first);
 
 			for (auto &v : iv.second)
-				const_cast<category_validator *>(cv)->addItemValidator(std::move(v));
+				const_cast<category_validator *>(cv)->add_item_validator(std::move(v));
 		}
 
 		// check all item validators for having a typeValidator
@@ -128,7 +128,7 @@ class dictionary_parser : public parser
 		datablock::iterator cat = dict.end();
 
 		match(CIFToken::SAVE_NAME);
-		while (m_lookahead == CIFToken::LOOP or m_lookahead == CIFToken::Tag)
+		while (m_lookahead == CIFToken::LOOP or m_lookahead == CIFToken::ITEM_NAME)
 		{
 			if (m_lookahead == CIFToken::LOOP)
 			{
@@ -136,30 +136,30 @@ class dictionary_parser : public parser
 
 				match(CIFToken::LOOP);
 
-				std::vector<std::string> tags;
-				while (m_lookahead == CIFToken::Tag)
+				std::vector<std::string> item_names;
+				while (m_lookahead == CIFToken::ITEM_NAME)
 				{
 					std::string catName, item_name;
-					std::tie(catName, item_name) = split_tag_name(m_token_value);
+					std::tie(catName, item_name) = split_item_name(m_token_value);
 
 					if (cat == dict.end())
 						std::tie(cat, std::ignore) = dict.emplace(catName);
 					else if (not iequals(cat->name(), catName))
 						error("inconsistent categories in loop_");
 
-					tags.push_back(item_name);
-					match(CIFToken::Tag);
+					item_names.push_back(item_name);
+					match(CIFToken::ITEM_NAME);
 				}
 
-				while (m_lookahead == CIFToken::Value)
+				while (m_lookahead == CIFToken::VALUE)
 				{
 					cat->emplace({});
 					auto row = cat->back();
 
-					for (auto tag : tags)
+					for (auto item_name : item_names)
 					{
-						row[tag] = m_token_value;
-						match(CIFToken::Value);
+						row[item_name] = m_token_value;
+						match(CIFToken::VALUE);
 					}
 				}
 
@@ -168,18 +168,18 @@ class dictionary_parser : public parser
 			else
 			{
 				std::string catName, item_name;
-				std::tie(catName, item_name) = split_tag_name(m_token_value);
+				std::tie(catName, item_name) = split_item_name(m_token_value);
 
 				if (cat == dict.end() or not iequals(cat->name(), catName))
 					std::tie(cat, std::ignore) = dict.emplace(catName);
 
-				match(CIFToken::Tag);
+				match(CIFToken::ITEM_NAME);
 
 				if (cat->empty())
 					cat->emplace({});
 				cat->back()[item_name] = m_token_value;
 
-				match(CIFToken::Value);
+				match(CIFToken::VALUE);
 			}
 		}
 
@@ -191,7 +191,7 @@ class dictionary_parser : public parser
 
 			std::vector<std::string> keys;
 			for (auto k : dict["category_key"])
-				keys.push_back(std::get<1>(split_tag_name(k["name"].as<std::string>())));
+				keys.push_back(std::get<1>(split_item_name(k["name"].as<std::string>())));
 
 			iset groups;
 			for (auto g : dict["category_group"])
@@ -224,20 +224,27 @@ class dictionary_parser : public parser
 			// 	}
 			// }
 
+			std::vector<item_alias> aliases;
+			for (const auto &[alias_name, dictionary, version] :
+				dict["item_aliases"].rows<std::string,std::string,std::string>("alias_name", "dictionary", "version"))
+			{
+				aliases.emplace_back(alias_name, dictionary, version);
+			}
+
 			// collect the dict from our dataBlock and construct validators
 			for (auto i : dict["item"])
 			{
-				std::string tagName, category, mandatory;
-				cif::tie(tagName, category, mandatory) = i.get("name", "category_id", "mandatory_code");
+				std::string item, category, mandatory;
+				cif::tie(item, category, mandatory) = i.get("name", "category_id", "mandatory_code");
 
 				std::string cat_name, item_name;
-				std::tie(cat_name, item_name) = split_tag_name(tagName);
+				std::tie(cat_name, item_name) = split_item_name(item);
 
 				if (cat_name.empty() or item_name.empty())
-					error("Invalid tag name in _item.name " + tagName);
+					error("Invalid item name in _item.name " + item);
 
 				if (not iequals(category, cat_name) and not(category.empty() or category == "?"))
-					error("specified category id does match the implicit category name for tag '" + tagName + '\'');
+					error("specified category id does match the implicit category name for item '" + item + '\'');
 				else
 					category = cat_name;
 
@@ -245,7 +252,7 @@ class dictionary_parser : public parser
 
 				auto vi = find(ivs.begin(), ivs.end(), item_validator{ item_name });
 				if (vi == ivs.end())
-					ivs.push_back(item_validator{ item_name, iequals(mandatory, "yes"), tv, ess, defaultValue /*, defaultIsNull*/ });
+					ivs.push_back(item_validator{ item_name, iequals(mandatory, "yes"), tv, ess, defaultValue, nullptr, std::move(aliases) });
 				else
 				{
 					// need to update the itemValidator?
@@ -253,22 +260,22 @@ class dictionary_parser : public parser
 					{
 						if (VERBOSE > 2)
 						{
-							std::cerr << "inconsistent mandatory value for " << tagName << " in dictionary\n";
+							std::cerr << "inconsistent mandatory value for " << item << " in dictionary\n";
 
-							if (iequals(tagName, saveFrameName))
+							if (iequals(item, saveFrameName))
 								std::cerr << "choosing " << mandatory << '\n';
 							else
 								std::cerr << "choosing " << (vi->m_mandatory ? "Y" : "N") << '\n';
 						}
 
-						if (iequals(tagName, saveFrameName))
+						if (iequals(item, saveFrameName))
 							vi->m_mandatory = (iequals(mandatory, "yes"));
 					}
 
 					if (vi->m_type != nullptr and tv != nullptr and vi->m_type != tv)
 					{
 						if (VERBOSE > 1)
-							std::cerr << "inconsistent type for " << tagName << " in dictionary\n";
+							std::cerr << "inconsistent type for " << item << " in dictionary\n";
 					}
 
 					//				vi->mMandatory = (iequals(mandatory, "yes"));
@@ -351,7 +358,7 @@ class dictionary_parser : public parser
 			}
 
 			size_t ix = linkIndex.at(key);
-			addLink(ix, piv->m_tag, civ->m_tag);
+			addLink(ix, piv->m_item_name, civ->m_item_name);
 		}
 
 		// Only process inline linked items if the linked group list is absent
@@ -379,7 +386,7 @@ class dictionary_parser : public parser
 				}
 
 				size_t ix = linkIndex.at(key);
-				addLink(ix, piv->m_tag, civ->m_tag);
+				addLink(ix, piv->m_item_name, civ->m_item_name);
 			}
 		}
 
@@ -410,7 +417,7 @@ class dictionary_parser : public parser
 			for (auto &iv : cv.m_item_validators)
 			{
 				if (iv.m_type == nullptr and cif::VERBOSE >= 0)
-					std::cerr << "Missing item_type for " << iv.m_tag << '\n';
+					std::cerr << "Missing item_type for " << iv.m_item_name << '\n';
 			}
 		}
 	}

src/file.cpp

@@ -158,13 +158,6 @@ std::tuple<file::iterator, bool> file::emplace(std::string_view name)
 		if (iequals(name, i->name()))
 		{
 			is_new = false;
-
-			if (i != begin())
-			{
-				auto n = std::next(i);
-				splice(begin(), *this, i, n);
-			}
-
 			break;
 		}
 
@@ -173,12 +166,12 @@ std::tuple<file::iterator, bool> file::emplace(std::string_view name)
 
 	if (is_new)
 	{
-		auto &db = emplace_back(name);
-		db.set_validator(m_validator);
+		i = insert(end(), { name });
+		i->set_validator(m_validator);
 	}
 
-	assert(begin() != end());
-	return std::make_tuple(std::prev(end()), is_new);
+	assert(i != end());
+	return std::make_tuple(i, is_new);
 }
 
 void file::load(const std::filesystem::path &p)

src/item.cpp

@@ -35,7 +35,7 @@ const item_handle item_handle::s_null_item;
 row_handle s_null_row_handle;
 
 item_handle::item_handle()
-	: m_column(std::numeric_limits<uint16_t>::max())
+	: m_item_ix(std::numeric_limits<uint16_t>::max())
 	, m_row_handle(s_null_row_handle)
 {
 }
@@ -44,7 +44,7 @@ std::string_view item_handle::text() const
 {
 	if (not m_row_handle.empty())
 	{
-		auto iv = m_row_handle.m_row->get(m_column);
+		auto iv = m_row_handle.m_row->get(m_item_ix);
 		if (iv != nullptr)
 			return iv->text();
 	}
@@ -52,17 +52,17 @@ std::string_view item_handle::text() const
 	return {};
 }
 
-void item_handle::assign_value(const item &v)
+void item_handle::assign_value(std::string_view value)
 {
 	assert(not m_row_handle.empty());
-	m_row_handle.assign(m_column, v.value(), true);
+	m_row_handle.assign(m_item_ix, value, true);
 }
 
 void item_handle::swap(item_handle &b)
 {
-	assert(m_column == b.m_column);
+	assert(m_item_ix == b.m_item_ix);
 	// assert(&m_row_handle.m_category == &b.m_row_handle.m_category);
-	m_row_handle.swap(m_column, b.m_row_handle);
+	m_row_handle.swap(m_item_ix, b.m_row_handle);
 }
 
 }

src/model.cpp

@@ -163,9 +163,9 @@ int atom::atom_impl::get_charge() const
 
 // const std::string atom::atom_impl::get_property(const std::string_view name) const
 // {
-// 	for (auto &&[tag, ref] : mCachedRefs)
+// 	for (auto &&[item_name, ref] : mCachedRefs)
 // 	{
-// 		if (tag == name)
+// 		if (item_name == name)
 // 			return ref.as<std::string>();
 // 	}
 
@@ -175,9 +175,9 @@ int atom::atom_impl::get_charge() const
 
 // void atom::atom_impl::set_property(const std::string_view name, const std::string &value)
 // {
-// 	for (auto &&[tag, ref] : mCachedRefs)
+// 	for (auto &&[item_name, ref] : mCachedRefs)
 // 	{
-// 		if (tag != name)
+// 		if (item_name != name)
 // 			continue;
 
 // 		ref = value;
@@ -1783,7 +1783,7 @@ atom &structure::emplace_atom(atom &&atom)
 	std::string symbol = atom.get_property("type_symbol");
 
 	using namespace cif::literals;
-	if (not atom_type.exists("symbol"_key == symbol))
+	if (not atom_type.contains("symbol"_key == symbol))
 		atom_type.emplace({ { "symbol", symbol } });
 
 	return m_atoms.emplace_back(std::move(atom));
@@ -1969,7 +1969,7 @@ void structure::change_residue(residue &res, const std::string &newCompound,
 
 		// create rest
 		auto &chemComp = m_db["chem_comp"];
-		if (not chemComp.exists(key("id") == newCompound))
+		if (not chemComp.contains(key("id") == newCompound))
 		{
 			chemComp.emplace({{"id", newCompound},
 				{"name", compound->name()},
@@ -2702,7 +2702,7 @@ void structure::cleanup_empty_categories()
 	for (auto chemComp : chem_comp)
 	{
 		std::string compID = chemComp["id"].as<std::string>();
-		if (atomSite.exists("label_comp_id"_key == compID or "auth_comp_id"_key == compID))
+		if (atomSite.contains("label_comp_id"_key == compID or "auth_comp_id"_key == compID))
 			continue;
 
 		obsoleteChemComps.push_back(chemComp);
@@ -2719,7 +2719,7 @@ void structure::cleanup_empty_categories()
 	for (auto entity : entities)
 	{
 		std::string entityID = entity["id"].as<std::string>();
-		if (atomSite.exists("label_entity_id"_key == entityID))
+		if (atomSite.contains("label_entity_id"_key == entityID))
 			continue;
 
 		obsoleteEntities.push_back(entity);

src/parser.cpp

@@ -269,7 +269,7 @@ sac_parser::CIFToken sac_parser::get_next_token()
 {
 	const auto kEOF = std::char_traits<char>::eof();
 
-	CIFToken result = CIFToken::Unknown;
+	CIFToken result = CIFToken::UNKNOWN;
 	int quoteChar = 0;
 	State state = State::Start;
 	m_bol = false;
@@ -279,7 +279,7 @@ sac_parser::CIFToken sac_parser::get_next_token()
 
 	reserved_words_automaton dag;
 
-	while (result == CIFToken::Unknown)
+	while (result == CIFToken::UNKNOWN)
 	{
 		auto ch = get_next_char();
 
@@ -287,7 +287,7 @@ sac_parser::CIFToken sac_parser::get_next_token()
 		{
 			case State::Start:
 				if (ch == kEOF)
-					result = CIFToken::Eof;
+					result = CIFToken::END_OF_FILE;
 				else if (ch == '\n')
 				{
 					m_bol = true;
@@ -298,9 +298,9 @@ sac_parser::CIFToken sac_parser::get_next_token()
 				else if (ch == '#')
 					state = State::Comment;
 				else if (ch == '_')
-					state = State::Tag;
+					state = State::ItemName;
 				else if (ch == ';' and m_bol)
-					state = State::TextField;
+					state = State::TextItem;
 				else if (ch == '?')
 					state = State::QuestionMark;
 				else if (ch == '\'' or ch == '"')
@@ -316,7 +316,7 @@ sac_parser::CIFToken sac_parser::get_next_token()
 
 			case State::White:
 				if (ch == kEOF)
-					result = CIFToken::Eof;
+					result = CIFToken::END_OF_FILE;
 				else if (not is_space(ch))
 				{
 					state = State::Start;
@@ -335,7 +335,7 @@ sac_parser::CIFToken sac_parser::get_next_token()
 					m_token_buffer.clear();
 				}
 				else if (ch == kEOF)
-					result = CIFToken::Eof;
+					result = CIFToken::END_OF_FILE;
 				else if (not is_any_print(ch))
 					error("invalid character in comment");
 				break;
@@ -344,29 +344,29 @@ sac_parser::CIFToken sac_parser::get_next_token()
 				if (not is_non_blank(ch))
 				{
 					retract();
-					result = CIFToken::Value;
+					result = CIFToken::VALUE;
 				}
 				else
 					state = State::Value;
 				break;
 
-			case State::TextField:
+			case State::TextItem:
 				if (ch == '\n')
-					state = State::TextFieldNL;
+					state = State::TextItemNL;
 				else if (ch == kEOF)
 					error("unterminated textfield");
 				else if (not is_any_print(ch) and cif::VERBOSE > 2)
 					warning("invalid character in text field '" + std::string({static_cast<char>(ch)}) + "' (" + std::to_string((int)ch) + ")");
 				break;
 
-			case State::TextFieldNL:
+			case State::TextItemNL:
 				if (is_text_lead(ch) or ch == ' ' or ch == '\t')
-					state = State::TextField;
+					state = State::TextItem;
 				else if (ch == ';')
 				{
 					assert(m_token_buffer.size() >= 2);
 					m_token_value = std::string_view(m_token_buffer.data() + 1, m_token_buffer.size() - 3);
-					result = CIFToken::Value;
+					result = CIFToken::VALUE;
 				}
 				else if (ch == kEOF)
 					error("unterminated textfield");
@@ -387,7 +387,7 @@ sac_parser::CIFToken sac_parser::get_next_token()
 				if (is_white(ch))
 				{
 					retract();
-					result = CIFToken::Value;
+					result = CIFToken::VALUE;
 					if (m_token_buffer.size() < 2)
 						error("Invalid quoted string token");
 
@@ -403,11 +403,11 @@ sac_parser::CIFToken sac_parser::get_next_token()
 					error("invalid character in quoted string");
 				break;
 
-			case State::Tag:
+			case State::ItemName:
 				if (not is_non_blank(ch))
 				{
 					retract();
-					result = CIFToken::Tag;
+					result = CIFToken::ITEM_NAME;
 					m_token_value = std::string_view(m_token_buffer.data(), m_token_buffer.size());
 				}
 				break;
@@ -422,7 +422,7 @@ sac_parser::CIFToken sac_parser::get_next_token()
 						if (not is_non_blank(ch))
 						{
 							retract();
-							result = CIFToken::Value;
+							result = CIFToken::VALUE;
 							m_token_value = std::string_view(m_token_buffer.data(), m_token_buffer.size());
 						}
 						else
@@ -467,7 +467,7 @@ sac_parser::CIFToken sac_parser::get_next_token()
 				if (not is_non_blank(ch))
 				{
 					retract();
-					result = CIFToken::Value;
+					result = CIFToken::VALUE;
 					m_token_value = std::string_view(m_token_buffer.data(), m_token_buffer.size());
 					break;
 				}
@@ -483,7 +483,7 @@ sac_parser::CIFToken sac_parser::get_next_token()
 	if (VERBOSE >= 5)
 	{
 		std::cerr << get_token_name(result);
-		if (result != CIFToken::Eof)
+		if (result != CIFToken::END_OF_FILE)
 			std::cerr << " " << std::quoted(m_token_value);
 		std::cerr << '\n';
 	}
@@ -710,7 +710,7 @@ bool sac_parser::parse_single_datablock(const std::string &datablock, const data
 
 void sac_parser::parse_file()
 {
-	while (m_lookahead != CIFToken::Eof)
+	while (m_lookahead != CIFToken::END_OF_FILE)
 	{
 		switch (m_lookahead)
 		{
@@ -735,10 +735,10 @@ void sac_parser::parse_file()
 void sac_parser::parse_global()
 {
 	match(CIFToken::GLOBAL);
-	while (m_lookahead == CIFToken::Tag)
+	while (m_lookahead == CIFToken::ITEM_NAME)
 	{
-		match(CIFToken::Tag);
-		match(CIFToken::Value);
+		match(CIFToken::ITEM_NAME);
+		match(CIFToken::VALUE);
 	}
 }
 
@@ -747,7 +747,7 @@ void sac_parser::parse_datablock()
 	static const std::string kUnitializedCategory("<invalid>");
 	std::string cat = kUnitializedCategory;	// intial value acts as a guard for empty category names
 
-	while (m_lookahead == CIFToken::LOOP or m_lookahead == CIFToken::Tag or m_lookahead == CIFToken::SAVE_NAME)
+	while (m_lookahead == CIFToken::LOOP or m_lookahead == CIFToken::ITEM_NAME or m_lookahead == CIFToken::SAVE_NAME)
 	{
 		switch (m_lookahead)
 		{
@@ -757,12 +757,12 @@ void sac_parser::parse_datablock()
 
 				match(CIFToken::LOOP);
 
-				std::vector<std::string> tags;
+				std::vector<std::string> item_names;
 
-				while (m_lookahead == CIFToken::Tag)
+				while (m_lookahead == CIFToken::ITEM_NAME)
 				{
 					std::string catName, itemName;
-					std::tie(catName, itemName) = split_tag_name(m_token_value);
+					std::tie(catName, itemName) = split_item_name(m_token_value);
 
 					if (cat == kUnitializedCategory)
 					{
@@ -772,19 +772,19 @@ void sac_parser::parse_datablock()
 					else if (not iequals(cat, catName))
 						error("inconsistent categories in loop_");
 
-					tags.push_back(itemName);
+					item_names.push_back(itemName);
 
-					match(CIFToken::Tag);
+					match(CIFToken::ITEM_NAME);
 				}
 
-				while (m_lookahead == CIFToken::Value)
+				while (m_lookahead == CIFToken::VALUE)
 				{
 					produce_row();
 
-					for (auto tag : tags)
+					for (auto item_name : item_names)
 					{
-						produce_item(cat, tag, m_token_value);
-						match(CIFToken::Value);
+						produce_item(cat, item_name, m_token_value);
+						match(CIFToken::VALUE);
 					}
 				}
 
@@ -792,10 +792,10 @@ void sac_parser::parse_datablock()
 				break;
 			}
 
-			case CIFToken::Tag:
+			case CIFToken::ITEM_NAME:
 			{
 				std::string catName, itemName;
-				std::tie(catName, itemName) = split_tag_name(m_token_value);
+				std::tie(catName, itemName) = split_item_name(m_token_value);
 
 				if (not iequals(cat, catName))
 				{
@@ -804,11 +804,11 @@ void sac_parser::parse_datablock()
 					produce_row();
 				}
 
-				match(CIFToken::Tag);
+				match(CIFToken::ITEM_NAME);
 
 				produce_item(cat, itemName, m_token_value);
 
-				match(CIFToken::Value);
+				match(CIFToken::VALUE);
 				break;
 			}
 

src/pdb/pdb2cif.cpp

@@ -1123,9 +1123,6 @@ void PDBFileParser::PreParseInput(std::istream &is)
 	if (lookahead.back() == '\r')
 		lookahead.pop_back();
 
-	//	if (cif::starts_with(lookahead, "HEADER") == false)
-	//		throw std::runtime_error("This does not look like a PDB file, should start with a HEADER line");
-
 	auto contNr = [&lookahead](int offset, int len) -> int
 	{
 		std::string cs = lookahead.substr(offset, len);
@@ -1558,52 +1555,54 @@ void PDBFileParser::ParseTitle()
 	//	11 - 80       Specification   compound      Description of the molecular components.
 	//	              list
 
-	std::string value{ mRec->vS(11) };
-	if (value.find(':') == std::string::npos)
-	{
-		// special case for dumb, stripped files
-		auto &comp = GetOrCreateCompound(1);
-		comp.mInfo["MOLECULE"] = value;
-	}
-	else
-	{
-		SpecificationListParser p(value);
-
-		for (;;)
-		{
-			std::string key, val;
-			std::tie(key, val) = p.GetNextSpecification();
-
-			if (key.empty())
-				break;
-
-			if (not iequals(key, "MOL_ID") and mCompounds.empty())
-			{
-				if (cif::VERBOSE > 0)
-					std::cerr << "Ignoring invalid COMPND record\n";
-				break;
-			}
-
-			if (key == "MOL_ID")
-			{
-				auto &comp = GetOrCreateCompound(stoi(val));
-				comp.mTitle = title;
-			}
-			else if (key == "CHAIN")
-			{
-				for (auto c : cif::split<std::string>(val, ","))
-				{
-					cif::trim(c);
-					mCompounds.back().mChains.insert(c[0]);
-				}
-			}
-			else
-				mCompounds.back().mInfo[key] = val;
-		}
-	}
-
 	if (mRec->is("COMPND"))
+	{
+		std::string value{ mRec->vS(11) };
+		if (value.find(':') == std::string::npos)
+		{
+			// special case for dumb, stripped files
+			auto &comp = GetOrCreateCompound(1);
+			comp.mInfo["MOLECULE"] = value;
+		}
+		else
+		{
+			SpecificationListParser p(value);
+
+			for (;;)
+			{
+				std::string key, val;
+				std::tie(key, val) = p.GetNextSpecification();
+
+				if (key.empty())
+					break;
+
+				if (not iequals(key, "MOL_ID") and mCompounds.empty())
+				{
+					if (cif::VERBOSE > 0)
+						std::cerr << "Ignoring invalid COMPND record\n";
+					break;
+				}
+
+				if (key == "MOL_ID")
+				{
+					auto &comp = GetOrCreateCompound(stoi(val));
+					comp.mTitle = title;
+				}
+				else if (key == "CHAIN")
+				{
+					for (auto c : cif::split<std::string>(val, ","))
+					{
+						cif::trim(c);
+						mCompounds.back().mChains.insert(c[0]);
+					}
+				}
+				else
+					mCompounds.back().mInfo[key] = val;
+			}
+		}
+
 		GetNextRecord();
+	}
 
 	// SOURCE
 	Match("SOURCE", false);
@@ -1740,7 +1739,7 @@ void PDBFileParser::ParseTitle()
 		int n = 1;
 		cat = getCategory("audit_author");
 
-		value = { mRec->vS(11) };
+		std::string value = { mRec->vS(11) };
 		for (auto author : cif::split<std::string>(value, ",", true))
 		{
 			// clang-format off
@@ -3646,7 +3645,7 @@ void PDBFileParser::ConstructEntities()
 			PDBChain::AtomRes ar{ resName, resSeq, iCode };
 
 			if ((chain.mResiduesSeen.empty() or chain.mResiduesSeen.back() != ar) and
-				(cif::compound_factory::instance().is_known_peptide(resName) or cif::compound_factory::instance().is_known_base(resName)))
+				cif::compound_factory::instance().is_monomer(resName))
 			{
 				chain.mResiduesSeen.push_back(ar);
 			}
@@ -3731,11 +3730,8 @@ void PDBFileParser::ConstructEntities()
 			{
 				std::string resName = chain.mResiduesSeen[ix].mMonID;
 
-				if (cif::compound_factory::instance().is_known_peptide(resName) or
-					cif::compound_factory::instance().is_known_base(resName))
-				{
+				if (cif::compound_factory::instance().is_monomer(resName))
 					chain.mTerIndex = ix + 1;
-				}
 
 				InsertChemComp(resName);
 			}
@@ -3814,7 +3810,7 @@ void PDBFileParser::ConstructEntities()
 			int residueCount = (residuePerChainCounter[chainID] += 1);
 
 			// There appears to be a program that writes out HETATM records as ATOM records....
-			if (not(cif::compound_factory::instance().is_known_peptide(resName) or cif::compound_factory::instance().is_known_base(resName)) or
+			if (not cif::compound_factory::instance().is_monomer(resName) or
 				terminatedChains.count(chainID) or
 				(chain.mTerIndex > 0 and residueCount >= chain.mTerIndex))
 			{
@@ -4559,7 +4555,7 @@ void PDBFileParser::ConstructEntities()
 		std::string formula;
 		std::string type;
 		std::string nstd = ".";
-		std::string formulaWeight;
+		std::optional<float> formulaWeight;
 
 		if (compound != nullptr)
 		{
@@ -4570,7 +4566,7 @@ void PDBFileParser::ConstructEntities()
 				nstd = "y";
 
 			formula = compound->formula();
-			formulaWeight = std::to_string(compound->formula_weight());
+			formulaWeight = compound->formula_weight();
 		}
 
 		if (name.empty())
@@ -4597,7 +4593,7 @@ void PDBFileParser::ConstructEntities()
 			{ "id", cc },
 			{ "name", name },
 			{ "formula", formula },
-			{ "formula_weight", formulaWeight },
+			{ "formula_weight", formulaWeight, 3 },
 			{ "mon_nstd_flag", nstd },
 			{ "type", type }
 		});
@@ -4673,47 +4669,6 @@ void PDBFileParser::ConstructEntities()
 			}
 		}
 	}
-
-	// Finish by calculating the formula_weight for each entity
-	for (auto entity : *getCategory("entity"))
-	{
-		auto entity_id = entity["id"].as<std::string>();
-		float formula_weight = 0;
-
-		if (entity["type"] == "polymer")
-		{
-			int n = 0;
-
-			for (std::string comp_id : getCategory("pdbx_poly_seq_scheme")->find<std::string>(cif::key("entity_id") == entity_id, "mon_id"))
-			{
-				auto compound = cif::compound_factory::instance().create(comp_id);
-				assert(compound);
-				if (not compound)
-					throw std::runtime_error("missing information for compound " + comp_id);
-				formula_weight += compound->formula_weight();
-				++n;
-			}
-
-			formula_weight -= (n - 1) * 18.015;
-		}
-		else if (entity["type"] == "water")
-			formula_weight = 18.015;
-		else
-		{
-			auto comp_id = getCategory("pdbx_nonpoly_scheme")->find_first<std::optional<std::string>>(cif::key("entity_id") == entity_id, "mon_id");
-			if (comp_id.has_value())
-			{
-				auto compound = cif::compound_factory::instance().create(*comp_id);
-				assert(compound);
-				if (not compound)
-					throw std::runtime_error("missing information for compound " + *comp_id);
-				formula_weight = compound->formula_weight();
-			}
-		}
-
-		if (formula_weight > 0)
-			entity["formula_weight"] = formula_weight;
-	}
 }
 
 void PDBFileParser::ConstructSugarTrees(int &asymNr)
@@ -5581,31 +5536,6 @@ void PDBFileParser::ParseCrystallographic()
 
 		GetNextRecord();
 	}
-	else
-	{
-		// clang-format off
-
-		// no cryst1, make a simple one, like this:
-		// CRYST1    1.000    1.000    1.000  90.00  90.00  90.00 P 1           1
-		getCategory("cell")->emplace({
-			{ "entry_id", mStructureID }, //	 1 -  6       Record name   "CRYST1"
-			{ "length_a", 1 },            //	 7 - 15       Real(9.3)     a              a (Angstroms).
-			{ "length_b", 1 },            //	16 - 24       Real(9.3)     b              b (Angstroms).
-			{ "length_c", 1 },            //	25 - 33       Real(9.3)     c              c (Angstroms).
-			{ "angle_alpha", 90 },        //	34 - 40       Real(7.2)     alpha          alpha (degrees).
-			{ "angle_beta", 90 },         //	41 - 47       Real(7.2)     beta           beta (degrees).
-			{ "angle_gamma", 90 },        //	48 - 54       Real(7.2)     gamma          gamma (degrees).
-			/* goes into symmetry */      //	56 - 66       LString       sGroup         Space  group.
-			{ "Z_PDB", 1 }                //	67 - 70       Integer       z              Z value.
-		});
-
-		getCategory("symmetry")->emplace({
-			{ "entry_id", mStructureID },
-			{ "space_group_name_H-M", "P 1" },
-			{ "Int_Tables_number", 1 }
-		});
-		// clang-format on
-	}
 }
 
 void PDBFileParser::ParseCoordinateTransformation()
@@ -6466,7 +6396,12 @@ file read(std::istream &is)
 		// and so the very first character in a valid PDB file
 		// is 'H'. It is as simple as that.
 
-		if (ch == 'h' or ch == 'H')
+		// Well, not quite, Unfortunately... People insisted that
+		// having only ATOM records also makes up a valid PDB file...
+		// Since mmCIF files cannot validly start with a letter character
+		// apart from the letter 'd', the test has changed into the following:
+
+		if (std::isalpha(ch) and std::toupper(ch) != 'D')
 			read_pdb_file(is, result);
 		else
 		{
@@ -6478,11 +6413,11 @@ file read(std::istream &is)
 			{
 				std::throw_with_nested(std::runtime_error("Since the file did not start with a valid PDB HEADER line mmCIF was assumed, but that failed."));
 			}
-
-			// Since we're using the cif::pdb way of reading the file, the data may need
-			// reconstruction
-			reconstruct_pdbx(result);
 		}
+
+		// Since we're using the cif::pdb way of reading the file, the data may need
+		// reconstruction
+		reconstruct_pdbx(result);
 	}
 
 	// Must be a PDB like file, right?

src/pdb/pdb2cif_remark_3.cpp

@@ -1493,8 +1493,8 @@ bool Remark3Parser::parse(const std::string &expMethod, PDBRecord *r, cif::datab
 					auto r1 = cat1.front();
 					auto r2 = cat2.front();
 
-					for (auto column : cat1.key_fields())
-						r2[column] = r1[column].text();
+					for (auto item : cat1.key_items())
+						r2[item] = r1[item].text();
 				}
 			}
 			else

src/pdb/validate-pdbx.cpp

@@ -69,26 +69,65 @@ condition get_parents_condition(const validator &validator, row_handle rh, const
 
 bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 {
-	using namespace cif::literals;
+	std::error_code ec;
+	bool result = is_valid_pdbx_file(file, dictionary, ec);
+	return result and ec == std::errc();
+}
 
-	auto &cf = cif::compound_factory::instance();
-	auto &validator = cif::validator_factory::instance().operator[](dictionary);
+bool is_valid_pdbx_file(const file &file, std::error_code &ec)
+{
+	bool result = false;
+
+	if (file.empty())
+		ec = make_error_code(validation_error::empty_file);
+	else
+	{
+		std::string dictionary = "mmcif_pdbx";
+
+		for (auto &db : file)
+		{
+			auto audit_conform = db.get("audit_conform");
+			if (audit_conform == nullptr)
+				continue;
+			
+			if (not audit_conform->empty())
+			{
+				auto specified_dict = audit_conform->front()["dict_name"];
+				if (not specified_dict.empty())
+					dictionary = specified_dict.as<std::string>();
+			}
+
+			break;
+		}
+
+		result = is_valid_pdbx_file(file, dictionary, ec);
+	}
+	
+	return result;
+}
+
+bool is_valid_pdbx_file(const file &file, std::string_view dictionary, std::error_code &ec)
+{
+	using namespace cif::literals;
 
 	bool result = true;
 
 	try
 	{
+		auto &cf = cif::compound_factory::instance();
+		auto &validator = cif::validator_factory::instance().operator[](dictionary);
+
 		if (file.empty())
-			throw validation_error("Empty file");
+			throw std::runtime_error("Empty file");
 
 		auto &db = file.front();
 
 		if (db.empty())
-			throw validation_error("Empty datablock");
+			throw std::runtime_error("Empty datablock");
 
 		auto &atom_site = db["atom_site"];
 		if (atom_site.empty())
-			throw validation_error("Empty or missing atom_site category");
+			throw std::runtime_error("Empty or missing atom_site category");
 
 		auto &pdbx_poly_seq_scheme = db["pdbx_poly_seq_scheme"];
 
@@ -106,34 +145,38 @@ bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 			last_seq_id = *seq_id;
 
 			auto comp_id = r.get<std::string>("label_comp_id");
-			if (not cf.is_known_peptide(comp_id))
+			if (not cf.is_monomer(comp_id))
 				continue;
 
 			auto p = pdbx_poly_seq_scheme.find(get_parents_condition(validator, r, pdbx_poly_seq_scheme));
 			if (p.size() != 1)
-				throw validation_error("For each residue in atom_site that is a residue in a polymer there should be exactly one pdbx_poly_seq_scheme record");
+			{
+				if (cif::VERBOSE > 0)
+					std::clog << "In atom_site record: " << r["id"].text() << '\n';
+				throw std::runtime_error("For each monomer in atom_site there should be exactly one pdbx_poly_seq_scheme record");
+			}
 		}
 
 		auto &entity = db["entity"];
 		if (entity.empty())
-			throw validation_error("Entity category is missing or empty");
+			throw std::runtime_error("Entity category is missing or empty");
 
 		auto &entity_poly = db["entity_poly"];
 		if (entity_poly.empty())
-			throw validation_error("Entity_poly category is missing or empty");
+			throw std::runtime_error("Entity_poly category is missing or empty");
 
 		auto &entity_poly_seq = db["entity_poly_seq"];
 		if (entity_poly_seq.empty())
-			throw validation_error("Entity_poly_seq category is missing or empty");
+			throw std::runtime_error("Entity_poly_seq category is missing or empty");
 
 		auto &struct_asym = db["struct_asym"];
 		if (struct_asym.empty())
-			throw validation_error("struct_asym category is missing or empty");
+			throw std::runtime_error("struct_asym category is missing or empty");
 
 		for (auto entity_id : entity.find<std::string>("type"_key == "polymer", "id"))
 		{
 			if (entity_poly.count("entity_id"_key == entity_id) != 1)
-				throw validation_error("There should be exactly one entity_poly record per polymer entity");
+				throw std::runtime_error("There should be exactly one entity_poly record per polymer entity");
 
 			const auto entity_poly_type = entity_poly.find1<std::string>("entity_id"_key == entity_id, "type");
 
@@ -151,7 +194,7 @@ bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 							"seq_id"_key == num and
 							"hetero"_key == hetero) != 1)
 					{
-						throw validation_error("For each entity_poly_seq record there should be exactly one pdbx_poly_seq record");
+						throw std::runtime_error("For each entity_poly_seq record there should be exactly one pdbx_poly_seq record");
 					}
 				}
 			}
@@ -163,11 +206,11 @@ bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 						"num"_key == seq_id and
 						"hetero"_key == hetero) != 1)
 				{
-					throw validation_error("For each pdbx_poly_seq/struct_asym record there should be exactly one entity_poly_seq record");
+					throw std::runtime_error("For each pdbx_poly_seq/struct_asym record there should be exactly one entity_poly_seq record");
 				}
 
 				if ((mon_per_seq_id[seq_id].size() > 1) != hetero)
-					throw validation_error("Mismatch between the hetero flag in the poly seq schemes and the number residues per seq_id");
+					throw std::runtime_error("Mismatch between the hetero flag in the poly seq schemes and the number residues per seq_id");
 			}
 
 			for (const auto &[seq_id, mon_ids] : mon_per_seq_id)
@@ -183,8 +226,8 @@ bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 						"label_asym_id"_key == asym_id and
 						"label_seq_id"_key == seq_id and not std::move(cond);
 					
-					if (atom_site.exists(std::move(cond)))
-						throw validation_error("An atom_site record exists that has no parent in the poly seq scheme categories");
+					if (atom_site.contains(std::move(cond)))
+						throw std::runtime_error("An atom_site record exists that has no parent in the poly seq scheme categories");
 				}
 			}
 
@@ -205,13 +248,12 @@ bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 					for (auto comp_id : comp_ids)
 					{
 						std::string letter;
-						if (cf.is_known_base(comp_id))
-							letter = compound_factory::kBaseMap.at(comp_id);
-						else if (cf.is_known_peptide(comp_id))
-							letter = compound_factory::kAAMap.at(comp_id);
-						else
+
+						if (can)
 						{
-							if (can)
+							if (compound_factory::kBaseMap.contains(comp_id))
+								letter = compound_factory::kBaseMap.at(comp_id);
+							else
 							{
 								auto c = cf.create(comp_id);
 								if (c and c->one_letter_code())
@@ -219,6 +261,13 @@ bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 								else
 									letter = "X";
 							}
+						}
+						else
+						{
+							if (compound_factory::kAAMap.contains(comp_id))
+								letter = compound_factory::kAAMap.at(comp_id);
+							else if (comp_id.length() == 1 and compound_factory::kBaseMap.contains(comp_id))
+								letter = compound_factory::kBaseMap.at(comp_id);
 							else
 								letter = '(' + comp_id + ')';
 						}
@@ -250,7 +299,7 @@ bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 				seq->erase(std::remove_if(seq->begin(), seq->end(), [](char ch) { return std::isspace(ch); }), seq->end());
 
 				if (not seq_match(false, seq->begin(), seq->end()))
-					throw validation_error("Sequences do not match for entity " + entity_id);
+					throw std::runtime_error("Sequences do not match for entity " + entity_id);
 			}
 
 			if (not seq_can.has_value())
@@ -261,11 +310,10 @@ bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 			else
 			{
 				seq_can->erase(std::remove_if(seq_can->begin(), seq_can->end(), [](char ch) { return std::isspace(ch); }), seq_can->end());
-				
+
 				if (not seq_match(true, seq_can->begin(), seq_can->end()))
-					throw validation_error("Canonical sequences do not match for entity " + entity_id);
+					throw std::runtime_error("Canonical sequences do not match for entity " + entity_id);
 			}
-			
 		}
 
 		result = true;
@@ -275,8 +323,12 @@ bool is_valid_pdbx_file(const file &file, std::string_view dictionary)
 		result = false;
 		if (cif::VERBOSE > 0)
 			std::clog << ex.what() << '\n';
+		ec = make_error_code(validation_error::not_valid_pdbx);
 	}
 
+	if (not result and ec == std::errc())
+		ec = make_error_code(validation_error::not_valid_pdbx);
+
 	return result;
 }
 

src/row.cpp

@@ -29,44 +29,44 @@
 namespace cif
 {
 
-void row_handle::assign(uint16_t column, std::string_view value, bool updateLinked, bool validate)
+void row_handle::assign(uint16_t item, std::string_view value, bool updateLinked, bool validate)
 {
 	if (not m_category)
 		throw std::runtime_error("uninitialized row");
 
-	m_category->update_value(m_row, column, value, updateLinked, validate);
+	m_category->update_value(m_row, item, value, updateLinked, validate);
 }
 
-uint16_t row_handle::get_column_ix(std::string_view name) const
+uint16_t row_handle::get_item_ix(std::string_view name) const
 {
 	if (not m_category)
 		throw std::runtime_error("uninitialized row");
 
-	return m_category->get_column_ix(name);
+	return m_category->get_item_ix(name);
 }
 
-std::string_view row_handle::get_column_name(uint16_t ix) const
+std::string_view row_handle::get_item_name(uint16_t ix) const
 {
 	if (not m_category)
 		throw std::runtime_error("uninitialized row");
 
-	return m_category->get_column_name(ix);
+	return m_category->get_item_name(ix);
 }
 
-uint16_t row_handle::add_column(std::string_view name)
+uint16_t row_handle::add_item(std::string_view name)
 {
 	if (not m_category)
 		throw std::runtime_error("uninitialized row");
 
-	return m_category->add_column(name);
+	return m_category->add_item(name);
 }
 
-void row_handle::swap(uint16_t column, row_handle &b)
+void row_handle::swap(uint16_t item, row_handle &b)
 {
 	if (not m_category)
 		throw std::runtime_error("uninitialized row");
 
-	m_category->swap_item(column, *this, b);
+	m_category->swap_item(item, *this, b);
 }
 
 // --------------------------------------------------------------------
@@ -86,7 +86,7 @@ row_initializer::row_initializer(row_handle rh)
 		auto &i = r->operator[](ix);
 		if (not i)
 			continue;
-		emplace_back(cat.get_column_name(ix), i.text());
+		emplace_back(cat.get_item_name(ix), i.text());
 	}
 }
 

src/text.cpp

@@ -35,24 +35,24 @@ namespace cif
 // --------------------------------------------------------------------
 // This really makes a difference, having our own tolower routines
 
-const uint8_t kCharToLowerMap[256] =
-	{
-		0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
-		0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
-		0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
-		0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
-		0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
-		0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
-		0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
-		0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
-		0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
-		0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
-		0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
-		0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
-		0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
-		0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
-		0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
-		0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff};
+const uint8_t kCharToLowerMap[256] = {
+	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
+	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
+	0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
+	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
+	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
+	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
+	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
+	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
+	0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
+	0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
+	0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
+	0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
+	0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
+	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
+};
 
 // --------------------------------------------------------------------
 
@@ -171,7 +171,7 @@ std::string trim_right_copy(std::string_view s)
 		e = pe;
 	}
 
-	return {s.begin(), e};
+	return { s.begin(), e };
 }
 
 std::string trim_left_copy(std::string_view s)
@@ -185,27 +185,46 @@ std::string trim_left_copy(std::string_view s)
 		b = std::next(b);
 	}
 
-	return {b, s.end()};
+	return { b, s.end() };
 }
 
 void trim_left(std::string &s)
 {
-	auto b = s.begin();
-	while (b != s.end())
+	auto in = s.begin(), out = s.begin();
+
+	while (in != s.end() and std::isspace(*in))
+		++in;
+	
+	if (in == s.end())
+		s.clear();
+	else if (in != out)
 	{
-		if (not std::isspace(*b))
-			break;
-
-		b = std::next(b);
+		while (in != s.end())
+			*out++ = *in++;
+		s.erase(out, s.end());
 	}
-
-	s.erase(s.begin(), b);
 }
 
 void trim(std::string &s)
 {
-	trim_right(s);
-	trim_left(s);
+	auto in = s.begin(), out = s.begin(), end = s.end();
+
+	while (end != s.begin() and std::isspace(*(end - 1)))
+		--end;
+
+	while (in != end and std::isspace(*in))
+		++in;
+	
+	if (in == end)
+		s.clear();
+	else if (in != out)
+	{
+		while (in != end)
+			*out++ = *in++;
+		s.erase(out, s.end());
+	}
+	else if (end != s.end())
+		s.erase(end, s.end());
 }
 
 std::string trim_copy(std::string_view s)
@@ -215,19 +234,19 @@ std::string trim_copy(std::string_view s)
 
 // --------------------------------------------------------------------
 
-std::tuple<std::string, std::string> split_tag_name(std::string_view tag)
+std::tuple<std::string, std::string> split_item_name(std::string_view item_name)
 {
-	if (tag.empty())
-		throw std::runtime_error("empty tag");
-	if (tag[0] != '_')
-		throw std::runtime_error("tag '" + std::string { tag } + "' does not start with underscore");
+	if (item_name.empty())
+		throw std::runtime_error("empty item_name");
+	if (item_name[0] != '_')
+		throw std::runtime_error("item_name '" + std::string{ item_name } + "' does not start with underscore");
 
-	auto s = tag.find('.');
+	auto s = item_name.find('.');
 	if (s == std::string::npos)
-		// throw std::runtime_error("tag does not contain dot (" + std::string{ tag } + ')');
-		return std::tuple<std::string, std::string>{ "", tag.substr(1) };
+		// throw std::runtime_error("item_name does not contain dot (" + std::string{ item_name } + ')');
+		return std::tuple<std::string, std::string>{ "", item_name.substr(1) };
 	else
-		return std::tuple<std::string, std::string>{tag.substr(1, s - 1), tag.substr(s + 1)};
+		return std::tuple<std::string, std::string>{ item_name.substr(1, s - 1), item_name.substr(s + 1) };
 }
 
 // --------------------------------------------------------------------
@@ -242,8 +261,7 @@ std::string cif_id_for_number(int number)
 		result += static_cast<char>('A' + r);
 
 		number = (number - r) / 26 - 1;
-	}
-	while (number >= 0);
+	} while (number >= 0);
 
 	std::reverse(result.begin(), result.end());
 
@@ -298,29 +316,29 @@ enum LineBreakClass
 	kLBC_Unknown
 };
 
-const LineBreakClass kASCII_LBTable[128] =
-	{
-		kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark,
-		kLBC_CombiningMark, kLBC_BreakAfter, kLBC_LineFeed, kLBC_MandatoryBreak, kLBC_MandatoryBreak, kLBC_CarriageReturn, kLBC_CombiningMark, kLBC_CombiningMark,
-		kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark,
-		kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark,
-		kLBC_Space, kLBC_Exlamation, kLBC_Quotation, kLBC_Alphabetic, kLBC_PrefixNumeric, kLBC_PostfixNumeric, kLBC_Alphabetic, kLBC_Quotation,
-		kLBC_OpenPunctuation, kLBC_CloseParenthesis, kLBC_Alphabetic, kLBC_PrefixNumeric,
+const LineBreakClass kASCII_LBTable[128] = {
+	kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark,
+	kLBC_CombiningMark, kLBC_BreakAfter, kLBC_LineFeed, kLBC_MandatoryBreak, kLBC_MandatoryBreak, kLBC_CarriageReturn, kLBC_CombiningMark, kLBC_CombiningMark,
+	kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark,
+	kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark, kLBC_CombiningMark,
+	kLBC_Space, kLBC_Exlamation, kLBC_Quotation, kLBC_Alphabetic, kLBC_PrefixNumeric, kLBC_PostfixNumeric, kLBC_Alphabetic, kLBC_Quotation,
+	kLBC_OpenPunctuation, kLBC_CloseParenthesis, kLBC_Alphabetic, kLBC_PrefixNumeric,
 
-		// comma treated differently here, it is not a numeric separator in PDB
-		kLBC_SymbolAllowingBreakAfter /*	kLBC_InfixNumericSeparator */,
+	// comma treated differently here, it is not a numeric separator in PDB
+	kLBC_SymbolAllowingBreakAfter /*	kLBC_InfixNumericSeparator */,
 
-		kLBC_Hyphen, kLBC_InfixNumericSeparator, kLBC_SymbolAllowingBreakAfter,
-		kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric,
-		kLBC_Numeric, kLBC_Numeric, kLBC_InfixNumericSeparator, kLBC_InfixNumericSeparator, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Exlamation,
-		kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
-		kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
-		kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
-		kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_OpenPunctuation, kLBC_PrefixNumeric, kLBC_CloseParenthesis, kLBC_Alphabetic, kLBC_Alphabetic,
-		kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
-		kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
-		kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
-		kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_OpenPunctuation, kLBC_BreakAfter, kLBC_ClosePunctuation, kLBC_Alphabetic, kLBC_CombiningMark};
+	kLBC_Hyphen, kLBC_InfixNumericSeparator, kLBC_SymbolAllowingBreakAfter,
+	kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric, kLBC_Numeric,
+	kLBC_Numeric, kLBC_Numeric, kLBC_InfixNumericSeparator, kLBC_InfixNumericSeparator, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Exlamation,
+	kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
+	kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
+	kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
+	kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_OpenPunctuation, kLBC_PrefixNumeric, kLBC_CloseParenthesis, kLBC_Alphabetic, kLBC_Alphabetic,
+	kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
+	kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
+	kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic,
+	kLBC_Alphabetic, kLBC_Alphabetic, kLBC_Alphabetic, kLBC_OpenPunctuation, kLBC_BreakAfter, kLBC_ClosePunctuation, kLBC_Alphabetic, kLBC_CombiningMark
+};
 
 std::string::const_iterator nextLineBreak(std::string::const_iterator text, std::string::const_iterator end)
 {
@@ -338,33 +356,33 @@ std::string::const_iterator nextLineBreak(std::string::const_iterator text, std:
 
 	const breakAction brkTable[27][27] = {
 		//        OP   CL   CP   QU   GL   NS   EX   SY   IS   PR   PO   NU   AL   ID   IN   HY   BA   BB   B2   ZW   CM   WJ   H2   H3   JL   JV   JT
-		/* OP */ {PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, CPB, PBK, PBK, PBK, PBK, PBK, PBK},
-		/* CL */ {DBK, PBK, PBK, IBK, IBK, PBK, PBK, PBK, PBK, IBK, IBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* CP */ {DBK, PBK, PBK, IBK, IBK, PBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* QU */ {PBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK},
-		/* GL */ {IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK},
-		/* NS */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* EX */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* SY */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* IS */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* PR */ {IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, IBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK},
-		/* PO */ {IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* NU */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* AL */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* ID */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* IN */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* HY */ {DBK, PBK, PBK, IBK, DBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* BA */ {DBK, PBK, PBK, IBK, DBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* BB */ {IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK},
-		/* B2 */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, PBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* ZW */ {DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK},
-		/* CM */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK},
-		/* WJ */ {IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK},
-		/* H2 */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, IBK, IBK},
-		/* H3 */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, IBK},
-		/* JL */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, DBK},
-		/* JV */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, IBK, IBK},
-		/* JT */ {DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, IBK},
+		/* OP */ { PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, PBK, CPB, PBK, PBK, PBK, PBK, PBK, PBK },
+		/* CL */ { DBK, PBK, PBK, IBK, IBK, PBK, PBK, PBK, PBK, IBK, IBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* CP */ { DBK, PBK, PBK, IBK, IBK, PBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* QU */ { PBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK },
+		/* GL */ { IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK },
+		/* NS */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* EX */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* SY */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* IS */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* PR */ { IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, IBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK },
+		/* PO */ { IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* NU */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* AL */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* ID */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* IN */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* HY */ { DBK, PBK, PBK, IBK, DBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* BA */ { DBK, PBK, PBK, IBK, DBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* BB */ { IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK },
+		/* B2 */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, IBK, IBK, DBK, PBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* ZW */ { DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK, PBK, DBK, DBK, DBK, DBK, DBK, DBK, DBK },
+		/* CM */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, DBK, IBK, IBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, DBK },
+		/* WJ */ { IBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, IBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, IBK },
+		/* H2 */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, IBK, IBK },
+		/* H3 */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, IBK },
+		/* JL */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, IBK, IBK, IBK, IBK, DBK },
+		/* JV */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, IBK, IBK },
+		/* JT */ { DBK, PBK, PBK, IBK, IBK, IBK, PBK, PBK, PBK, DBK, IBK, DBK, DBK, DBK, IBK, IBK, IBK, DBK, DBK, PBK, CIB, PBK, DBK, DBK, DBK, DBK, IBK },
 	};
 
 	uint8_t ch = static_cast<uint8_t>(*text);
@@ -418,7 +436,7 @@ std::string::const_iterator nextLineBreak(std::string::const_iterator text, std:
 std::vector<std::string> wrapLine(const std::string &text, size_t width)
 {
 	std::vector<std::string> result;
-	std::vector<size_t> offsets = {0};
+	std::vector<size_t> offsets = { 0 };
 
 	auto b = text.begin();
 	while (b != text.end())

src/validate.cpp

@@ -39,16 +39,33 @@
 // the code will use boost::regex instead.
 
 #if USE_BOOST_REGEX
-#include <boost/regex.hpp>
+# include <boost/regex.hpp>
 using boost::regex;
 #else
-#include <regex>
+# include <regex>
 using std::regex;
 #endif
 
 namespace cif
 {
 
+validation_exception::validation_exception(std::error_code ec)
+	: runtime_error(ec.message())
+{
+}
+
+validation_exception::validation_exception(std::error_code ec, std::string_view category)
+	: runtime_error((ec.message() + "; category: ").append(category))
+{
+}
+
+validation_exception::validation_exception(std::error_code ec, std::string_view category, std::string_view item)
+	: runtime_error((ec.message() + "; category: ").append(category).append("; item: ").append(item))
+{
+}
+
+// --------------------------------------------------------------------
+
 struct regex_impl : public regex
 {
 	regex_impl(std::string_view rx)
@@ -57,21 +74,12 @@ struct regex_impl : public regex
 	}
 };
 
-validation_error::validation_error(const std::string &msg)
-	: m_msg(msg)
-{
-}
-
-validation_error::validation_error(const std::string &cat, const std::string &item, const std::string &msg)
-	: m_msg("When validating _" + cat + '.' + item + ": " + msg)
-{
-}
-
 // --------------------------------------------------------------------
 
-DDL_PrimitiveType map_to_primitive_type(std::string_view s)
+DDL_PrimitiveType map_to_primitive_type(std::string_view s, std::error_code &ec) noexcept
 {
-	DDL_PrimitiveType result;
+	ec = {};
+	DDL_PrimitiveType result = DDL_PrimitiveType::Char;
 	if (iequals(s, "char"))
 		result = DDL_PrimitiveType::Char;
 	else if (iequals(s, "uchar"))
@@ -79,7 +87,16 @@ DDL_PrimitiveType map_to_primitive_type(std::string_view s)
 	else if (iequals(s, "numb"))
 		result = DDL_PrimitiveType::Numb;
 	else
-		throw validation_error("Not a known primitive type");
+		ec = make_error_code(validation_error::not_a_known_primitive_type);
+	return result;
+}
+
+DDL_PrimitiveType map_to_primitive_type(std::string_view s)
+{
+	std::error_code ec;
+	auto result = map_to_primitive_type(s, ec);
+	if (ec)
+		throw std::system_error(ec, std::string{ s });
 	return result;
 }
 
@@ -196,63 +213,72 @@ int type_validator::compare(std::string_view a, std::string_view b) const
 
 // --------------------------------------------------------------------
 
-// void ValidateItem::addLinked(ValidateItem* parent, const std::string& parentItem, const std::string& childItem)
-//{
-////	if (mParent != nullptr and VERBOSE)
-////		cerr << "replacing parent in " << mCategory->m_name << " from " << mParent->mCategory->m_name << " to " << parent->mCategory->m_name << endl;
-////	mParent = parent;
-//
-//	if (m_type == nullptr and parent != nullptr)
-//		m_type = parent->m_type;
-//
-//	if (parent != nullptr)
-//	{
-//		mLinked.push_back({parent, parentItem, childItem});
-//
-//		parent->mChildren.insert(this);
-////
-////		if (mCategory->mKeys == std::vector<std::string>{mTag})
-////			parent->mForeignKeys.insert(this);
-//	}
-//}
-
 void item_validator::operator()(std::string_view value) const
 {
+	std::error_code ec;
+	if (not validate_value(value, ec))
+		throw std::system_error(ec, std::string{ value } + " does not match rx for " + m_item_name);
+}
+
+bool item_validator::validate_value(std::string_view value, std::error_code &ec) const noexcept
+{
+	ec = {};
+
 	if (not value.empty() and value != "?" and value != ".")
 	{
 		if (m_type != nullptr and not regex_match(value.begin(), value.end(), *m_type->m_rx))
-			throw validation_error(m_category->m_name, m_tag, "Value '" + std::string{ value } + "' does not match type expression for type " + m_type->m_name);
-
-		if (not m_enums.empty())
-		{
-			if (m_enums.count(std::string{ value }) == 0)
-				throw validation_error(m_category->m_name, m_tag, "Value '" + std::string{ value } + "' is not in the list of allowed values");
-		}
+			ec = make_error_code(validation_error::value_does_not_match_rx);
+		else if (not m_enums.empty() and m_enums.count(std::string{ value }) == 0)
+			ec = make_error_code(validation_error::value_is_not_in_enumeration_list);
 	}
+
+	return ec == std::errc();
 }
 
 // --------------------------------------------------------------------
 
-void category_validator::addItemValidator(item_validator &&v)
+void category_validator::add_item_validator(item_validator &&v)
 {
 	if (v.m_mandatory)
-		m_mandatory_fields.insert(v.m_tag);
+		m_mandatory_items.insert(v.m_item_name);
 
 	v.m_category = this;
 
 	auto r = m_item_validators.insert(std::move(v));
 	if (not r.second and VERBOSE >= 4)
-		std::cout << "Could not add validator for item " << v.m_tag << " to category " << m_name << '\n';
+		std::cout << "Could not add validator for item " << v.m_item_name << " to category " << m_name << '\n';
 }
 
-const item_validator *category_validator::get_validator_for_item(std::string_view tag) const
+const item_validator *category_validator::get_validator_for_item(std::string_view item_name) const
 {
 	const item_validator *result = nullptr;
-	auto i = m_item_validators.find(item_validator{ std::string(tag) });
+	auto i = m_item_validators.find(item_validator{ std::string(item_name) });
 	if (i != m_item_validators.end())
 		result = &*i;
 	else if (VERBOSE > 4)
-		std::cout << "No validator for tag " << tag << '\n';
+		std::cout << "No validator for item " << item_name << '\n';
+	return result;
+}
+
+const item_validator *category_validator::get_validator_for_aliased_item(std::string_view item_name) const
+{
+	const item_validator *result = nullptr;
+
+	for (auto &iv : m_item_validators)
+	{
+		for (auto &ai : iv.m_aliases)
+		{
+			const auto &[cat, name] = split_item_name(ai.m_name);
+			if (iequals(name, item_name) and iequals(cat, m_name))
+			{
+				result = &iv;
+				break;
+			}
+		}
+		if (result)
+			break;
+	}
+
 	return result;
 }
 
@@ -295,19 +321,19 @@ const category_validator *validator::get_validator_for_category(std::string_view
 	return result;
 }
 
-item_validator *validator::get_validator_for_item(std::string_view tag) const
+item_validator *validator::get_validator_for_item(std::string_view item_name) const
 {
 	item_validator *result = nullptr;
 
 	std::string cat, item;
-	std::tie(cat, item) = split_tag_name(tag);
+	std::tie(cat, item) = split_item_name(item_name);
 
 	auto *cv = get_validator_for_category(cat);
 	if (cv != nullptr)
 		result = const_cast<item_validator *>(cv->get_validator_for_item(item));
 
 	if (result == nullptr and VERBOSE > 4)
-		std::cout << "No validator for item " << tag << '\n';
+		std::cout << "No validator for item " << item_name << '\n';
 
 	return result;
 }
@@ -332,11 +358,11 @@ void validator::add_link_validator(link_validator &&v)
 		auto piv = pcv->get_validator_for_item(v.m_parent_keys[i]);
 
 		if (piv == nullptr)
-			throw std::runtime_error("unknown parent tag _" + v.m_parent_category + '.' + v.m_parent_keys[i]);
+			throw std::runtime_error("unknown parent item _" + v.m_parent_category + '.' + v.m_parent_keys[i]);
 
 		auto civ = ccv->get_validator_for_item(v.m_child_keys[i]);
 		if (civ == nullptr)
-			throw std::runtime_error("unknown child tag _" + v.m_child_category + '.' + v.m_child_keys[i]);
+			throw std::runtime_error("unknown child item _" + v.m_child_category + '.' + v.m_child_keys[i]);
 
 		if (civ->m_type == nullptr and piv->m_type != nullptr)
 			const_cast<item_validator *>(civ)->m_type = piv->m_type;
@@ -351,7 +377,7 @@ std::vector<const link_validator *> validator::get_links_for_parent(std::string_
 
 	for (auto &l : m_link_validators)
 	{
-		if (l.m_parent_category == category)
+		if (iequals(l.m_parent_category, category))
 			result.push_back(&l);
 	}
 
@@ -364,19 +390,32 @@ std::vector<const link_validator *> validator::get_links_for_child(std::string_v
 
 	for (auto &l : m_link_validators)
 	{
-		if (l.m_child_category == category)
+		if (iequals(l.m_child_category, category))
 			result.push_back(&l);
 	}
 
 	return result;
 }
 
-void validator::report_error(const std::string &msg, bool fatal) const
+void validator::report_error(std::error_code ec, bool fatal) const
 {
 	if (m_strict or fatal)
-		throw validation_error(msg);
-	else if (VERBOSE > 0)
-		std::cerr << msg << '\n';
+		throw validation_exception(ec);
+	else
+		std::cerr << ec.message() << '\n';
+}
+
+void validator::report_error(std::error_code ec, std::string_view category,
+	std::string_view item, bool fatal) const
+{
+	auto ex = item.empty() ?
+		validation_exception(ec, category) :
+		validation_exception(ec, category, item);
+
+	if (m_strict or fatal)
+		throw ex;
+	else
+		std::cerr << ex.what() << '\n';
 }
 
 // --------------------------------------------------------------------
@@ -438,12 +477,12 @@ const validator &validator_factory::operator[](std::string_view dictionary_name)
 			if (not std::filesystem::exists(p, ec) or ec)
 			{
 				for (const char *dir : {
-#if defined(CACHE_DIR)
+# if defined(CACHE_DIR)
 						 CACHE_DIR,
-#endif
-#if defined(DATA_DIR)
+# endif
+# if defined(DATA_DIR)
 							 DATA_DIR
-#endif
+# endif
 					 })
 				{
 					auto p2 = std::filesystem::path(dir) / p;

test/CMakeLists.txt

@@ -0,0 +1,72 @@
+# We're using the older version 2 of Catch2
+
+find_package(Catch2 QUIET)
+
+if(NOT Catch2_FOUND)
+	FetchContent_Declare(
+		Catch2
+		GIT_REPOSITORY https://github.com/catchorg/Catch2.git
+		GIT_TAG v2.13.9)
+
+	FetchContent_MakeAvailable(Catch2)
+
+	set(Catch2_VERSION "2.13.9")
+endif()
+
+list(
+	APPEND
+	CIFPP_tests
+	unit-v2
+	unit-3d
+	format
+	model
+	rename-compound
+	sugar
+	spinner
+	reconstruction
+	validate-pdbx)
+
+add_library(test-main OBJECT "${CMAKE_CURRENT_SOURCE_DIR}/test-main.cpp")
+
+target_link_libraries(test-main cifpp::cifpp Catch2::Catch2)
+
+if(${Catch2_VERSION} VERSION_GREATER_EQUAL 3.0.0)
+	target_compile_definitions(test-main PUBLIC CATCH22=0)
+else()
+	target_compile_definitions(test-main PUBLIC CATCH22=1)
+endif()
+
+foreach(CIFPP_TEST IN LISTS CIFPP_tests)
+	set(CIFPP_TEST "${CIFPP_TEST}-test")
+	set(CIFPP_TEST_SOURCE "${CMAKE_CURRENT_SOURCE_DIR}/${CIFPP_TEST}.cpp")
+
+	add_executable(
+		${CIFPP_TEST} ${CIFPP_TEST_SOURCE} $<TARGET_OBJECTS:test-main>)
+
+	if(${Catch2_VERSION} VERSION_GREATER_EQUAL 3.0.0)
+		target_compile_definitions(${CIFPP_TEST} PUBLIC CATCH22=0)
+	else()
+		target_compile_definitions(${CIFPP_TEST} PUBLIC CATCH22=1)
+	endif()
+
+	target_link_libraries(${CIFPP_TEST} PRIVATE Threads::Threads cifpp::cifpp
+		Catch2::Catch2)
+	target_include_directories(${CIFPP_TEST} PRIVATE "${EIGEN_INCLUDE_DIR}")
+
+	if(MSVC)
+		# Specify unwind semantics so that MSVC knowns how to handle exceptions
+		target_compile_options(${CIFPP_TEST} PRIVATE /EHsc)
+	endif()
+
+	add_custom_target(
+		"run-${CIFPP_TEST}"
+		DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/Run${CIFPP_TEST}.touch ${CIFPP_TEST})
+
+	add_custom_command(
+		OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/Run${CIFPP_TEST}.touch
+		COMMAND $<TARGET_FILE:${CIFPP_TEST}> --data-dir
+		${CMAKE_CURRENT_SOURCE_DIR})
+
+	add_test(NAME ${CIFPP_TEST} COMMAND $<TARGET_FILE:${CIFPP_TEST}> --data-dir
+		${CMAKE_CURRENT_SOURCE_DIR})
+endforeach()

test/format-test.cpp

@@ -24,7 +24,8 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <catch2/catch.hpp>
+
+#include "test-main.hpp"
 
 #include <stdexcept>
 

test/model-test.cpp

@@ -26,8 +26,6 @@
 
 #include "test-main.hpp"
 
-#include <catch2/catch.hpp>
-
 #include <stdexcept>
 
 #include <cif++.hpp>

test/reconstruction-test.cpp

@@ -0,0 +1,62 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ * 
+ * Copyright (c) 2024 NKI/AVL, Netherlands Cancer Institute
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "test-main.hpp"
+
+#include <cif++.hpp>
+
+#include <iostream>
+#include <fstream>
+
+TEST_CASE("reconstruct")
+{
+	cif::compound_factory::instance().push_dictionary(gTestDir / "REA.cif");
+
+	for (std::filesystem::directory_iterator i(gTestDir / "reconstruct"); i != std::filesystem::directory_iterator{}; ++i)
+	{
+		std::cout << i->path() << '\n';
+
+		if (i->path().extension() == ".pdb")
+		{
+			cif::file f = cif::pdb::read(i->path());
+
+			std::error_code ec;
+
+			if (not cif::pdb::is_valid_pdbx_file(f, ec))
+				CHECK(cif::pdb::reconstruct_pdbx(f));
+		}
+		else
+		{
+			cif::file f(i->path());
+
+			std::error_code ec;
+			CHECK_FALSE(cif::pdb::is_valid_pdbx_file(f, ec));
+			CHECK(ec != std::errc{});
+
+			CHECK(cif::pdb::reconstruct_pdbx(f));
+		}
+	}
+}

test/rename-compound-test.cpp

@@ -28,8 +28,6 @@
 
 #include <cif++.hpp>
 
-#include <catch2/catch.hpp>
-
 #include <iostream>
 #include <fstream>
 

test/spinner-test.cpp

@@ -1,6 +1,32 @@
-#include "cif++/utilities.hpp"
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ * 
+ * Copyright (c) 2024 NKI/AVL, Netherlands Cancer Institute
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
 
-#include <catch2/catch.hpp>
+#include "test-main.hpp"
+
+#include "cif++/utilities.hpp"
 
 #include <random>
 #include <thread>

test/sugar-test.cpp

@@ -26,8 +26,6 @@
 
 #include "test-main.hpp"
 
-#include <catch2/catch.hpp>
-
 #include <stdexcept>
 
 #include <cif++.hpp>

test/test-main.cpp

@@ -1,10 +1,9 @@
+#define CATCH_CONFIG_RUNNER 1
+
 #include "test-main.hpp"
 
 #include <cif++.hpp>
 
-#define CATCH_CONFIG_RUNNER
-#include <catch2/catch.hpp>
-
 std::filesystem::path gTestDir = std::filesystem::current_path();
 
 int main(int argc, char *argv[])
@@ -12,7 +11,13 @@ int main(int argc, char *argv[])
 	Catch::Session session; // There must be exactly one instance
 
 	// Build a new parser on top of Catch2's
+#if CATCH22
 	using namespace Catch::clara;
+#else
+	// Build a new parser on top of Catch2's
+	using namespace Catch::Clara;
+#endif
+
 	auto cli = session.cli()                               // Get Catch2's command line parser
 	           | Opt(gTestDir, "data-dir")                 // bind variable to a new option, with a hint string
 	                 ["-D"]["--data-dir"]                  // the option names it will respond to

test/test-main.hpp

@@ -1,3 +1,37 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ * 
+ * Copyright (c) 2024 NKI/AVL, Netherlands Cancer Institute
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#if CATCH22
+#include <catch2/catch.hpp>
+#else
+#include <catch2/catch_all.hpp>
+#endif
+
 #include <filesystem>
 
 extern std::filesystem::path gTestDir;

test/unit-3d-test.cpp

@@ -26,8 +26,6 @@
 
 #include "test-main.hpp"
 
-#include <catch2/catch.hpp>
-
 #include <stdexcept>
 
 #include <cif++.hpp>

test/unit-v2-test.cpp

@@ -26,8 +26,6 @@
 
 #include "test-main.hpp"
 
-#include <catch2/catch.hpp>
-
 #include <cif++.hpp>
 
 #include "cif++/dictionary_parser.hpp"
@@ -568,7 +566,7 @@ _test.value
 	auto &test = db["test"];
 	REQUIRE(test.size() == 5);
 
-	REQUIRE(test.exists("value"_key == cif::null));
+	REQUIRE(test.contains("value"_key == cif::null));
 	REQUIRE(test.find("value"_key == cif::null).size() == 2);
 }
 
@@ -746,27 +744,51 @@ _cat_2.desc
 	std::istream is_data(&data_buffer);
 	f.load(is_data);
 
-	auto &cat1 = f.front()["cat_1"];
-	auto &cat2 = f.front()["cat_2"];
+	SECTION("one")
+	{
+		auto &cat1 = f.front()["cat_1"];
+		auto &cat2 = f.front()["cat_2"];
 
-	REQUIRE(cat1.size() == 3);
-	REQUIRE(cat2.size() == 3);
+		REQUIRE(cat1.size() == 3);
+		REQUIRE(cat2.size() == 3);
 
-	cat1.erase(cif::key("id") == 1);
+		cat1.erase(cif::key("id") == 1);
 
-	REQUIRE(cat1.size() == 2);
-	REQUIRE(cat2.size() == 1);
+		REQUIRE(cat1.size() == 2);
+		REQUIRE(cat2.size() == 1);
 
-	// REQUIRE_THROWS_AS(cat2.emplace({
-	//     { "id", 4 },
-	//     { "parent_id", 4 },
-	//     { "desc", "moet fout gaan" }
-	// }), std::exception);
+		// REQUIRE_THROWS_AS(cat2.emplace({
+		//     { "id", 4 },
+		//     { "parent_id", 4 },
+		//     { "desc", "moet fout gaan" }
+		// }), std::exception);
 
-	REQUIRE_THROWS_AS(cat2.emplace({ { "id", "vijf" }, // <- invalid value
-						  { "parent_id", 2 },
-						  { "desc", "moet fout gaan" } }),
-		std::exception);
+		REQUIRE_THROWS_AS(cat2.emplace({ { "id", "vijf" }, // <- invalid value
+							{ "parent_id", 2 },
+							{ "desc", "moet fout gaan" } }),
+			std::exception);
+	}
+
+	// SECTION("two")
+	// {
+	// 	auto &cat1 = f.front()["cat_1"];
+	// 	auto &cat2 = f.front()["cat_2"];
+
+	// 	cat1.update_value(cif::all(), "id", [](std::string_view v) -> std::string
+	// 	{
+	// 		int vi;
+	// 		auto [ec, ptr] = std::from_chars(v.data(), v.data() + v.length(), vi);
+	// 		return std::to_string(vi + 1);
+	// 	});
+
+	// 	REQUIRE(cat1.find1<std::string>(cif::key("id") == 2, "name") == "Aap");
+	// 	REQUIRE(cat1.find1<std::string>(cif::key("id") == 3, "name") == "Noot");
+	// 	REQUIRE(cat1.find1<std::string>(cif::key("id") == 4, "name") == "Mies");
+
+	// 	REQUIRE(cat2.find1<int>(cif::key("id") == 1, "parent_id") == 2);
+	// 	REQUIRE(cat2.find1<int>(cif::key("id") == 2, "parent_id") == 2);
+	// 	REQUIRE(cat2.find1<int>(cif::key("id") == 3, "parent_id") == 3);
+	// }
 }
 
 // --------------------------------------------------------------------
@@ -3486,4 +3508,11 @@ TEST_CASE("pdb2cif_formula_weight")
 
 	fw = a.front()["entity"].find1<float>(cif::key("id") == 3, "formula_weight");
 	CHECK(fw == 18.015f);
+}
+
+// --------------------------------------------------------------------
+
+TEST_CASE("update_values_with_provider")
+{
+
 }

test/validate-pdbx-test.cpp

@@ -26,8 +26,6 @@
 
 #include "test-main.hpp"
 
-#include <catch2/catch.hpp>
-
 #include <cif++.hpp>
 
 #include <stdexcept>