AnyMap.h

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//! @file AnyMap.h
 
// This file is part of Cantera. See License.txt in the top-level directory or
// at https://cantera.org/license.txt for license and copyright information.
 
#ifndef CT_ANYMAP_H
#define CT_ANYMAP_H
 
#include "cantera/base/ct_defs.h"
#include "cantera/base/ctexceptions.h"
#include "cantera/base/Units.h"
 
#include <unordered_map>
#include <filesystem>
#include <any>
 
namespace YAML
{
class Emitter;
Emitter& operator<<(Emitter& out, const Cantera::AnyMap& rhs);
Emitter& operator<<(Emitter& out, const Cantera::AnyValue& rhs);
}
 
namespace Cantera
{
 
//! @defgroup anyGroup Generic Containers
//! Generic containers for storing data of any type.
//! @ingroup ioGroup
 
//! Base class defining common data possessed by both AnyMap and AnyValue
//! objects.
//! @ingroup anyGroup
class AnyBase {
public:
    AnyBase() = default;
    AnyBase(const AnyBase& other) = default;
    virtual ~AnyBase() = default;
    AnyBase& operator=(const AnyBase& other);
 
    //! For values which are derived from an input file, set the line and column
    //! of this value in that file. Used for providing context for some error
    //! messages.
    void setLoc(int line, int column);
 
    //! Get a value from the metadata applicable to the AnyMap tree containing
    //! this node.
    const AnyValue& getMetadata(const string& key) const;
 
protected:
    //! The line where this value occurs in the input file. Set to -1 for values
    //! that weren't created from an input file.
    int m_line = -1;
 
    //! If m_line >= 0, the column where this value occurs in the input file.
    //! If m_line == -1, a value used for determining output ordering
    int m_column = 0;
 
    //! Metadata relevant to an entire AnyMap tree, such as information about
    // the input file used to create it
    shared_ptr<AnyMap> m_metadata;
 
    friend class InputFileError;
    friend void warn_deprecated(const string& source, const AnyBase& node,
                                const string& message);
};
 
class AnyMap;
 
//! A wrapper for a variable whose type is determined at runtime
/*!
 * Instances of AnyValue are used as values in an AnyMap. Values are converted
 * to a concrete type using the templated as() method or convenience methods
 * such as asString() and asDouble(). See AnyMap for usage examples.
 *
 * Elements are set using assignment, and the assignment operator has been
 * overloaded for specific types so that only those types are allowed to be
 * used in an AnyValue. The allowed types are:
 * - `AnyMap`
 * - `double`
 * - `long int`
 * - `bool`
 * - `string`
 * - `vector` of any of the above
 * @ingroup anyGroup
 */
class AnyValue : public AnyBase
{
public:
    AnyValue();
    ~AnyValue();
 
    bool operator==(const AnyValue& other) const;
    bool operator!=(const AnyValue& other) const;
 
    //! If this AnyValue is an AnyMap, return the value stored in `key`.
    AnyValue& operator[](const string& key);
    const AnyValue& operator[](const string& key) const;
 
    //! Returns `true` if this AnyValue is an AnyMap and that map contains
    //! a key with the given name.
    bool hasKey(const string& key) const;
 
    //! Set the name of the key storing this value in an AnyMap. Used for
    //! providing informative error messages in class InputFileError.
    void setKey(const string& key);
 
    //! Propagate metadata to any child elements
    void propagateMetadata(shared_ptr<AnyMap>& file);
 
    //! Get the value of this key as the specified type.
    template<class T>
    const T& as() const;
 
    template<class T>
    T& as();
 
    //! Returns the type of the held value.
    const std::type_info& type() const;
 
    //! Returns a string specifying the type of the held value.
    string type_str() const;
 
    //! Return boolean indicating whether AnyValue is empty.
    bool empty() const;
 
    //! Returns `true` if the held value is of the specified type.
    template<class T>
    bool is() const;
 
    //! Returns `true` if the held value is a vector of the specified type, such as
    //! `vector<double>`.
    //! @since New in %Cantera 3.0.
    template<class T>
    bool isVector() const;
 
    //! Returns `true` if the held value is a matrix of the specified type and a
    //! consistent number of columns, such as `vector<vector<double>>`. If the
    //! number of columns is provided, a match is required.
    //! @since New in %Cantera 3.0.
    template<class T>
    bool isMatrix(size_t cols=npos) const;
 
    //! Returns `true` if the held value is a scalar type (such as `double`,
    //! `long int`, `string`, or `bool`).
    bool isScalar() const;
 
    //! Returns size of the held vector.
    //! If not a vector or the type is not supported npos is returned.
    //! Types considered include `vector<double>`, `vector<long int>`, `vector<string>`,
    //! and `vector<bool`.
    //! @since New in %Cantera 3.0.
    size_t vectorSize() const;
 
    //! Returns rows and columns of a matrix.
    //! If the number of columns is not consistent, the number of columns is set to
    //! npos; if the type is not supported, a npos pair is returned.
    //! Types considered include `vector<vector<double>>`, `vector<vector<long int>>`,
    //! `vector<vector<string>>` and `vector<vector<bool>>`.
    //! @since New in %Cantera 3.0.
    pair<size_t, size_t> matrixShape() const;
 
    explicit AnyValue(const string& value);
    explicit AnyValue(const char* value);
    AnyValue& operator=(const string& value);
    AnyValue& operator=(const char* value);
    //! Return the held value, if it is a string
    const string& asString() const;
    bool operator==(const string& other) const;
    bool operator!=(const string& other) const;
    friend bool operator==(const string& lhs, const AnyValue& rhs);
    friend bool operator!=(const string& lhs, const AnyValue& rhs);
 
    //! @name Quantity conversions
    //! Assign a quantity consisting of one or more values and their
    //! corresponding units, which will be converted to a target unit system
    //! when the applyUnits() function is later called on the root of the
    //! AnyMap.
    //! @{
 
    //! Assign a scalar quantity with units as a string, for example
    //! `{3.0, "m^2"}`. If the `is_act_energy` flag is set to `true`, the units
    //! will be converted using the special rules for activation energies.
    void setQuantity(double value, const string& units, bool is_act_energy=false);
 
    //! Assign a scalar quantity with units as a Units object, for cases where
    //! the units vary and are determined dynamically, such as reaction
    //! pre-exponential factors
    void setQuantity(double value, const Units& units);
 
    //! Assign a vector where all the values have the same units
    void setQuantity(const vector<double>& values, const string& units);
 
    typedef function<void(AnyValue&, const UnitSystem&)> unitConverter;
 
    //! Assign a value of any type where the unit conversion requires a
    //! different behavior besides scaling all values by the same factor
    void setQuantity(const AnyValue& value, const unitConverter& converter);
    //! @} end group quantity conversions
 
    explicit AnyValue(double value);
    AnyValue& operator=(double value);
    //! Return the held value as a `double`, if it is a `double` or a `long int`.
    double& asDouble();
    const double& asDouble() const;
    bool operator==(const double& other) const;
    bool operator!=(const double& other) const;
    friend bool operator==(const double& lhs, const AnyValue& rhs);
    friend bool operator!=(const double& lhs, const AnyValue& rhs);
 
    explicit AnyValue(bool value);
    AnyValue& operator=(bool value);
    //! Return the held value, if it is a `bool`.
    bool& asBool();
    const bool& asBool() const;
 
    explicit AnyValue(long int value);
    explicit AnyValue(int value);
    AnyValue& operator=(long int value);
    AnyValue& operator=(int value);
    //! Return the held value, if it is a `long int`.
    long int& asInt();
    const long int& asInt() const;
    bool operator==(const long int& other) const;
    bool operator!=(const long int& other) const;
    bool operator==(const int& other) const;
    bool operator!=(const int& other) const;
    friend bool operator==(const long int& lhs, const AnyValue& rhs);
    friend bool operator!=(const long int& lhs, const AnyValue& rhs);
    friend bool operator==(const int& lhs, const AnyValue& rhs);
    friend bool operator!=(const int& lhs, const AnyValue& rhs);
 
    template<class T>
    AnyValue& operator=(const vector<T>& value);
    //! Return the held value, if it is a vector of type `T`. If called with one
    //! argument, requires the vector to be of the specified size. If called
    //! with two arguments, requires the vector to be within the range specified
    //! by the two values, inclusive.
    template<class T>
    const vector<T>& asVector(size_t nMin=npos, size_t nMax=npos) const;
    template<class T>
    vector<T>& asVector(size_t nMin=npos, size_t nMax=npos);
 
    explicit AnyValue(const AnyMap& value);
    AnyValue& operator=(const AnyMap& value);
    AnyValue& operator=(AnyMap&& value);
 
    template<class T>
    AnyValue& operator=(const std::unordered_map<string, T> items);
 
    template<class T>
    AnyValue& operator=(const map<string, T> items);
 
    //! @see AnyMap::exclude()
    static AnyValue exclude();
 
    //! Return the held `AnyMap` as a `map` where all of the values have
    //! the specified type.
    template<class T>
    map<string, T> asMap() const;
 
    //! Access a `vector<AnyMap>` as a mapping using the value of `name` from
    //! each item as the key in the new mapping.
    /*!
     * For example, for the list:
     * ```
     * [{name: O2, weight: 32}, {name: CH4, weight: 16}]
     * ```
     * calling `asMap("name")` will create a map with keys ``O2`` and ``CH4``.
     */
    std::unordered_map<string, const AnyMap*> asMap(const string& name) const;
    std::unordered_map<string, AnyMap*> asMap(const string& name);
 
    //! Treating the value as `vector<AnyMap>`, return the item where the given
    //! key has the specified value.
    /*!
     * If value is the empty string, returns the first item in the list.
     *
     * If the contained type is just `AnyMap` rather than `vector<AnyMap>`, it
     * will be treated as a vector of length 1.
     *
     * If the value does not exist but the `create` flag is set to true, a new
     * map with that key and value will be created and returned.
     */
    AnyMap& getMapWhere(const string& key, const string& value, bool create=false);
    const AnyMap& getMapWhere(const string& key, const string& value) const;
 
    //! Returns `true` when getMapWhere() would succeed
    bool hasMapWhere(const string& key, const string& value) const;
 
    //! Return values used to determine the sort order when outputting to YAML
    pair<int, int> order() const;
 
    //! See AnyMap::applyUnits()
    void applyUnits(shared_ptr<UnitSystem>& units);
 
    //! See AnyMap::setFlowStyle()
    void setFlowStyle(bool flow=true);
 
private:
    template<class T>
    void checkSize(const vector<T>& v, size_t nMin, size_t nMax) const;
 
    //! Key of this value in a parent `AnyMap`
    string m_key;
 
    //! The held value
    std::any m_value;
 
    typedef bool (*Comparer)(const std::any&, const std::any&);
 
    //! Equality comparison function used when *lhs* is of type *T*
    template <typename T>
    static bool eq_comparer(const std::any& lhs, const std::any& rhs);
 
    //! Helper function for comparing vectors of different (but comparable)
    //! types, for example `vector<double>` and `vector<long int>`
    template<class T, class U>
    static bool vector_eq(const std::any& lhs, const std::any& rhs);
 
    //! Helper function for comparing nested vectors of different (but
    //! comparable) types, for example `vector<vector<double>>` and
    //! `vector<vector<long int>>`
    template<class T, class U>
    static bool vector2_eq(const std::any& lhs, const std::any& rhs);
 
    mutable Comparer m_equals;
 
    friend YAML::Emitter& YAML::operator<<(YAML::Emitter& out, const AnyValue& rhs);
};
 
//! Implicit conversion to vector<AnyValue>
template<>
const vector<AnyValue>& AnyValue::asVector<AnyValue>(size_t nMin, size_t nMax) const;
 
template<>
vector<AnyValue>& AnyValue::asVector<AnyValue>(size_t nMin, size_t nMax);
 
//! Implicit conversion of long int to double if accessed as a vector<double>
template<>
const vector<double>& AnyValue::asVector<double>(size_t nMin, size_t nMax) const;
 
template<>
vector<double>& AnyValue::asVector<double>(size_t nMin, size_t nMax);
 
//! Implicit conversion of long int to double if accessed as a vector<vector<double>>
template<>
const vector<vector<double>>& AnyValue::asVector<vector<double>>(size_t nMin,
                                                                 size_t nMax) const;
 
template<>
vector<vector<double>>& AnyValue::asVector<vector<double>>(size_t nMin, size_t nMax);
 
//! Implicit conversion of AnyMap to a vector<AnyMap> of length 1, or an empty
//! vector<AnyValue> an empty vector<AnyMap>
template<>
const vector<AnyMap>& AnyValue::asVector<AnyMap>(size_t nMin, size_t nMax) const;
 
template<>
vector<AnyMap>& AnyValue::asVector<AnyMap>(size_t nMin, size_t nMax);
 
//! A map of string keys to values whose type can vary at runtime
/*!
 * Values in an AnyMap are held by instances of AnyValue. Instances of AnyMap
 * can be nested to form a tree.
 *
 * ## Setting elements
 *
 * ```
 * AnyMap breakfast;
 * breakfast["spam"] = 123.4; // Creates a value of type 'double'
 * breakfast["eggs"] = "scrambled"; // Creates a value of type 'string'
 *
 * // Create a nested AnyMap named "beans" which has a key named "baked"
 * // whose value is a vector<double>
 * vector<double> v{3.14, 1.59, 2.65};
 * breakfast["beans"]["baked"] = v;
 *
 * // Create a nested AnyMap with values of the same type
 * map<string, double> breads{{"wheat", 4.0}, {"white", 2.5}};
 * breakfast["toast"] = breads;
 * // Equivalent to:
 * breakfast["toast"]["wheat"] = 4.0
 * breakfast["toast"]["white"] = 2.5
 * ```
 *
 * ## Accessing elements
 *
 * ```
 * double val1 = breakfast["spam"].asDouble();
 * string val2 = breakfast["eggs"].asString();
 * vector<double> val3 = breakfast["beans"]["baked"].asVector<double>();
 *
 * map<string, double> = breakfast["toast"].asMap<double>();
 * ```
 *
 * ## Checking for elements
 *
 * ```
 * try {
 *     breakfast["waffle"].asDouble();
 * } except (std::exception& err) {
 *     // Exception will be thrown.
 *     // 'breakfast' will have an empty key named 'waffle' unless 'breakfast'
 *     // is a 'const AnyMap'.
 * }
 *
 * try {
 *     breakfast.at("grits").asDouble();
 * } except (std::exception& err) {
 *     // Exception will be thrown and no new key will be added
 * }
 *
 * if (breakfast.hasKey("grits")) {
 *     // do something with this entry
 * }
 * ```
 *
 * ## Checking element types
 *
 * ```
 * if (breakfast["sausage"].is<vector<double>>()) {
 *     // access using asVector<double>
 * } else if (breakfast["sausage"].type() == typeid(vector<string>)) {
 *     // access using asVector<string>
 * }
 * ```
 * @ingroup anyGroup
 */
class AnyMap : public AnyBase
{
public:
    AnyMap();
 
    //! Create an AnyMap from a YAML file.
    /*!
     *  Searches the directory containing the optionally-specified parent file
     *  first, followed by the current working directory and the %Cantera include
     *  path.
     */
    static AnyMap fromYamlFile(const string& name,
                               const string& parent_name="");
 
    //! Create an AnyMap from a string containing a YAML document
    static AnyMap fromYamlString(const string& yaml);
 
    string toYamlString() const;
 
    //! Get the value of the item stored in `key`.
    AnyValue& operator[](const string& key);
    const AnyValue& operator[](const string& key) const;
 
    //! Used to create a new item which will be populated from a YAML input
    //! string, where the item with `key` occurs at the specified line and
    //! column within the string.
    AnyValue& createForYaml(const string& key, int line, int column);
 
    //! Get the value of the item stored in `key`. Raises an exception if the
    //! value does not exist.
    const AnyValue& at(const string& key) const;
 
    //! Return boolean indicating whether AnyMap is empty.
    bool empty() const;
 
    //! Returns `true` if the map contains an item named `key`.
    bool hasKey(const string& key) const;
 
    //! Erase the value held by `key`.
    void erase(const string& key);
 
    //! Erase all items in the mapping
    void clear();
 
    //! Add items from `other` to this AnyMap. If keys in `other` also exist in
    //! this AnyMap, the `keepExisting` option determines which item is used.
    //! Local units defined in `other` are not retained.
    void update(const AnyMap& other, bool keepExisting=true);
 
    //! Mark `key` as excluded from this map. This prevents `key` from being added
    //! by update(). Explicitly setting a value for `key` overrides this exclusion.
    void exclude(const string& key);
 
    //! Return a string listing the keys in this AnyMap, for use in error
    //! messages, for example
    string keys_str() const;
 
    //! Return an unordered set of keys
    //! @since New in %Cantera 3.0.
    set<string> keys() const;
 
    //! Set a metadata value that applies to this AnyMap and its children.
    //! Mainly for internal use in reading or writing from files.
    void setMetadata(const string& key, const AnyValue& value);
 
    //! Copy metadata including input line/column from an existing AnyMap
    void copyMetadata(const AnyMap& other);
 
    //! Propagate metadata to any child elements
    void propagateMetadata(shared_ptr<AnyMap>& file);
 
    //! If `key` exists, return it as a `bool`, otherwise return `default_`.
    bool getBool(const string& key, bool default_) const;
 
    //! If `key` exists, return it as a `long int`, otherwise return `default_`.
    long int getInt(const string& key, long int default_) const;
 
    //! If `key` exists, return it as a `double`, otherwise return `default_`.
    double getDouble(const string& key, double default_) const;
 
    //! If `key` exists, return it as a `string`, otherwise return `default_`.
    const string& getString(const string& key,
                            const string& default_) const;
 
    //! Convert the item stored by the given `key` to the units specified in
    //! `units`. If the stored value is a double, convert it using the default
    //! units. If the input is a string, treat this as a dimensioned value, such
    //! as '988 kg/m^3' and convert from the specified units.
    double convert(const string& key, const string& units) const;
    double convert(const string& key, const Units& units) const;
 
    //! Convert the item stored by the given `key` to the units specified in
    //! `units`. If the stored value is a double, convert it using the default
    //! units. If the input is a string, treat this as a dimensioned value, such
    //! as '988 kg/m^3' and convert from the specified units. If the key is
    //! missing, the `default_` value is returned.
    double convert(const string& key, const string& units,
                   double default_) const;
 
    //! Convert a vector of dimensional values
    /*!
     * For each item in the vector, if the stored value is a double, convert it
     * using the default units. If the value is a string, treat it as a
     * dimensioned value, such as '988 kg/m^3', and convert from the specified
     * units.
     *
     * @param key    Location of the vector in this AnyMap
     * @param units  Units to convert to
     * @param nMin   Minimum allowed length of the vector. If `nMax` is not
     *     specified, this is also taken to be the maximum length. An exception
     *     is thrown if this condition is not met.
     * @param nMax   Maximum allowed length of the vector. An exception is
     *     thrown if this condition is not met.
     */
    vector<double> convertVector(const string& key, const string& units,
                                 size_t nMin=npos, size_t nMax=npos) const;
 
    //! Defined to allow use with range-based for loops. Iteration automatically
    //! skips over keys that start and end with double underscores.
    class Iterator {
    public:
        Iterator() {}
        Iterator(const std::unordered_map<string, AnyValue>::const_iterator& start,
                 const std::unordered_map<string, AnyValue>::const_iterator& stop);
 
        const pair<const string, AnyValue>& operator*() const {
            return *m_iter;
        }
        const pair<const string, AnyValue>* operator->() const {
            return &*m_iter;
        }
        bool operator!=(const Iterator& right) const {
            return m_iter != right.m_iter;
        }
        Iterator& operator++();
 
    private:
        std::unordered_map<string, AnyValue>::const_iterator m_iter;
        std::unordered_map<string, AnyValue>::const_iterator m_stop;
    };
 
    //! Defined to allow use with range-based for loops
    Iterator begin() const {
        return Iterator(m_data.begin(), m_data.end());
    }
 
    //! Defined to allow use with range-based for loops
    Iterator end() const {
        return Iterator(m_data.end(), m_data.end());
    }
 
    class OrderedIterator;
 
    //! Proxy for iterating over an AnyMap in the defined output ordering.
    //! See ordered().
    class OrderedProxy {
    public:
        OrderedProxy() {}
        OrderedProxy(const AnyMap& data, bool withUnits);
        OrderedIterator begin() const;
        OrderedIterator end() const;
 
        typedef vector<pair<
            pair<int, int>,
            const pair<const string, AnyValue>*>> OrderVector;
    private:
        const AnyMap* m_data;
        OrderVector m_ordered;
        unique_ptr<pair<const string, AnyValue>> m_units;
    };
 
    //! Defined to allow the OrderedProxy class to be used with range-based
    //! for loops.
    class OrderedIterator {
    public:
        OrderedIterator() {}
        OrderedIterator(const AnyMap::OrderedProxy::OrderVector::const_iterator& start,
                        const AnyMap::OrderedProxy::OrderVector::const_iterator& stop);
 
        const pair<const string, AnyValue>& operator*() const {
            return *m_iter->second;
        }
        const pair<const string, AnyValue>* operator->() const {
            return &(*m_iter->second);
        }
        bool operator!=(const OrderedIterator& right) const {
            return m_iter != right.m_iter;
        }
        OrderedIterator& operator++() { ++m_iter; return *this; }
 
    private:
        OrderedProxy::OrderVector::const_iterator m_iter;
        OrderedProxy::OrderVector::const_iterator m_stop;
    };
 
    //! Return a proxy object that allows iteration in an order determined by the order
    //! of insertion, the location in an input file, and rules specified by the
    //! addOrderingRules() method. The `withUnits` flag determines whether to include a
    //! `units` directive, if any local units are defined (for use by the YAML emitter).
    OrderedProxy ordered(bool withUnits=false) const {
        return OrderedProxy(*this, withUnits);
    }
 
    //! Returns the number of elements in this map
    size_t size() const;
 
    bool operator==(const AnyMap& other) const;
    bool operator!=(const AnyMap& other) const;
 
    //! Return the default units that should be used to convert stored values
    const UnitSystem& units() const { return *m_units; }
 
    //! @copydoc units()
    shared_ptr<UnitSystem> unitsShared() const { return m_units; }
 
    //! Use the supplied UnitSystem to set the default units, and recursively
    //! process overrides from nodes named `units`.
    /*!
     * If a `units` node is present in a map that contains other keys, the
     * specified units are taken to be the defaults for that map. If the map
     * contains only a `units` node, and is the first item in a list of maps,
     * then the specified units are taken to be the defaults for all the maps in
     * the list.
     *
     * After being processed, the `units` nodes are removed. This function is
     * called automatically by the fromYamlFile() and fromYamlString()
     * constructors.
     *
     * @warning This function is an experimental part of the %Cantera API and
     *     may be changed or removed without notice.
     */
    void applyUnits();
 
    //! See applyUnits()
    void applyUnits(shared_ptr<UnitSystem>& units);
 
    //! Set the unit system for this AnyMap. The applyUnits() method should be
    //! called on the root AnyMap object after all desired calls to setUnits()
    //! in the tree have been made.
    void setUnits(const UnitSystem& units);
 
    //! Use "flow" style when outputting this AnyMap to YAML
    void setFlowStyle(bool flow=true);
 
    //! Add global rules for setting the order of elements when outputting
    //! AnyMap objects to YAML
    /*!
     * Enables specifying keys that should appear at either the beginning
     * or end of the generated YAML mapping. Only programmatically-added keys
     * are rearranged. Keys which come from YAML input retain their existing
     * ordering, and are output after programmatically-added keys. Keys are
     * output in the order provided to this method.
     *
     * This function should be called exactly once for any given spec that
     * is to be added. To facilitate this, the method returns a bool so that
     * it can be called as part of initializing a static variable. To avoid
     * spurious compiler warnings about unused variables, the following
     * structure can be used:
     *
     * ```
     * static bool reg = AnyMap::addOrderingRules("Reaction",
     *         {{"head", "equation"}, {"tail", "duplicate"}});
     * if (reg) {
     *     reactionMap["__type__"] = "Reaction";
     * }
     * ```
     *
     * @param objectType  Apply rules to maps where the hidden `__type__` key
     *     has the corresponding value.
     * @param specs       A list of rule specifications. Each rule consists of
     *     two strings. The first string is either "head" or "tail", and the
     *     second string is the name of a key
     * @returns  ``true``, to facilitate static initialization
     */
    static bool addOrderingRules(const string& objectType,
                                 const vector<vector<string>>& specs);
 
    //! Remove the specified file from the input cache if it is present
    static void clearCachedFile(const string& filename);
 
private:
    //! The stored data
    std::unordered_map<string, AnyValue> m_data;
 
    //! The default units that are used to convert stored values
    shared_ptr<UnitSystem> m_units;
 
    //! Cache for previously-parsed input (YAML) files. The key is the full path
    //! to the file, and the second element of the value is the last-modified
    //! time for the file, which is used to enable change detection.
    static std::unordered_map<string,
                              pair<AnyMap, std::filesystem::file_time_type>> s_cache;
 
    //! Information about fields that should appear first when outputting to
    //! YAML. Keys in this map are matched to `__type__` keys in AnyMap
    //! objects, and values are a list of field names.
    static std::unordered_map<string, vector<string>> s_headFields;
 
    //! Information about fields that should appear last when outputting to
    //! YAML. Keys in this map are matched to `__type__` keys in AnyMap
    //! objects, and values are a list of field names.
    static std::unordered_map<string, vector<string>> s_tailFields;
 
    friend class AnyValue;
    friend YAML::Emitter& YAML::operator<<(YAML::Emitter& out, const AnyMap& rhs);
};
 
// Define begin() and end() to allow use with range-based for loops
AnyMap::Iterator begin(const AnyValue& v);
AnyMap::Iterator end(const AnyValue& v);
 
//! Error thrown for problems processing information contained in an AnyMap or
//! AnyValue.
/*!
 *  This class uses the file, line, and column information stored in an AnyMap
 *  or AnyValue to provide an error message including context lines for the
 *  original user input.
 */
class InputFileError : public CanteraError
{
public:
    //! Indicate an error occurring in `procedure` while using information from
    //! `node`. The `message` and `args` are processed as in the CanteraError
    //! class.
    template <typename... Args>
    InputFileError(const string& procedure, const AnyBase& node,
                   const string& message, const Args&... args)
        : CanteraError(
            procedure,
            formatError(
                (sizeof...(args) == 0) ? message
                                       : fmt::format(fmt::runtime(message), args...),
                node.m_line, node.m_column, node.m_metadata))
        {
        }
 
    //! Indicate an error occurring in `procedure` while using information from
    //! `node1` and `node2`. The `message` and `args` are processed as in the
    //! CanteraError class.
    template <typename... Args>
    InputFileError(const string& procedure, const AnyBase& node1,
                   const AnyBase& node2, const string& message,
                   const Args&... args)
        : CanteraError(
            procedure,
            formatError2(
                (sizeof...(args) == 0) ? message
                                       : fmt::format(fmt::runtime(message), args...),
                node1.m_line, node1.m_column, node1.m_metadata,
                node2.m_line, node2.m_column, node2.m_metadata))
        {
        }
 
    string getClass() const override {
        return "InputFileError";
    }
protected:
    static string formatError(const string& message, int line, int column,
                              const shared_ptr<AnyMap>& metadata);
    static string formatError2(const string& message,
        int line1, int column1, const shared_ptr<AnyMap>& metadata1,
        int line2, int column2, const shared_ptr<AnyMap>& metadata2);
};
 
//! A deprecation warning for syntax in an input file
void warn_deprecated(const string& source, const AnyBase& node,
                     const string& message);
 
}
 
#include "cantera/base/AnyMap.inl.h"
 
#endif