// Copyright (C) 2025 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
// Qt-Security score:insignificant reason:default

#include <QtCore/qrangemodeladapter.h>

/*!
    \class QRangeModelAdapter
    \inmodule QtCore
    \since 6.11
    \preliminary
    \ingroup model-view
    \brief QRangeModelAdapter provides QAbstractItemModel-compliant access to any C++ range.
    \compares equality
    \compareswith equality Range
    \endcompareswith

    QRangeModelAdapter provides a type-safe and structure-aware C++ API around
    a C++ range and a QRangeModel. Modifications made to the C++ range using
    the adapter will inform clients of the QRangeModel about the changes. This
    makes sure that item views are updated, caches are cleaned, and persistent
    item indexes are invalidated and adapted correctly.

    \section1 Construction and model ownership

    QRangeModelAdapter has to be constructed from a C++ range. As with
    QRangeModel, the range can be provided by lvalue or rvalue reference, as a
    reference wrapper, and as a raw or smart pointer.

    \snippet qrangemodeladapter/main.cpp construct

    Constructing the adapter from a range implicitly constructs a QRangeModel
    instance from that same range. Use model() to get it, and pass it to Qt
    Widgets or Qt Quick item views as usual.

    \snippet qrangemodeladapter/main.cpp use-model

    The adapter owns the model. QRangeModelAdapter is a value type, so it can be
    copied and moved. All copies share the same QRangeModel, which will be
    destroyed when the last copy of the adapter is destroyed.

    If the adapter was created from an lvalue or rvalue reference, then the
    adapter and model will operate on a copy of the original range object.
    Otherwise, modifications made through the adapter or model will be written
    to the original range object. To get the updated range, use the range()
    function explicitly, or use the implicit conversion of the adapter to a
    the range.

    \snippet qrangemodeladapter/main.cpp get-range

    To replace the entire range data with data from another (compatible) range,
    use the setRange() function or the assignment operator.

    \snippet qrangemodeladapter/main.cpp set-range

    \section1 Accessing item data

    The QRangeModelAdapter API provides type-safe read and write access to the
    range that the model operates on. The adapter API is based on the typical
    API for C++ containers and ranges, including iterators. To access
    individual rows and items, use at(), the corresponding subscript
    \c{operator[]}, or data(). Which overloads of those functions are available
    depends on the range for which the adapter was constructed.

    \section2 Reading item data as a QVariant

    The data() function always returns a QVariant with the value stored at the
    specified position and role. In a list, an item can be accessed by a single
    integer value specifying the row:

    \snippet qrangemodeladapter/main.cpp list-data

    If the range is a table, then items are specified by row and column:

    \snippet qrangemodeladapter/main.cpp table-data

    If the range is a tree, then items are located using a path of rows, and a
    single column value:

    \snippet qrangemodeladapter/main.cpp tree-data

    Using a single integer as the row provides access to the toplevel tree
    items.

    \snippet qrangemodeladapter/main.cpp multirole-data

    If no role is specified, then the QVariant will hold the entire item at the
    position. Use the \l{QVariant::fromValue()} template function to retrieve a
    copy of the item.

    \section2 Reading and writing using at()

    That the data() function returns a QVariant makes it flexible, but removes
    type safety. For ranges where all items are of the same type, the at()
    function provides a type-safe alternative that is more compatible with
    regular C++ containers. As with data(), at() overloads exist to access an
    item at a row for lists, at a row/column pair for table, and a path/column
    pair for trees. However, at() always returns the whole item at the
    specified position; it's not possible to read an individual role values for
    an item.

    As expected from a C++ container API, the const overloads of at() (and the
    corresponding subscript \c{operator[]}) provide immutable access to the
    value, while the mutable overloads return a reference object that a new
    value can be assigned to. Note that a QRangeModelAdapter operating on a
    const range behaves in that respect like a const QRangeModelAdapter. The
    mutable overloads are removed from the overload set, so the compiler will
    always select the const version. Trying to call a function that modifies a
    range will result in a compiler error, even if the adapter itself is
    mutable:

    \snippet qrangemodeladapter/main.cpp read-only

    The returned reference objects are wrappers that convert implicitly to the
    underlying type, have a \c{get()} function to explicitly access the
    underlying value, and an \c{operator->()} that provides direct access to
    const member functions. However, to prevent accidental data changes that
    would bypass the QAbstractItemModel notification protocol, those reference
    objects prevent direct modifications of the items.

    \note Accessing the reference object always makes a call to the model to get
    a copy of the value. This can be expensive; for performance critical access
    to data, store a copy.

    \section3 Item access

    If the range is represented as a list, then only the overloads taking a row
    are available.

    \snippet qrangemodeladapter/main.cpp list-access

    The const overload returns the item at that row, while the mutable overload
    returns a wrapper that implicitly converts to and from the value type of the
    list.

    \snippet qrangemodeladapter/main.cpp list-access-multirole

    Assign a value to the wrapper to modify the data in the list. The model will
    emit \l{QAbstractItemModel::}{dataChanged()} for all roles.

    When using the mutable overloads, you can also access the item type's const
    members using the overloaded arrow operator.

    \snippet qrangemodeladapter/main.cpp list-access-multirole-member-access

    It is not possible to access non-const members of the item. Such
    modifications would bypass the adapter, which couldn't notify the model
    about the changes. To modify the value stored in the model, make a copy,
    modify the properties of the copy, and then write that copy back.

    \snippet qrangemodeladapter/main.cpp list-access-multirole-write-back

    This will make the model emit \l{QAbstractItemModel::}{dataChanged()} for
    this item, and for all roles.

    If the range is represented as a table, then you can access an individual
    item by row and columns, using the \l{at(int, int)}{at(row, column)}
    overload. For trees, that overload gives access to top-level items, while
    the \l{at(QSpan<const int>, int)}{at(path, column)} overload provides
    access to items nested within the tree.

    Accessing an individual item in a table or tree is equivalent to accessing
    an item in a list.

    \snippet qrangemodeladapter/main.cpp table-item-access

    If the range doesn't store all columns using the same data type, then
    \c{at(row,column)} returns a (a reference wrapper with a) QVariant holding
    the item.

    \snippet qrangemodeladapter/main.cpp table-mixed-type-access

    \section2 Accessing rows in tables and trees

    For tables and trees, the overloads of at() and subscript \c{operator[]}
    without the column parameter provide access to the entire row. The value
    returned by the const overloads will be a reference type that gives access
    to the row data. If that row holds pointers, then that reference type will
    be a view of the row, giving access to pointers to const items.

    \section3 Table row access

    The \l{at(int)} overload is still available, but it returns the entire table
    wor. This makes it possible to work with all the values in the row at once.

    \snippet qrangemodeladapter/main.cpp table-row-const-access

    As with items, the const overload provides direct access to the row type,
    while the mutable overload returns a wrapper that acts as a reference to the
    row. The wrapper provides access to const member functions using the
    overloaded arrow operator. To modify the values, write a modified row type
    back.

    \snippet qrangemodeladapter/main.cpp table-row-access

    When assigning a new value to the row, then the model emits the
    \l{QAbstractItemModel::}{dataChanged()} signal for all items in the row,
    and for all roles.

    \note When using a row type with runtime sizes, such as a \c{std::vector} or
    a QList, make sure that the new row has the correct size.

    \section3 Tree row access

    Rows in trees are specified by a sequence of integers, one entry for each
    level in the tree. Note that in the following snippets, the Tree is a range
    holding raw row pointers, and that the adapter is created with an rvalue
    reference of that range. This gives the QRangeModel ownership over the row
    data.

    \snippet qrangemodeladapter/main.cpp tree-row-access

    The overload of \l{at(int)}{at()} taking a single row value provides
    access to the top-level rows, or items in the top-level rows.

    \snippet qrangemodeladapter/main.cpp tree-item-access

    The basic pattern for accessing rows and items in a tree is identical to
    accessing rows and items in a table. However, the adapter will make sure
    that the tree structure is maintained when modifying entire rows.

    \snippet qrangemodeladapter/main.cpp tree-row-write

    In this example, a new row object is created, and assigned to the first
    child of the first top-level item.

    \section1 Iterator API

    Use begin() and end() to get iterators over the rows of the model, or use
    ranged-for. If the range is a list of items, dereferencing the iterator
    will give access to item data.

    \snippet qrangemodeladapter/main.cpp ranged-for-const-list

    As with the const and mutable overloads of at(), a mutable iterator will
    dereference to a wrapper.

    \snippet qrangemodeladapter/main.cpp ranged-for-mutable-list

    Use the overloaded arrow operator to access const members of the item type,
    and assign to the wrapper to replace the value.

    It the range is a table or tree, then iterating over the model will give
    access to the rows.

    \snippet qrangemodeladapter/main.cpp ranged-for-const-table

    Both the const and the mutable iterator will dereference to a wrapper type
    for the row. This make sure that we can consistently iterate over each
    column, even if the underlying row type is not a range (e.g. it might be a
    tuple or gadget).

    \snippet qrangemodeladapter/main.cpp ranged-for-const-table-items

    When iterating over a mutable table we can overwrite the entire row.

    \snippet qrangemodeladapter/main.cpp ranged-for-mutable-table

    The model emits the \l{QAbstractItemModel::}{dataChanged()} signal for
    all items in all row, and for all roles.

    \snippet qrangemodeladapter/main.cpp ranged-for-mutable-table-items

    Iterating over the mutable rows allows us to modify individual items.

    When iterating over a tree, the row wrapper has two additional member
    functions, hasChildren() and children(), that allow us to traverse the
    entire tree using iterators.

    \snippet qrangemodeladapter/main.cpp ranged-for-tree

    The object returned by children() is a QRangeModelAdapter operating on
    the same model as the callee, but all operations will use the source row
    index as the parent index.

    \sa QRangeModel
*/

/*!
    \typedef QRangeModelAdapter::range_type
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> QRangeModelAdapter<Range, Protocol, Model>::QRangeModelAdapter(Range &&range, Protocol &&protocol)
    \fn template <typename Range, typename Protocol, typename Model> QRangeModelAdapter<Range, Protocol, Model>::QRangeModelAdapter(Range &&range)

    Constructs a QRangeModelAdapter that operates on \a range. For tree ranges,
    the optional \a protocol will be used for tree traversal.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> bool QRangeModelAdapter<Range, Protocol, Model>::operator==(const QRangeModelAdapter &lhs, const QRangeModelAdapter &rhs)

    \return whether \a lhs is equal to \a rhs. Two adapters are equal if they
    both hold the same \l{model()}{model} instance.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> bool QRangeModelAdapter<Range, Protocol, Model>::operator!=(const QRangeModelAdapter &lhs, const QRangeModelAdapter &rhs)

    \return whether \a lhs is not equal to \a rhs. Two adapters are equal if
    they both hold the same \l{model()}{model} instance.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> Model *QRangeModelAdapter<Range, Protocol, Model>::model() const

    \return the QRangeModel instance created by this adapter.

    \sa range(), at()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> const QRangeModelAdapter<Range, Protocol, Model>::range_type &QRangeModelAdapter<Range, Protocol, Model>::range() const
    \fn template <typename Range, typename Protocol, typename Model> QRangeModelAdapter<Range, Protocol, Model>::operator const QRangeModelAdapter<Range, Protocol, Model>::range_type &() const

    \return a const reference to the range that the model adapter operates on.

    \sa setRange(), at(), model()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename NewRange, QRangeModelAdapter<Range, Protocol, Model>::if_assignable_range<NewRange>> void QRangeModelAdapter<Range, Protocol, Model>::setRange(NewRange &&newRange)
    \fn template <typename Range, typename Protocol, typename Model> template <typename NewRange, QRangeModelAdapter<Range, Protocol, Model>::if_assignable_range<NewRange>, QRangeModelAdapter<Range, Protocol, Model>::unless_adapter<NewRange>> QRangeModelAdapter &QRangeModelAdapter<Range, Protocol, Model>::operator=(NewRange &&newRange)

    Replaces the contents of the model with the rows in \a newRange, possibly
    using move semantics.

    This function makes the model() emit the \l{QAbstractItemModel::}{modelAboutToBeReset()}
    and \l{QAbstractItemModel::}{modelReset()} signals.

    \constraints \c Range is mutable, and \a newRange is of a type that can be
                 assigned to \c Range, but not a QRangeModelAdapter.

    \sa range(), at(), model(), assign()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename Row, QRangeModelAdapter<Range, Protocol, Model>::if_assignable_range<std::initializer_list<Row>>> void QRangeModelAdapter<Range, Protocol, Model>::setRange(std::initializer_list<Row> newRange)
    \fn template <typename Range, typename Protocol, typename Model> template <typename Row, QRangeModelAdapter<Range, Protocol, Model>::if_assignable_range<std::initializer_list<Row>>> QRangeModelAdapter &QRangeModelAdapter<Range, Protocol, Model>::assign(std::initializer_list<Row> newRange)
    \fn template <typename Range, typename Protocol, typename Model> template <typename Row, QRangeModelAdapter<Range, Protocol, Model>::if_assignable_range<std::initializer_list<Row>>> QRangeModelAdapter &QRangeModelAdapter<Range, Protocol, Model>::operator=(std::initializer_list<Row> newRange)

    Replaces the contents of the model with the rows in \a newRange.

    \constraints \c Range is mutable, and \a newRange can be assigned to \c Range.

    \sa range(), at, model()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename InputIterator, typename Sentinel, typename I = Impl, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> void QRangeModelAdapter<Range, Protocol, Model>::setRange(InputIterator first, Sentinel last)
    \fn template <typename Range, typename Protocol, typename Model> template <typename InputIterator, typename Sentinel, typename I = Impl, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> void QRangeModelAdapter<Range, Protocol, Model>::assign(InputIterator first, Sentinel last)

    Replaces the contents of the models with the rows in the range [\a first, \a last).

    \sa range(), at, model()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_list<I>> QModelIndex QRangeModelAdapter<Range, Protocol, Model>::index(int row) const
    \overload

    Returns the QModelIndex for \a row.

    \constraints \c Range is a one-dimensional list.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>> QModelIndex QRangeModelAdapter<Range, Protocol, Model>::index(int row, int column) const
    \overload

    Returns the QModelIndex for the item at \a row, \a column.

    \constraints \c Range is a table or tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> QModelIndex QRangeModelAdapter<Range, Protocol, Model>::index(QSpan<const int> path, int column) const
    \overload

    Returns the QModelIndex for the item at \a column for the row in the tree
    specified by \a path.

    \constraints \c Range is a tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> int QRangeModelAdapter<Range, Protocol, Model>::columnCount() const

    \return the number of columns. This will be one if the \c Range represents a
    list, otherwise this returns be the number of elements in each row.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> int QRangeModelAdapter<Range, Protocol, Model>::rowCount() const
    \overload

    \return the number of rows. If the \c Range represents a list or table, then
    this is the number of rows. For trees, this is the number of top-level rows.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> int QRangeModelAdapter<Range, Protocol, Model>::rowCount(int row) const
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> int QRangeModelAdapter<Range, Protocol, Model>::rowCount(QSpan<const int> row) const
    \overload

    \return the number of rows under \a row.
    \constraints \c Range is a tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> int QRangeModelAdapter<Range, Protocol, Model>::hasChildren(int row) const
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> int QRangeModelAdapter<Range, Protocol, Model>::hasChildren(QSpan<const int> row) const
    \overload

    \return whether there are any rows under \a row.
    \constraints \c Range is a tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_list<I>> QVariant QRangeModelAdapter<Range, Protocol, Model>::data(int row) const
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_list<I>> QVariant QRangeModelAdapter<Range, Protocol, Model>::data(int row, int role) const

    \return a QVariant holding the data stored under the given \a role for the
    item at \a row, or an invalid QVariant if there is no item. If \a role is
    not specified, then returns a QVariant holding the complete item.

    \constraints \c Range is a list.

    \sa setData(), at()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_list<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> bool QRangeModelAdapter<Range, Protocol, Model>::setData(int row, const QVariant &value, int role)

    Sets the \a role data for the item at \a row to \a value.

    Returns \c{true} if successful; otherwise returns \c{false}.

    \constraints \c Range is a mutable list.

    \sa data(), at()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>> QVariant QRangeModelAdapter<Range, Protocol, Model>::data(int row, int column) const
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>> QVariant QRangeModelAdapter<Range, Protocol, Model>::data(int row, int column, int role) const

    \return a QVariant holding the data stored under the given \a role for the
    item referred to by a \a row and \a column, or an invalid QVariant if there
    is no data stored for that position or role. If \a role is not specified,
    then returns a QVariant holding the complete item.

    \constraints \c Range is a table or tree.

    \sa setData(), at()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> bool QRangeModelAdapter<Range, Protocol, Model>::setData(int row, int column, const QVariant &value, int role)

    Sets the \a role data for the item referred to by \a row and \a column to
    \a value.

    Returns \c{true} if successful; otherwise returns \c{false}.

    \constraints \c Range is mutable, and not a list.

    \sa data(), at()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> QVariant QRangeModelAdapter<Range, Protocol, Model>::data(QSpan<const int> path, int column) const
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> QVariant QRangeModelAdapter<Range, Protocol, Model>::data(QSpan<const int> path, int column, int role) const

    \return a QVariant holding the data stored under the given \a role for the
    item referred to by \a path and \a column, or an invalid QVariant if there
    is no data stored for that position or role. If \a role is not specified,
    then returns a QVariant holding the complete item.

    \constraints \c Range is a tree.

    \sa setData(), at()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> bool QRangeModelAdapter<Range, Protocol, Model>::setData(QSpan<const int> path, int column, const QVariant &value, int role)

    Sets the \a role data for the item referred to by \a path and \a column to
    \a value.

    Returns \c{true} if successful; otherwise returns \c{false}.

    \constraints \c Range is a mutable tree.

    \sa data(), at()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_list<I>> auto QRangeModelAdapter<Range, Protocol, Model>::at(int row) const
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_list<I>> auto QRangeModelAdapter<Range, Protocol, Model>::operator[](int row) const

    \return the value at \a row as the type stored in \c Range.

    \constraints \c Range is a list.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_list<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::at(int row)
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_list<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::operator[](int row)

    \return the value at \a row wrapped into a mutable reference to the type
    stored in \c Range.

//! [data-ref]
    \note Modifications to the range will invalidate that reference. To modify
    the reference, assign a new value to it. Unless the value stored in the
    \c Range is a pointer, it is not possible to access individual members of
    the stored value.
//! [data-ref]

    \constraints \c Range is a mutable list.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>> decltype(auto) QRangeModelAdapter<Range, Protocol, Model>::at(int row) const
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>> decltype(auto) QRangeModelAdapter<Range, Protocol, Model>::operator[](int row) const

    \return a constant reference to the row at \a row, as stored in \c Range.

    \constraints \c Range is a table or tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_table<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::at(int row)
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_table<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::operator[](int row)

    \return a mutable reference to the row at \a row, as stored in \c Range.

    \constraints \c Range is a mutable table, but not a tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::at(int row)
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::operator[](int row)

    \return a mutable wrapper holding a reference to the tree row specified by \a row.

//! [treerow-ref]
    To modify the tree row, assign a new value to it. Assigning a new tree row
    will set the parent the new tree row to be the parent of the old tree row.
    However, neither the old nor the new tree row must have any child rows. To
    access the tree row, dereferencing the wrapper using \c{operator*()}, or use
    \c{operator->()} to access tree row members.

    \note Modifications to the range will invalidate the wrapper.
//! [treerow-ref]

    \constraints \c Range is a tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>> auto QRangeModelAdapter<Range, Protocol, Model>::at(int row, int column) const
\omit
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>> auto QRangeModelAdapter<Range, Protocol, Model>::operator[](int row, int column) const
\endomit

    \return a copy of the value stored as the item specified by \a row and
    \a column. If the item is a multi-role item, then this returns a copy of
    the entire item. If the rows in the \c Range store different types at
    different columns, then the return type will be a QVariant.

    \constraints \c Range is a table or tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::at(int row, int column)
\omit
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::unless_list<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::operator[](int row, int column)
\endomit

    \return a mutable reference to the value stored as the item specified by
    \a row and \a column. If the item is a multi-role item, then this will be
    a reference to the entire item.

    \include qrangemodeladapter.qdoc data-ref

    \constraints \c Range is a mutable table.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> decltype(auto) QRangeModelAdapter<Range, Protocol, Model>::at(QSpan<const int> path) const
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> decltype(auto) QRangeModelAdapter<Range, Protocol, Model>::operator[](QSpan<const int> path) const

    \return a constant reference to the row specified by \a path, as stored in
    \c Range.

    \constraints \c Range is a tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::at(QSpan<const int> path)
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::operator[](QSpan<const int> path)

    \return a mutable wrapper holding a reference to the tree row specified by \a path.

    \include qrangemodeladapter.qdoc treerow-ref

    \constraints \c Range is a tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> auto QRangeModelAdapter<Range, Protocol, Model>::at(QSpan<const int> path, int column) const
\omit
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> auto QRangeModelAdapter<Range, Protocol, Model>::operator[](QSpan<const int> path, int column) const
\endomit

    \return a copy of the value stored as the item specified by \a path and
    \a column. If the item is a multi-role item, then this returns a copy of
    the entire item. If the rows in the \c Range store different types at
    different columns, then the return type will be a QVariant.

    \constraints \c Range is a tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::at(QSpan<const int> path, int column)
\omit
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>, QRangeModelAdapter<Range, Protocol, Model>::if_writable<I>> auto QRangeModelAdapter<Range, Protocol, Model>::operator[](QSpan<const int> path, int column)
\endomit

    \return a mutable reference to the value stored as the item specified by
    \a path and \a column. If the item is a multi-role item, then this will be
    a reference to the entire item. If the rows in the \c Range store different
    types at different columns, then the return type will be a QVariant.

    \include qrangemodeladapter.qdoc data-ref

    \constraints \c Range is a mutable tree.
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canInsertRows<I>> bool QRangeModelAdapter<Range, Protocol, Model>::insertRow(int before)
    \overload

    Inserts a single empty row before the row at \a before, and returns whether
    the insertion was successful.
//! [insert-row-appends]
    If \a before is the same value as rowCount(), then the new row will be appended.
//! [insert-row-appends]

    \constraints \c Range supports insertion of elements.

    \sa insertRows(), removeRow(), insertColumn()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canInsertRows<I>, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> bool QRangeModelAdapter<Range, Protocol, Model>::insertRow(QSpan<const int> before)
    \overload

    Inserts a single empty row before the row at the path specified by \a before,
    and returns whether the insertion was successful.
    \include qrangemodeladapter.qdoc insert-row-appends

    \constraints \c Range is a tree that supports insertion of elements.

    \sa insertRows(), removeRow(), insertColumn()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename D, typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canInsertRows<I>, QRangeModelAdapter<Range, Protocol, Model>::if_compatible_row<D>> bool QRangeModelAdapter<Range, Protocol, Model>::insertRow(int before, D &&data)
    \overload

    Inserts a single row constructed from \a data before the row at \a before,
    and returns whether the insertion was successful.
    \include qrangemodeladapter.qdoc insert-row-appends

    \constraints \c Range supports insertion of elements, and if
                 a row can be constructed from \a data.

    \sa insertRows(), removeRow(), insertColumn()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename D, typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canInsertRows<I>, QRangeModelAdapter<Range, Protocol, Model>::if_compatible_row<D>, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> bool QRangeModelAdapter<Range, Protocol, Model>::insertRow(QSpan<const int> before, D &&data)
    \overload

    Inserts a single row constructed from \a data before the row at \a before,
    and returns whether the insertion was successful.
    \include qrangemodeladapter.qdoc insert-row-appends

    \constraints \c Range is a tree that supports insertion of elements, and if
                 a row can be constructed from \a data.

    \sa insertRows(), removeRow(), insertColumn()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename C, typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canInsertRows<I>, QRangeModelAdapter<Range, Protocol, Model>::if_compatible_row_range<C>> bool QRangeModelAdapter<Range, Protocol, Model>::insertRows(int before, C &&data)
    \overload

    Inserts rows constructed from the elements in \a data before the row at
    \a before, and returns whether the insertion was successful.
    \include qrangemodeladapter.qdoc insert-row-appends

    \constraints \c Range supports insertion of elemnets, and if
                 rows can be constructed from the elements in \a data.

    \sa insertRow(), removeRows(), insertColumns()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename C, typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canInsertRows<I>, QRangeModelAdapter<Range, Protocol, Model>::if_compatible_row_range<C>, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> bool QRangeModelAdapter<Range, Protocol, Model>::insertRows(QSpan<const int> before, C &&data)
    \overload

    Inserts rows constructed from the elements in \a data before the row at
    \a before, and returns whether the insertion was successful.
    \include qrangemodeladapter.qdoc insert-row-appends

    \constraints \c Range is a tree that supports insertion of elements, and if
                 rows can be constructed from the elements in \a data.

    \sa insertRow(), removeRows(), insertColumns()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canRemoveRows<I>> bool QRangeModelAdapter<Range, Protocol, Model>::removeRow(int row)
    \overload

    Removes the given \a row and returns whether the removal was successful.

    \constraints \c Range supports the removal of elements.

    \sa removeRows(), removeColumn(), insertRow()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canRemoveRows<I>, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> bool QRangeModelAdapter<Range, Protocol, Model>::removeRow(QSpan<const int> path)
    \overload

    Removes the row at the given \a path, including all children of that row,
    and returns whether the removal was successful.

    \constraints \c Range is a tree that supports the removal of elements.

    \sa removeRows(), removeColumn(), insertRow()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canRemoveRows<I>> bool QRangeModelAdapter<Range, Protocol, Model>::removeRows(int row, int count)
    \overload

    Removes \a count rows starting at \a row, and returns whether the removal
    was successful.

    \constraints \c Range supports the removal of elements.

    \sa removeRow(), removeColumns(), insertRows()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canRemoveRows<I>, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> bool QRangeModelAdapter<Range, Protocol, Model>::removeRows(QSpan<const int> path, int count)
    \overload

    Removes \a count rows starting at the row specified by \a path, and returns
    whether the removal was successful.

    \constraints \c Range is a tree that supports the removal of elements.

    \sa removeRow(), removeColumns(), insertRows()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename F, QRangeModelAdapter<Range, Protocol, Model>::if_canMoveItems<F>> bool QRangeModelAdapter<Range, Protocol, Model>::moveRow(int source, int destination)
    \overload

    Moves the row at \a source to the position at \a destination, and returns
    whether the row was successfully moved.

    \constraints \c Range supports moving of elements.

    \sa insertRow(), removeRow(), moveColumn()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, typename F, QRangeModelAdapter<Range, Protocol, Model>::if_canMoveItems<F>, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> bool QRangeModelAdapter<Range, Protocol, Model>::moveRow(QSpan<const int> source, QSpan<const int> destination)
    \overload

    Moves the tree branch at \a source to the position at \a destination, and
    returns whether the branch was successfully moved.

    \constraints \c Range is a tree that supports moving of elements.

    \sa insertRow(), removeRow(), moveColumn()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename F, QRangeModelAdapter<Range, Protocol, Model>::if_canMoveItems<F>> bool QRangeModelAdapter<Range, Protocol, Model>::moveRows(int source, int count, int destination)
    \overload

    Moves \a count rows starting at \a source to the position at \a destination,
    and returns whether the rows were successfully moved.

    \constraints \c Range supports moving of elements.

    \sa insertRows(), removeRows(), moveColumns()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, typename F, QRangeModelAdapter<Range, Protocol, Model>::if_canMoveItems<F>, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> bool QRangeModelAdapter<Range, Protocol, Model>::moveRows(QSpan<const int> source, int count, QSpan<const int> destination)
    \overload

    Moves \a count tree branches starting at \a source to the position at
    \a destination, and returns whether the rows were successfully moved.

    \constraints \c Range is a tree that supports moving of elements.

    \sa insertRows(), removeRows(), moveColumns()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canInsertColumns<I>> bool QRangeModelAdapter<Range, Protocol, Model>::insertColumn(int before)
    \overload

    Inserts a single empty column before the column specified by \a before into
    all rows, and returns whether the insertion was successful.
//! [insert-column-appends]
    If \a before is the same value as columnCount(), then the column will be
    appended to each row.
//! [insert-column-appends]

    \constraints \c Range has rows that support insertion of elements.

    \sa removeColumn(), insertColumns(), insertRow()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename D, typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canInsertColumns<I>, QRangeModelAdapter<Range, Protocol, Model>::if_compatible_column_data<D>> bool QRangeModelAdapter<Range, Protocol, Model>::insertColumn(int before, D &&data)
    \overload

    Inserts a single column constructed from \a data before the column specified
    by \a before into all rows, and returns whether the insertion was successful.
//! [insert-column-appends]
    If \a before is the same value as columnCount(), then the column will be
    appended to each row.
//! [insert-column-appends]

    If \a data is a single value, then the new entry in all rows will be constructed
    from that single value.

    If \a data is a container, then the elements in that container will be used
    sequentially to construct the column for each subsequent row. If there are
    fewer elements in \a data than there are rows, then function wraps around
    and starts again from the first element.

    \code
    \endcode

    \constraints \c Range has rows that support insertion of elements, and the
                 elements can be constructed from the entries in \a data.

    \sa removeColumn(), insertColumns(), insertRow()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename C, typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canInsertColumns<I>, QRangeModelAdapter<Range, Protocol, Model>::if_compatible_column_range<C>> bool QRangeModelAdapter<Range, Protocol, Model>::insertColumns(int before, C &&data)

    Inserts columns constructed from the elements in \a data before the column
    specified by \a before into all rows, and returns whether the insertion was
    successful.
//! [insert-column-appends]
    If \a before is the same value as columnCount(), then the column will be
    appended to each row.
//! [insert-column-appends]

    If the elements in \a data are values, then the new entries in all rows will
    be constructed from those values.

    If the elements in \a data are containers, then the entries in the outer
    container will be used sequentially to construct the new entries for each
    subsequent row. If there are fewer elements in \a data than there are rows,
    then the function wraps around and starts again from the first element.

    \code
    \endcode

    \constraints \c Range has rows that support insertion of elements, and the
                 elements can be constructed from the entries in \a data.

    \sa removeColumns(), insertColumn(), insertRows()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canRemoveColumns<I>> bool QRangeModelAdapter<Range, Protocol, Model>::removeColumn(int column)

    Removes the given \a column from each row, and returns whether the removal
    was successful.

    \constraints \c Range has rows that support removal of elements.

    \sa insertColumn(), removeColumns(), removeRow()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, QRangeModelAdapter<Range, Protocol, Model>::if_canRemoveColumns<I>> bool QRangeModelAdapter<Range, Protocol, Model>::removeColumns(int column, int count)

    Removes \a count columns starting by the given \a column from each row, and
    returns whether the removal was successful.

    \constraints \c Range has rows that support removal of elements.

    \sa insertColumns(), removeColumn(), removeRow()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename F, QRangeModelAdapter<Range, Protocol, Model>::if_canMoveItems<F>> bool QRangeModelAdapter<Range, Protocol, Model>::moveColumn(int from, int to)

    Moves the column at \a from to the column at \a to, and returns whether the
    column was successfully moved.

    \constraints \c Range has rows that support moving of elements.

    \sa insertColumn(), removeColumn(), moveColumns(), moveRow()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename F, QRangeModelAdapter<Range, Protocol, Model>::if_canMoveItems<F>> bool QRangeModelAdapter<Range, Protocol, Model>::moveColumns(int from, int count, int to)

    Moves \a count columns starting at \a from to the position at \a to, and
    returns whether the columns were successfully moved.

    \constraints \c Range has rows that support moving of elements.

    \sa insertColumns(), removeColumns(), moveColumn(), moveRows()
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, typename F, QRangeModelAdapter<Range, Protocol, Model>::if_canMoveItems<F>, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> bool QRangeModelAdapter<Range, Protocol, Model>::moveColumn(QSpan<const int> source, int to)
    \internal Not possible to create a tree from a row type that can rotate/splice?
*/

/*!
    \fn template <typename Range, typename Protocol, typename Model> template <typename I, typename F, QRangeModelAdapter<Range, Protocol, Model>::if_canMoveItems<F>, QRangeModelAdapter<Range, Protocol, Model>::if_tree<I>> bool QRangeModelAdapter<Range, Protocol, Model>::moveColumns(QSpan<const int> source, int count, int to)
    \internal Not possible to create a tree from a row type that can rotate/splice?
*/