Add the 'properties' example of the QML reference examples

Task-number: PYSIDE-841
Change-Id: I6565bdbbc4ea401c027f6aab41598df48c779799
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
(cherry picked from commit e057d9f4cbfd97e5fc0bdec564f63fabe5b50189)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

7 files changed, 381 insertions, 0 deletions

diff --git a/examples/declarative/referenceexamples/adding/doc/adding.rst b/examples/declarative/referenceexamples/adding/doc/adding.rst
index b060f3c2c..55f6105b7 100644
--- a/examples/declarative/referenceexamples/adding/doc/adding.rst
+++ b/examples/declarative/referenceexamples/adding/doc/adding.rst
@@ -1,3 +1,5 @@
+.. _qml-adding-types-example:
+
 Extending QML - Adding Types Example
 ====================================
 
diff --git a/examples/declarative/referenceexamples/properties/birthdayparty.py b/examples/declarative/referenceexamples/properties/birthdayparty.py
new file mode 100644
index 000000000..9b4a8428d
--- /dev/null
+++ b/examples/declarative/referenceexamples/properties/birthdayparty.py
@@ -0,0 +1,78 @@
+#############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * 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.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## 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."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+from PySide6.QtCore import QObject, Property
+from PySide6.QtQml import QmlElement, ListProperty
+
+from person import Person
+
+
+# To be used on the @QmlElement decorator
+# (QML_IMPORT_MINOR_VERSION is optional)
+QML_IMPORT_NAME = "examples.properties.people"
+QML_IMPORT_MAJOR_VERSION = 1
+
+
+@QmlElement
+class BirthdayParty(QObject):
+
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        self._host = None
+        self._guests = []
+
+    @Property(Person)
+    def host(self):
+        return self._host
+
+    @host.setter
+    def host(self, h):
+        self._host = h
+
+    def guest(self, n):
+        return self._guests[n]
+
+    def guestCount(self):
+        return len(self._guests)
+
+    def appendGuest(self, guest):
+        self._guests.append(guest)
+
+    guests = ListProperty(Person, appendGuest)
diff --git a/examples/declarative/referenceexamples/properties/doc/properties.rst b/examples/declarative/referenceexamples/properties/doc/properties.rst
new file mode 100644
index 000000000..86c0ef96f
--- /dev/null
+++ b/examples/declarative/referenceexamples/properties/doc/properties.rst
@@ -0,0 +1,89 @@
+_qml-object-and-list-property-types-example:
+
+Extending QML - Object and List Property Types Example
+======================================================
+
+Exporting C++ Properties.
+
+This example builds on :ref:`qml-adding-types-example`.
+
+The Object and List Property Types example shows how to add object and list
+properties in QML. This example adds a BirthdayParty type that specifies a
+birthday party, consisting of a celebrant and a list of guests. People are
+specified using the People QML type built in the previous example.
+
+import examples.properties.people
+
+.. code-block:: javascript:
+
+    BirthdayParty {
+        host: Person {
+            name: "Bob Jones"
+            shoe_size: 12
+        }
+        guests: [
+            Person { name: "Leo Hodges" },
+            Person { name: "Jack Smith" },
+            Person { name: "Anne Brown" }
+        ]
+    }
+
+Declare the BirthdayParty
+-------------------------
+
+The BirthdayParty class is declared like this:
+
+.. code-block:: python:
+
+    from person import Person
+
+
+    # To be used on the @QmlElement decorator
+    # (QML_IMPORT_MINOR_VERSION is optional)
+    QML_IMPORT_NAME = "examples.properties.people"
+    QML_IMPORT_MAJOR_VERSION = 1
+
+
+    @QmlElement
+    class BirthdayParty(QObject):
+
+        def __init__(self, parent=None):
+            super().__init__(parent)
+            self._host = None
+            self._guests = []
+
+        @Property(Person)
+        def host(self):
+            return self._host
+
+        @host.setter
+        def host(self, h):
+            self._host = h
+
+        def guest(self, n):
+            return self._guests[n]
+
+        def guestCount(self):
+            return len(self._guests)
+
+        def appendGuest(self, guest):
+            self._guests.append(guest)
+
+        guests = ListProperty(Person, appendGuest)
+
+The class contains a member to store the celebrant object, and also a
+list member storing the Person instances.
+
+In QML, the type of a list properties - and the guests property is a list of
+people - are all of type ListProperty.  ListProperty is simple value
+type that contains a set of functions.  QML calls these functions
+whenever it needs to read from, write to or otherwise interact with
+the list.  In addition to concrete lists like the people list used in this
+example, the use of QQmlListProperty allows for "virtual lists" and other advanced
+scenarios.
+
+Running the Example
+-------------------
+
+The main.py file in the example includes a simple shell application that
+loads and runs the QML snippet shown at the beginning of this page.
diff --git a/examples/declarative/referenceexamples/properties/example.qml b/examples/declarative/referenceexamples/properties/example.qml
new file mode 100644
index 000000000..7e9f42bbf
--- /dev/null
+++ b/examples/declarative/referenceexamples/properties/example.qml
@@ -0,0 +1,63 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * 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.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import examples.properties.people
+
+BirthdayParty {
+    host: Person {
+        name: "Bob Jones"
+        shoe_size: 12
+    }
+    guests: [
+        Person { name: "Leo Hodges" },
+        Person { name: "Jack Smith" },
+        Person { name: "Anne Brown" }
+    ]
+}
diff --git a/examples/declarative/referenceexamples/properties/main.py b/examples/declarative/referenceexamples/properties/main.py
new file mode 100644
index 000000000..d26747383
--- /dev/null
+++ b/examples/declarative/referenceexamples/properties/main.py
@@ -0,0 +1,71 @@
+#############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * 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.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## 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."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+"""PySide6 port of the qml/examples/qml/referenceexamples/properties example from Qt v6.x"""
+
+from pathlib import Path
+import sys
+
+from PySide6.QtCore import QCoreApplication, QUrl
+from PySide6.QtQml import QQmlComponent, QQmlEngine
+
+from person import Person
+from birthdayparty import BirthdayParty
+
+
+if __name__ == '__main__':
+    app = QCoreApplication(sys.argv)
+
+    qml_file = Path(__file__).parent / "example.qml"
+    url = QUrl.fromLocalFile(qml_file)
+    engine = QQmlEngine()
+    component = QQmlComponent(engine, url)
+
+    party = component.create()
+    if party:
+        print(f"{party.host} is having a birthday!\nThey are inviting:")
+        for g in range(party.guestCount()):
+            name = party.guest(g).name
+            print(f"    {name}")
+    else:
+        print(component.errors())
+
+    del engine
+    sys.exit(0)
diff --git a/examples/declarative/referenceexamples/properties/person.py b/examples/declarative/referenceexamples/properties/person.py
new file mode 100644
index 000000000..e08d9ae90
--- /dev/null
+++ b/examples/declarative/referenceexamples/properties/person.py
@@ -0,0 +1,72 @@
+#############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * 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.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## 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."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+from PySide6.QtCore import QObject, Property
+from PySide6.QtQml import QmlElement
+
+# To be used on the @QmlElement decorator
+# (QML_IMPORT_MINOR_VERSION is optional)
+QML_IMPORT_NAME = "examples.properties.people"
+QML_IMPORT_MAJOR_VERSION = 1
+
+
+@QmlElement
+class Person(QObject):
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        self._name = ''
+        self._shoe_size = 0
+
+    @Property(str)
+    def name(self):
+        return self._name
+
+    @name.setter
+    def name(self, n):
+        self._name = n
+
+    @Property(int)
+    def shoe_size(self):
+        return self._shoe_size
+
+    @shoe_size.setter
+    def shoe_size(self, s):
+        self._shoe_size = s
+
diff --git a/examples/declarative/referenceexamples/properties/properties.pyproject b/examples/declarative/referenceexamples/properties/properties.pyproject
new file mode 100644
index 000000000..0f5958fc3
--- /dev/null
+++ b/examples/declarative/referenceexamples/properties/properties.pyproject
@@ -0,0 +1,6 @@
+{
+    "files": ["example.qml",
+              "main.py",
+              "person.py",
+              "birthdayparty.py"]
+}