Add the 'default' example of the QML reference examples

Task-number: PYSIDE-841
Change-Id: I465f9e92b5fca2b6e7e261d1976082e834af528b
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
(cherry picked from commit c9ba44deb48a064eec9229b5426187611c7d592a)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

6 files changed, 330 insertions, 0 deletions

diff --git a/examples/declarative/referenceexamples/default/birthdayparty.py b/examples/declarative/referenceexamples/default/birthdayparty.py
new file mode 100644
index 000000000..3f3fe0894
--- /dev/null
+++ b/examples/declarative/referenceexamples/default/birthdayparty.py
@@ -0,0 +1,79 @@
+#############################################################################
+##
+## 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, ClassInfo, 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.default.people"
+QML_IMPORT_MAJOR_VERSION = 1
+
+
+@QmlElement
+@ClassInfo(DefaultProperty="guests")
+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/default/default.pyproject b/examples/declarative/referenceexamples/default/default.pyproject
new file mode 100644
index 000000000..3c01c40c2
--- /dev/null
+++ b/examples/declarative/referenceexamples/default/default.pyproject
@@ -0,0 +1,3 @@
+{
+    "files": ["main.py", "birthdayparty.py", "person.py", "example.qml"]
+}
diff --git a/examples/declarative/referenceexamples/default/doc/default.rst b/examples/declarative/referenceexamples/default/doc/default.rst
new file mode 100644
index 000000000..1b28519a7
--- /dev/null
+++ b/examples/declarative/referenceexamples/default/doc/default.rst
@@ -0,0 +1,30 @@
+.. _qml-default-property-example:
+
+Extending QML - Default Property Example
+========================================
+
+This example builds on the :ref:`qml-adding-types-example`,
+the :ref:`qml-object-and-list-property-types-example` and
+the :ref:`qml-inheritance-and-coercion-example`.
+
+The Default Property Example is a minor modification of the
+:ref:`qml-inheritance-and-coercion-example` that simplifies the
+specification of a BirthdayParty through the use of a default property.
+
+Declaring the BirthdayParty Class
+---------------------------------
+
+The only difference between this example and the last, is the addition of a
+``DefaultProperty`` class info annotation.
+
+The default property specifies the property to assign to whenever an explicit
+property is not specified, in the case of the BirthdayParty type the guest
+property.  It is purely a syntactic simplification, the behavior is identical
+to specifying the property by name, but it can add a more natural feel in many
+situations.  The default property must be either an object or list property.
+
+Running the Example
+-------------------
+
+The main.py file in the example includes a simple shell application that
+loads and runs the QML snippet shown below.
diff --git a/examples/declarative/referenceexamples/default/example.qml b/examples/declarative/referenceexamples/default/example.qml
new file mode 100644
index 000000000..763c9727c
--- /dev/null
+++ b/examples/declarative/referenceexamples/default/example.qml
@@ -0,0 +1,62 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt for Python 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.default.people
+
+BirthdayParty {
+    host: Boy {
+        name: "Bob Jones"
+        shoe_size: 12
+    }
+
+    Boy { name: "Leo Hodges" }
+    Boy { name: "Jack Smith" }
+    Girl { name: "Anne Brown" }
+}
diff --git a/examples/declarative/referenceexamples/default/main.py b/examples/declarative/referenceexamples/default/main.py
new file mode 100644
index 000000000..a1c4ff91a
--- /dev/null
+++ b/examples/declarative/referenceexamples/default/main.py
@@ -0,0 +1,73 @@
+#############################################################################
+##
+## 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/default 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 Boy, Girl
+from birthdayparty import BirthdayParty
+
+
+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 not party:
+    print(component.errors())
+    del engine
+    sys.exit(-1)
+host = party.host
+print(f"{host.name} is having a birthday!")
+if isinstance(host, Boy):
+    print("He is inviting:")
+else:
+    print("She is inviting:")
+for g in range(party.guestCount()):
+    name = party.guest(g).name
+    print(f"    {name}")
+del engine
+sys.exit(0)
diff --git a/examples/declarative/referenceexamples/default/person.py b/examples/declarative/referenceexamples/default/person.py
new file mode 100644
index 000000000..c66b16690
--- /dev/null
+++ b/examples/declarative/referenceexamples/default/person.py
@@ -0,0 +1,83 @@
+#############################################################################
+##
+## 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 QmlAnonymous, QmlElement
+
+# To be used on the @QmlElement decorator
+# (QML_IMPORT_MINOR_VERSION is optional)
+QML_IMPORT_NAME = "examples.default.people"
+QML_IMPORT_MAJOR_VERSION = 1
+
+
+@QmlAnonymous
+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
+
+
+@QmlElement
+class Boy(Person):
+    def __init__(self, parent=None):
+        super().__init__(parent)
+
+
+@QmlElement
+class Girl(Person):
+    def __init__(self, parent=None):
+        super().__init__(parent)