Merge pull request #8 from davidhozic/feat/abstractclasses

Polymorphism, abstraction

Author: davidhozic

docs/source/changelog.rst

@@ -24,6 +24,13 @@ Glossary
 Releases
 ---------------------
 
+v1.1.0
+================
+- :ref:`Abstract classes` (those that directly inherit :class:`abc.ABC`) are no longer
+  definable through TkClassWizard.
+- :ref:`Polymorphism` support
+
+
 v1.0.1
 =================
 - Fixed a bug where the window didn't close and couldn't be closed

docs/source/guide/abstractclasses.rst

@@ -0,0 +1,111 @@
+===================
+Abstract classes
+===================
+
+Abstract classes in Object Oriented Programming (OOP) are classes that cannot be instantiated.
+In Python, abstract classes can be by inheriting the :class:`abc.ABC` class. Abstract classes also need to have
+abstract methods, otherwise Python will not treat the class as abstract. Trying to create an instance (object)
+from an abstract class results in a TypeError exception.
+
+.. code-block:: python
+
+    from abc import ABC, abstractmethod
+
+    class MyAbstractClass(ABC):
+        @abstractmethod
+        def some_method(self):
+            pass
+
+    class MyClass(MyAbstractClass):
+        def some_method(self):
+            return 5 * 5
+
+    # OK
+    my_instance = MyClass()
+
+    # TypeError: Can't instantiate abstract class MyClass with abstract method some_method
+    my_abstract_instance = MyAbstractClass()
+
+
+Let's modify our example from :ref:`Polymorphism`.
+
+.. code-block:: python
+    :linenos:
+    :emphasize-lines: 1, 8, 12
+
+    from abc import ABC, abstractmethod
+
+    import tkinter as tk
+    import tkinter.ttk as ttk
+    import tkclasswiz as wiz
+
+    # An abstract class
+    class Wheel(ABC):
+        def __init__(self, diameter: float):
+            self.diameter = diameter
+
+        @abstractmethod
+        def get_info(self) -> str:
+            pass
+
+    class WinterWheel(Wheel):
+        def get_info(self) -> str:
+            return "Wheel for winter."
+
+    class SummerWheel(Wheel):
+        def get_info(self) -> str:
+            return "Wheel for summer."
+
+
+    class Car:
+        def __init__(self, name: str, speed: float, wheels: list[Wheel]):
+            self.name = name
+            self.speed = speed
+            self.wheels = wheels
+
+            if speed > 50_000:
+                raise ValueError("Car can go up to 50 000 km / h")
+
+            if len(wheels) != 4:
+                raise ValueError("The car must have 4 wheels!")
+
+    # Tkinter main window
+    root = tk.Tk("Test")
+
+    # Modified tkinter Combobox that will store actual objects instead of strings
+    combo = wiz.ComboBoxObjects(root)
+    combo.pack(fill=tk.X, padx=5)
+
+    def make_car(old = None):
+        """
+        Function for opening a window either in new definition mode (old = None) or
+        edit mode (old != None)
+        """
+        assert old is None or isinstance(old, wiz.ObjectInfo)
+
+        window = wiz.ObjectEditWindow()  # The object definition window / wizard
+        window.open_object_edit_frame(Car, combo, old_data=old)  # Open the actual frame
+
+    def print_defined():
+        data = combo.get()
+        data = wiz.convert_to_objects(data)  # Convert any abstract ObjectInfo objects into actual Python objects
+        print(f"Object: {data}; Type: {type(data)}",)  # Print the object and it's datatype
+
+
+    # Main GUI structure
+    ttk.Button(text="Define Car", command=make_car).pack()
+    ttk.Button(text="Edit Car", command=lambda: make_car(combo.get())).pack()
+    ttk.Button(text="Print defined", command=print_defined).pack()
+    root.mainloop()
+
+
+We can see that the ``Wheel`` is now an abstract class.
+It is then inherited by ``WinterWheel`` and ``SummerWheel``.
+If we try to define the ``wheels`` parameter of our ``Car`` object, only these two inherited classes
+will be definable. 
+
+.. image:: ./images/new_define_frame_list_abstractclass.png
+    :width: 15cm
+
+We can see that while ``WinterWheel`` and ``SummerWheel`` are definable (due to :ref:`Polymorphism`),
+``Wheel`` is not.

docs/source/guide/images/new_define_frame_list_abstractclass.png

@@ -13,3 +13,5 @@ Index:
     validation
     annotations
     conversion
+    polymorphism
+    abstractclasses

docs/source/guide/images/new_define_frame_list_polymorphism.png

@@ -0,0 +1,90 @@
+
+====================================
+Polymorphism
+====================================
+
+Polymorphism is a term used to describe the phenomenon of something appearing in multiple forms.
+In nature an example would be a dog. A dog can appear in different forms (breeds). It also means
+that multiple dog forms (breeds) are all derived from a common form - dog.
+
+In the Object Oriented Programming (OOP), this means that an object might appear as either
+an instance of a its actual class or an instance of a superclass.
+
+Let's modify our original guide example:
+
+
+.. code-block:: python
+    :linenos:
+    :emphasize-lines: 10,11,13,14,22
+
+    import tkinter as tk
+    import tkinter.ttk as ttk
+    import tkclasswiz as wiz
+
+    # Normal Python classes with annotations (type hints)
+    class Wheel:
+        def __init__(self, diameter: float):
+            self.diameter = diameter
+
+    class WinterWheel(Wheel):
+        pass
+
+    class SummerWheel(Wheel):
+        pass
+        
+
+    class Car:
+        def __init__(
+            self,
+            name: str,
+            speed: float,
+            wheels: list[Wheel]
+        ):
+            self.name = name
+            self.speed = speed
+            self.wheels = wheels
+
+            if speed > 50_000:
+                raise ValueError("Car can go up to 50 000 km / h")
+
+            if len(wheels) != 4:
+                raise ValueError("The car must have 4 wheels!")
+
+    # Tkinter main window
+    root = tk.Tk("Test")
+
+    # Modified tkinter Combobox that will store actual objects instead of strings
+    combo = wiz.ComboBoxObjects(root)
+    combo.pack(fill=tk.X, padx=5)
+
+    def make_car(old = None):
+        """
+        Function for opening a window either in new definition mode (old = None) or
+        edit mode (old != None)
+        """
+        assert old is None or isinstance(old, wiz.ObjectInfo)
+
+        window = wiz.ObjectEditWindow()  # The object definition window / wizard
+        window.open_object_edit_frame(Car, combo, old_data=old)  # Open the actual frame
+
+    def print_defined():
+        data = combo.get()
+        data = wiz.convert_to_objects(data)  # Convert any abstract ObjectInfo objects into actual Python objects
+        print(f"Object: {data}; Type: {type(data)}",)  # Print the object and it's datatype
+
+
+    # Main GUI structure
+    ttk.Button(text="Define Car", command=make_car).pack()
+    ttk.Button(text="Edit Car", command=lambda: make_car(combo.get())).pack()
+    ttk.Button(text="Print defined", command=print_defined).pack()
+    root.mainloop()
+
+
+We can see that two new classes are created - ``WinterWheel`` and ``SummerWheel``.
+We also see that ``Car``'s ``wheels`` parameter is still a list of type ``Wheel``.
+TkClassWizard not only considers the annotated type when constructing a GUI, but also the annotated type's subclasses,
+implementing the concept of polymorphism, thus allowing us definition of
+``Wheel``, ``WinterWheel`` and ``SummerWheel`` classes.
+
+.. image:: ./images/new_define_frame_list_polymorphism.png
+    :width: 15cm

docs/source/guide/index.rst

@@ -3,7 +3,7 @@
 Works with Tkinter / TTKBootstrap.
 """
 
-__version__ = "1.0.1"
+__version__ = "1.1.0"
 
 from .object_frame import *
 from .annotations import *

docs/source/guide/polymorphism.rst

@@ -1,4 +1,5 @@
 from typing import get_args, get_origin, Iterable, Union, Literal, Any, TYPE_CHECKING, TypeVar
+from abc import ABC
 from contextlib import suppress
 
 from ..convert import *
@@ -11,6 +12,7 @@
 
 import tkinter.ttk as ttk
 import tkinter as tk
+import json
 
 
 if TYPE_CHECKING:
@@ -116,7 +118,7 @@ def cast_type(cls, value: Any, types: Iterable):
         """
 
         CAST_FUNTIONS = {
-            # dict: lambda v: convert_dict_to_object_info(json.loads(v))
+            dict: lambda v: convert_to_object_info(json.loads(v))
         }
 
         # Validate literals
@@ -141,14 +143,26 @@ def cast_type(cls, value: Any, types: Iterable):
 
     @classmethod
     def convert_types(cls, types_in):
-        def remove_wrapped(types: list):
+        """
+        Type preprocessing method, that extends the list of types with inherited members (polymorphism)
+        and removes classes that are wrapped by some other class, if the wrapper class also appears in
+        the annotations.
+        """
+        def remove_classes(types: list):
             r = types.copy()
             for type_ in types:
                 # It's a wrapper of some class -> remove the wrapped class
                 if hasattr(type_, "__wrapped__"):
                     if type_.__wrapped__ in r:
                         r.remove(type_.__wrapped__)
 
+                # Abstract classes are classes that don't allow instantiation -> remove the class
+                # Use the __bases__ instead of issubclass, because ABC is only supposed to denote
+                # classes abstract if they directly inherit it. In the case of multi-level inheritance
+                # issubclass would still return True, even though type_ is not a direct subclass ABC.
+                if ABC in type_.__bases__:
+                    r.remove(type_)
+
             return r
 
         while get_origin(types_in) is Union:
@@ -163,12 +177,15 @@ def remove_wrapped(types: list):
         # Also include inherited objects
         subtypes = []
         for t in types_in:
-            if hasattr(t, "__subclasses__") and t.__module__.split('.', 1)[0] in {"_discord", "daf"}:
+            if cls.get_cls_name(t) in __builtins__:
+                continue  # Don't consider built-int types for polymorphism
+
+            if hasattr(t, "__subclasses__"):
                 for st in t.__subclasses__():
                     subtypes.extend(cls.convert_types(st))
 
-        # Remove wrapped classes (eg. wrapped by decorator)
-        return remove_wrapped(types_in + subtypes)
+        # Remove wrapped classes (eg. wrapped by decorator) + ABC classes
+        return remove_classes(types_in + subtypes)
 
     def init_main_frame(self):
         frame_main = ttk.Frame(self)