Add initial version of chapter 11's summary

11_classes/05_summary.ipynb

@@ -0,0 +1,100 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "# Chapter 11: Classes & Instances (TL;DR)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "skip"
+    }
+   },
+   "source": [
+    "With the `class` statement, we can create a *user-defined* data type that we also call a **class**.\n",
+    "\n",
+    "Then, to create new **instances** of the data type, we simply call the class, just as we do with the built-in constructors.\n",
+    "\n",
+    "Conceptually, a class is the **blueprint** defining the **behavior** each instance exhibits.\n",
+    "\n",
+    "In the example used throughout the chapter, the `Vector` and `Matrix` classes implement the linear algebra rules all `Vector` and `Matrix` instances follow *in general*. On the contrary, the instances **encapsulate** the **state** of *concrete* vectors and matrices.\n",
+    "\n",
+    "The `class` statement acts as a *namespace* that consists of simple *variable assignments* and *function definitions*:\n",
+    "1. Variables become the **class attributes** that are shared among all instances.\n",
+    "2. Functions may take a different role:\n",
+    "   - By default, they become **instance methods** by going through a **binding process** where a reference to the instance on which the method is *invoked* is passed in as the first argument. By convention, the corresponding parameter is called `self`; it embodies an instance's state: That means that instance methods set and get **instance attributes** on and from `self`.\n",
+    "   - They may be declared as **class methods**. Then, the binding process is adjusted such that the first argument passed in is a reference to the class itself and, by convention, named `cls`. A common use case is to design **alternative constructors**.\n",
+    "   - They may also be declared as **properties**. A use case for that are *derived* attributes that follow semantically from an instance's state.\n",
+    "   \n",
+    "The **Python Data Model** concerns what special methods (i.e., the ones with the dunder names) exists and how they work together.\n",
+    "\n",
+    "The instantiation process is controlled by the `.__init__()` method.\n",
+    "\n",
+    "The `__repr__()` and `__str__()` methods implement the **text representation** of an instance, which can be regarded as a Unicode encoded representation of all the state encapsulated in an instance.\n",
+    "\n",
+    "**Sequence emulation** means that a user-defined data type exhibits the same four properties as the built-in sequences, which are regarded as finite and iterable containers with a predictable order. The `.__len__()`, `.__iter__()`, `__reversed__()`, `__getitem__()`, and some others are used to implement the corresponding behaviors.\n",
+    "\n",
+    "Similarly, **number emulation** means that an instance of a user-defined data type behaves like a built-in number. For example, by implementing the `.__abs__()` method, an instance may be passed to the built-in [abs() <img height=\"12\" style=\"display: inline-block\" src=\"../static/link/to_py.png\">](https://docs.python.org/3/library/functions.html#abs) function.\n",
+    "\n",
+    "If different data types, built-in or user-defined, share a well-defined set of behaviors, a single function may be written to work with objects of all the data types. We describe such functions as **polymorphic**.\n",
+    "\n",
+    "Classes may specify how *operators* are **overloaded**. Examples for that are the `.__add__()`, `.__sub__()`, or `.__eq__()` methods.\n",
+    "\n",
+    "**Packages** are folders containing **modules** (i.e., \\*.py files) and a \"*\\_\\_init\\_\\_.py*\" file. We use them to design coherent libraries with reusable code."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.6"
+  },
+  "livereveal": {
+   "auto_select": "code",
+   "auto_select_fragment": true,
+   "scroll": true,
+   "theme": "serif"
+  },
+  "toc": {
+   "base_numbering": 1,
+   "nav_menu": {},
+   "number_sections": false,
+   "sideBar": true,
+   "skip_h1_title": true,
+   "title_cell": "Table of Contents",
+   "title_sidebar": "Contents",
+   "toc_cell": false,
+   "toc_position": {
+    "height": "calc(100% - 180px)",
+    "left": "10px",
+    "top": "150px",
+    "width": "384px"
+   },
+   "toc_section_display": false,
+   "toc_window_display": false
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}

CONTENTS.md

@@ -289,3 +289,4 @@ If this is not possible,
       (Writing one's own Packages;
        The final `Vector` & `Matrix` Classes;
        Comparison with `numpy`)
+    - [summary <img height="12" style="display: inline-block" src="static/link/to_nb.png">](https://nbviewer.jupyter.org/github/webartifex/intro-to-python/blob/develop/11_classes/05_summary.ipynb)