CS193P IOS APPLICATION DEVELOPMENT SPRING 2020
Reading Assignment II:
Functional Programming
Objective
There’s not as big a volume of reading this week, but many of you might find the topics
this week a bit more dense and foreign to what you know (depending on your
experience, of course).
The primary goal is to understand the fundamental constructs in Swift that support
functional programming: protocols, extensions, generics and closures. An additional
important topic is Optionals. We’ve mentioned all of these things in lecture, but now
it’s time to study them.
Due
Ideally you should read all of the material referenced below by the start of Lecture 7
(if not sooner).
Materials
You’ll continue reading from the same document(s) (e.g. Swift Programming Language) as
last week.
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CS193P IOS APPLICATION DEVELOPMENT SPRING 2020
Swift Programming Language
Don’t gloss over reading any NOTE text (inside gray boxes) since many of those things are
quite important. However, if a NOTE refers to Objective-C or bridging, you can ignore it.
If you read something and don’t understand it, that’s what Piazza is for! Don’t be shy.
If there is a link to another section in the text, you don’t have to follow that link unless
what it links to is also part of this week’s reading assignment.
Always read the overview at the top of each major section (e.g., in The Basics, be sure to
read the part that starts “Swift is a new programming language for iOS …”).
You’ve read everything in A Swift Tour except the last two sections. We’ll postpone Error
Handling to next week (just to reduce volume this week).
Protocols and Extensions
Error Handling
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CS193P IOS APPLICATION DEVELOPMENT SPRING 2020
In the Language Guide area, read the following sections in the following chapters. It is
important to understand the information in these sections for you to be able to continue
to follow along in lecture, so don’t blow off this reading.
The Basics
Optionals are one of the “important topics of the week.”
Optionals
Error Handling
Basic Operators
This is related to Optionals and thus important.
Nil-Coalescing Operator
Strings and Characters
If you skipped this section last week, here’s another chance to read this. I suppose you
could push this yet again to next week, but try to squeeze it in if you have time.
String Literals
Initializing an Empty String
String Mutability
Strings Are Value Types
Working with Characters
Concatenating Strings and Characters
String Interpolation
Unicode
Counting Characters
Accessing and Modifying a String
Substrings
Comparing Strings
Unicode Representations of Strings
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CS193P IOS APPLICATION DEVELOPMENT SPRING 2020
Collection Types
Set is not quite as commonly used as Array and Dictionary, but it has a lot of cool uses
(it’s sort of under-appreciated).
Sets
Performing Set Operations (and this)
Control Flow
Just finishing off a couple of interesting language features here.
Conditional Statements
Value Bindings
Where
Checking API Availability
Closures
Another of the “most important topics of the week.” Here you’ll read the remaining
parts leftover from last week. Definitely make sure you understand this entire topic (i.e.
both last week’s and this week’s reading in this section).
Capturing Values
Closures are Reference Types
Escaping Closures
Autoclosures
Enumerations
Read this entire section. Enumerations are also under-appreciated relative to structs and
classes, but judicious use of them can make certain code really clean. You almost
certainly find this to be true in your Assignment 3, so don’t skip this section!
Structures and Classes
No new reading in this section, but be certain you understand the difference between a
reference type and a value type.
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CS193P IOS APPLICATION DEVELOPMENT SPRING 2020
Properties
You’re finding out in the demos that computed properties are used a lot in SwiftUI.
Computed Properties
Property Observers
Property Wrappers
Methods
Only one section left here, but what it talks about is something we’re more likely to do in an
enumeration. Go ahead and read that section, but understand that you won’t be doing it that
often (I’ll try to demo it later in the quarter).
Instance Methods
Assigning to self Within a Mutating Method
Subscripts
Inheritance
We’re kind of going to gloss over object-oriented programming in Swift because (outside
of your ViewModel), you’re not going to use it much in SwiftUI. So I’ve left it gray again
to reduce volume this week.
Initialization
The section in yellow is a really nifty feature of Swift and one that can get you around the
Catch-22 of the inability to call functions on yourself while initializing a var. The gray
sections are us skipping over object-oriented programming to reduce bulk in this reading
assignment.
Initializer Delegation for Value Types
Class Inheritance and Initialization
Failable Initializers
Required Initializers
Setting a Default Property Value with a Closure or Function
Deinitialization
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Optional Chaining
This is part of understanding Optionals (one of the “most important topics this week”).
Read this entire section.
Error Handling
Type Casting
Nested Types
Nested Types in Action
Referring to Nested Types
Extensions
The first of three sections which cover the fundamentals of functional programming in
Swift. Your goal this week is really to try to let this concept of functional programming
sink in as you read these sections.
Extension Syntax
Computed Properties
Initializers
Methods
Subscripts
Nested Types
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Protocols
Ditto Extensions explanation above.
Protocol Syntax
Property Requirements
Method Requirements
Mutating Method Requirements
Initializer Requirements
Protocols as Types
Delegation
Adding Protocol Conformance with an Extension
Collections of Protocol Types
Protocol Inheritance
Class-Only Protocols
Protocol Composition
Checking for Protocol Conformance
Optional Protocol Requirements
Protocol Extensions
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CS193P IOS APPLICATION DEVELOPMENT SPRING 2020
Generics
Ditto above again.
We did not talk about generics as they apply to protocols themselves (i.e. the sections
about “associated types” below). I’m leaving that out this week (although doing so might
make some of the other sections refer to things you won’t have read) just because there’s
so much functional programming to absorb here, adding that is probably over the top.
The Problem that Generics Solve
Generic Functions
Type Parameters
Naming Type Parameters
Generic Types
Extending a Generic Type
Type Constraints
Associated Types
Generic Where Clauses
Extensions With a Generic Where Clause
Associated Types with a Generic Where Clause
Generic Subscripts
Automatic Reference Counting
Memory Safety
Access Control
Access Levels
Access Control Syntax
Custom Types
Subclassing
Constants, Variables, Properties, and Subscripts
Initializers
Protocols
Extensions
Generics
Type Aliases
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Swift API Guidelines
Read this Swift API Guidelines document in its entirety.
Read this over again this week. It should be starting to sink in. As the quarter
progresses, you should eventually become an expert namer of properties, methods and other Swift
constructs. This will require you to refer back to this document often.
Be sure to click everywhere that it says “MORE DETAIL”.
Pay special attention to the “Write a documentation comment” section.
Pay special attention to the “Follow case conventions” section.
Pay special attention to the entire “Argument Labels” section.
You can ignore (for now), points that reference Protocols. When we learn about Protocols
next week, be sure to check back with this document after that.
You can also ignore the final subsection of the final section “Special Instructions -> Take
extra care with unconstrained polymorphism”. We won’t be doing anything with the Any
and AnyObject types.
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