Coding Explorer Blog

Exploring how to code for iOS in Swift and Objective-C

Pattern Matching in Swift

Xcode 11.6 Swift 5.2.4

Last updated on

Pattern matching is a staple of functional languages.  At its core, Swift is primarily an object-oriented language, like Objective-C is.  However, there are many advantages to the way more functional style languages like Haskell and Erlang do things that the designers of Swift decided to include.  Pattern matching in particular, saves us having to type much longer, and less readable statements to do the same checks.

I mean, which is easier to read:

case (_, 0, 0):

or

if (someTuple.1 == 0) && (someTuple.2 == 0)

They both will find the same thing, but one can be used in a switch statement, and the other has to dig into the internals of a tuple and write a much longer looking comparison to 0 for each.  Not to mention the logical && there, to make sure both of them are true.
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Integers and Numeric Literals in Swift

Xcode 11.6 Swift 5.2.4

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Numbers are the building blocks of any piece of software.  It eventually gets all the way down to our code being translated into a series of numbers that refer to specific CPU instructions and data to use with them.  We will stay well above that level in this post, but I thought it would be useful to share some of the special aspects of how numbers, particularly Integers, are handled in Swift.
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Swift Set Type

Xcode 11.6 Swift 5.2.4

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In Objective-C there were three basic types of Data Structures, NSArray, NSDictionary, and NSSet.  In Objective-C, the immutable and mutable forms were separate, so you also had NSMutableArray, NSMutableDictionary, and NSMutableSet.  Especially since it is often an interview question, I should point out that a Data Structure is simply “a particular way of organizing data in a computer so that it can be used efficiently.”  You can read that sentence and more at the Wikipedia article about Data Structures.

In Swift we were greeted with Arrays and Dictionaries, but there was no Set to be found!  You had to go back to Objective-C’s NSSet to work with them.  You can read about the other two Data Structures back in the previous posts Arrays and their Methods in Swift and Swift Dictionary Quick Reference.  Well, thanks to Swift 1.2, Set has come to the land of Swift.
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Multiple Optional Bindings in Swift

Xcode 11.6 Swift 5.2.4

Last updated on

Shortly after my last post Segue from UITableViewCell Taps in Swift, Apple released Xcode 6.3 Beta 1, which includes Swift 1.2.  There are many updates to the language that I was quite happy about, but let’s talk about my favorite one today, improved Optional Binding.

The new version allows you to bind multiple optionals, as well as check a boolean expression related to them in a single line, avoiding the nesting we currently must do when working with multiple Optional Bindings.
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