Swift way to explore OO and functional design patterns


Swift design playgrounds

I started this collection of playgrounds as notes in the process of learning object oriented design course, so that I can understand concepts better in Swift instead of Java (which instructor used).

I suddenly finish course and realize, that I want to learn more, bridge basics I learnet to practice in Swift and keep this playgrounds up to date. I will kindly appreciate any help to made this collection complete and comprehensible.

Moreover I realize that Swift is an opportunity to reevalute some classical object oriented design patterns in light of practical functional approach. I will keep updating this collection on my way to learn what it actually means.


I want to keep each playground resonably short and self explained. I keep "motivation" section and basic implementation in a playground file with pattern name, than more native for Swift or specific variants in additional playgrounds named by convention "Pattern name - Specific".

State Machine and State Machine - Native are best examples so far.


Course: Object-Oriented Design with Simon Allardice

Course: Design Patterns with Elisabeth Robson and Eric Freeman

Blog Post: Immutable Swift

"A truth that all programmers know: state management is why we get paid."

Blog post: Singleton Considered Stupid by Stevey Drunken

"The problem is, about 1/3 to 1/2 of them were basically cover-ups for deficiencies in C++ that don't exist in other languages. Although I'm not a huge Perl fan anymore, I have to admit the Perl community caught on to this first (or at least funniest). They pointed out that many of these so-called patterns were actually an implementation of Functional Programming in C++.

The Visitor, for instance, is just a class wrapper for a function with some accumulator variables, something that's achieved far more cleanly with, say, the map() function in higher-level languages. Iterator is a poor man's Visitor. The Strategy pattern is beautiful on the surface, but Strategy objects are typically stateless, which means they're really just first-order functions in disguise. (If they have state, then they're Closures in disguise.) Etc. You either get this, because you've done functional programming before, or you don't, in which case I sound like I'm a babbling idiot, so I guess I'll wrap it up."

TODO: Decompress second paragraph to actual examples in Swift?

Book: Head First Design Patterns

TODO: Port all examples covered in the book (authors kindly argeed)

Book: Functional Programming in Swift

TODO: Understand what it really mean for mankind

More Playgrounds

Design Patterns implemented in Swift – another collection of patterns implementations. Without unrelated comments and awful spelling.