# Model-Defined Interfaces

### A Pattern for Better, Safer, and More Explicit API

October 24, 2022

Most iOS architectural patterns rely on protocols to define what data and behaviors (i.e. interfaces) will be available to client code. This is a perfectly workable approach, but it adds quite a bit of overhead in terms of creating the protocol and multiple conforming types.

For example:

protocol AuthenticationProvider . . .

# WWDC 2017 Wishlist

June 04, 2017

It's the night before WWDC and so while this post is pretty late, its technically not too late to be appropriate. But not having much time to type this up means that I'm not able to go into as much detail as I normally do for these wishes and they are all going into a single post.

Some interesting context going into WWDC . . .

# A Single Writer Pattern in Swift

### A Fun Experiment With Shared Mutable State and Lock-Free "Locking"

December 08, 2016

I was talking to a co-worker today about different ways to minimize the risks around having a single shared instance in any app that holds global values which can be read and written to from anywhere in the code.

The potential risks around global mutable state are discussed in lots of places, but some of the key problems are:

. . .

# Towards Better Unit Testing

December 04, 2016

Last year, I wrote a post about the problems with code coverage as a metric, and left the topic as “to be continued”, saying that I had some ideas for a better approach. Well, it's taken long enough, but here are the first pieces in that objective to evolve a better way to create and measure well-tested software.

# Swift-y Dependency Injection, Part Two

### Injecting unique, mutable and persistent property values

October 21, 2016

Update: The original approach and sample code in this post have been modified slightly — instead of every Injected instance defining its own storage for injected traits, the Injectable struct instead defines global storage for all Injected instances. This is to allow let / constant struct instances to be injected with a stored trait without . . .

# A Swift-y Approach to Dependency Injection

June 11, 2016

While I would guess that fewer iOS developers are concerned with Dependency Injection than say, Java developers, the concept has gained more steam on the platform as the practice of unit and integration testing has increased.

In short, Dependency Injection (or DI) consists of:

1. Making your structs or classes depend on . . .

# A Grand Unification Theory of iOS Styling

June 11, 2016

If you've been on a team developing iOS apps before, you've probably been involved in a discussion or outright debate about how to handle styling, or the visual appearance of the app. Here, roughly, are the three sides of that debate:

It's . . .