Word Scramble: Wrap up

Paul Hudson    @twostraws    October 25th 2019

This project was a last chance to review the fundamentals of SwiftUI before we move on to greater things with the next app. Still, we managed to cover some useful new things, not least List, onAppear, Bundle, fatalError(), UITextChecker, and more, and you have another app you can extend if you want to.

One thing I want to pick out before we finish is my use of fatalError(). If you read code from my own projects on GitHub, or read some of my more advanced tutorials, you’ll see that I rely on fatalError() a lot as a way of forcing code to shut down when something impossible has happened. The key to this technique – the thing that stops it from being recklessly dangerous – is knowing when a specific condition ought to be impossible. That comes with time and practice: there is no one quick list of all the places it’s a good idea to use fatalError(), and instead you’ll figure it out with experience.

Review what you learned

Anyone can sit through a tutorial, but it takes actual work to remember what was taught. It’s my job to make sure you take as much from these tutorials as possible, so I’ve prepared a short review to help you check your learning.

Click here to review what you learned in this project.

Challenge

One of the best ways to learn is to write your own code as often as possible, so here are three ways you should try extending this app to make sure you fully understand what’s going on:

1. Disallow answers that are shorter than three letters or are just our start word. For the three-letter check, the easiest thing to do is put a check into isReal() that returns false if the word length is under three letters. For the second part, just compare the start word against their input word and return false if they are the same.
2. Add a left bar button item that calls startGame(), so users can restart with a new word whenever they want to.
3. Put a text view below the List so you can track and show the player’s score for a given root word. How you calculate score is down to you, but something involving number of words and their letter count would be reasonable.

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