https://github.com/radex/battleship

My take on _Functional Programming in Swift_'s Battleship example
https://github.com/radex/battleship

Last synced: 3 days ago
JSON representation

My take on _Functional Programming in Swift_'s Battleship example

• Host: GitHub
• URL: https://github.com/radex/battleship
• Owner: radex
• Created: 2015-07-19T19:21:13.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2015-07-19T20:03:46.000Z (over 9 years ago)
• Last Synced: 2025-01-05T00:05:15.600Z (5 days ago)
• Language: Swift
• Size: 207 KB
• Stars: 11
• Watchers: 4
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
# Battleship

My take on [_Functional Programming in Swift's_][fpswift] Battleship example, using structs, Swift 2 protocol extensions and Core Graphics to render regions in a nicer way.

[fpswift]: http://www.objc.io/books/

Here's the code:

```swift

let circle1 = Circle(100).offset(200, 150)

let circle2 = Circle(80).offset(100, 200)

let enclosing = Circle(120).offset(160, 170)

let circle4 = Circle(50).offset(200, 150)

visualizer.region = circle1.plus(circle2).intersection(enclosing).minus(circle4)

```

Results (in pixel sampling and smart drawing modes):

![Pixel sampling](gh/sampling.png)

![Smart drawing](gh/smart.png)

The main difference with the book's example is that instead of dealing with `CGPoint -> Bool` matcher functions directly, I wrap them in a structs (conforming to a `RegionType` protocol). There are two nice things about this:

- you can use the more readable, nicely chainable method notation to transform regions

- in addition to the matcher function, a struct can also hold more information about the nature of the region

The second point means that `Circle` stores its radius, and `.offset`, `.plus`, `.intersection`, `.minus` return their own transformation structs that wrap the original regions and hold information about the transformation. This way, we can compose actual regions and draw them really nicely using Core Graphics.