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Justin Comstock
122 PointsI don't really understand the init part.
class Page { let story: Story typealias Choice = (title: String, page: Page)
var firstChoice: Choice?
var secondChoice: Choice?
init(story: Story) {
self.story = story
}
}
This seems meta to have story = story and so forth and I can't wrap my head around it.
1 Answer

andren
28,523 PointsThe important thing to understand is that self.story
and story
do not refer to the same variable. The self.story
variable points to the story
field that is defined at the top of the Page
class. While story
refers to the parameter of the init
method:
class Page {
let story: Story typealias // This is self.story
Choice = (title: String, page: Page)
var firstChoice: Choice?
var secondChoice: Choice?
init(story: Story) { // This is story (within the init method)
self.story = story
}
}
So self.story = story
is actually telling Swift to take the story
field that is defined in the Page
object and set it equal to the story
argument that is passed in to the init
method. This is needed because the story
parameter will only exist within the init
method, it won't be accessible outside it. This pattern of creating an attribute and then assigning it a value that is passed in though the init
method is pretty common in OOP languages.