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Kevin Lozandier
Courses Plus Student 53,747 PointsWhy named parameters aren't used when overriding swift struct initializers?
For Swift struct initializers, why is it unncesary to explicitly use the named parameters (such as #firstName, and #lastName) syntax when overriding init function?
struct Contact {
// Let will ensure values cannot be reassigned after initialization
let firstName: String
let lastName: String
var type: String = "Friend"
init(#firstName: String, #lastName: String) {
self.firstName =firstName
self.lastName = lastName
self.type = type
}
1 Answer
Francisco Navarro
14,185 PointsHi Kevin, I have found this in apple documentation. I haven't realised it until your question but now we know they have a particular role :). Hope that helps.
"Local and External Parameter Names
As with function and method parameters, initialization parameters can have both a local name for use within the initializer’s body and an external name for use when calling the initializer.
However, initializers do not have an identifying function name before their parentheses in the way that functions and methods do. Therefore, the names and types of an initializer’s parameters play a particularly important role in identifying which initializer should be called. Because of this, Swift provides an automatic external name for every parameter in an initializer if you don’t provide an external name yourself."
Kevin Lozandier
Courses Plus Student 53,747 PointsKevin Lozandier
Courses Plus Student 53,747 PointsHad a heard time finding this in the HTML version of the book, for some reason; do you mind sending me a link?
I saw it odd, when it was still validating as correct if I explicitly defined my named parameters (as you should for convenience initializers you may want to create).
Francisco Navarro
14,185 PointsFrancisco Navarro
14,185 PointsOf course I don't mind. Here's the link:
https://developer.apple.com/library/ios/documentation/swift/conceptual/Swift_Programming_Language/Initialization.html
With the left menu Initialization selected, look for "Local and External Parameter Names" header.
Kevin Lozandier
Courses Plus Student 53,747 PointsKevin Lozandier
Courses Plus Student 53,747 PointsThanks, Francisco Navarro.