I'm new to Swift sorry if this might seem too simple. But I could not find answer from anywhere.
I am trying to understand this syntax below. The code have = then {..}() why need () at the end and also = sign for ?
var productLines: [ProductLine] = { return ProductLine.productLines() }()
I understand that computed variable would be something like .. this below
var varA: [arrayOutput] { return someArray }
what exactly is ={ return something }() called or mean in swift ?
What you see there is a closure for setting the initial value of the variable. A closure can be described as an anonymous code block.
This is what your code looks like:
var productLines: [ProductLine] = { return ProductLine.productLines() }()
Let me expand your code like this:
var productLines: [ProductLine] = { () -> [ProductLine] in
return ProductLine.productLines()
}()
The closure itself consists of the following code
{ () -> [ProductLine] in
return ProductLine.productLines()
}
The two round brackets () are used to execute the closure.
So what you see is not a computed property. You are therefore able to change the value of productLines like this afterwards:
productLines = [ProductLine]()
If it was a computed property instead, you would get an error like this one:
Cannot assign to property: productLines is a get-only property
{ ... }is a closure (an inline function definition).()calls that function`.productLinesinitially with the result of the closure{ return ProductLine.productLines() }The()calls that closure function. So the value ofproductLinescan be overwritten later. So no, this is not a computed property.