[swift-evolution] for-else syntax

Jacob Bandes-Storch jtbandes at gmail.com
Wed Feb 1 11:17:10 CST 2017


One possible con: this is subtly but extremely different from Python, where
a for loop's else clause is executed only if there was no `break` from the
loop.
On Wed, Feb 1, 2017 at 8:48 AM Chris Davis via swift-evolution <
swift-evolution at swift.org> wrote:

> Hi,
>
> Often when I’m programming I stumble upon this scenario:
>
> I have a list of items that may or may not be empty - if it’s full, I do
> one thing, if it’s empty I do something else, my code looks like this:
>
> class Example_1
> {
>     let names = ["Chris", "John", "Jordan"]
>
>
>     /// Loop over names, if no names, print no names
>     func run()
>     {
>         for name in names
>         {
>             print(name)
>         }
>
>
>         if names.count == 0
>         {
>             print("no names")
>         }
>     }
> }
>
> let exampleOne = Example_1()
> exampleOne.run()
>
> However, Personally, I would find it more pleasing to write something like
> this:
>
> class Example_2_Proposed
> {
>     let names:[String] = []
>
>
>     /// Loop over names, if no names, print no names
>     func run()
>     {
>         for name in names
>         {
>             print(name)
>         } else {
>             print("no names")
>         }
>     }
> }
>
> let exampleTwo = Example_2_Proposed()
> exampleTwo.run()
>
> The difference here is a “for-else” type syntax where if there were no
> items in the array it would simply fall through to the else statement.
>
> What would be the pros/cons of introducing such syntax?
>
> Is there’s a way of doing something similar in swift already?
>
> Thanks
>
> Chris
>
>
>
>
> _______________________________________________
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> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution
>
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