[swift-evolution] for-else syntax
Sean Heber
sean at fifthace.com
Wed Feb 1 13:38:49 CST 2017
I usually use guard (or sometimes if) and an early return:
func run() {
guard !names.isEmpty else {
/* stuff */
return
}
/* stuff with names */
}
l8r
Sean
> On Feb 1, 2017, at 12:18 PM, Nicolas Fezans via swift-evolution <swift-evolution at swift.org> wrote:
>
> I tend to write this kind of treatment the other way around...
>
> if names.isEmpty {
> // do whatever
> } // on other cases I might have a few else-if to treat other cases that need special treament
> else {
> for name in names {
> // do your thing
> }
> }
>
>
> Nicolas Fezans
>
>
>
> On Wed, Feb 1, 2017 at 6:31 PM, Saagar Jha via swift-evolution <swift-evolution at swift.org> wrote:
> If you’re fine with a couple extra characters, you can use .isEmpty:
>
> for name in names {
> // do your thing
> }
> if names.isEmpty {
> // do whatever
> }
>
> It’s a bit more typing, but I feel it makes your intentions more clear.
>
> Saagar Jha
>
>> On 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
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>
>
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