[swift-evolution] for-else syntax

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collection ifEmpty:[ "...."  ] ifNotEmptyDo: [:each | "...." ]



> On Feb 1, 2017, at 10:29, Chris Davis via swift-evolution <swift-evolution at swift.org> wrote:
> 
> ah! I forgot about the break semantics, that’s definitely one for the con list.
> 
> I like Nicolas’ solution, clear to read.
> 
>> On 1 Feb 2017, at 18:18, Nicolas Fezans <nicolas.fezans at gmail.com <mailto:nicolas.fezans at gmail.com>> 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 <mailto: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 <mailto: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 <mailto:swift-evolution at swift.org>
>>> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
>> 
>> 
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>> 
> 
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