Just chiming in with you two: deinit for a struct doesn't really work because
structs are copied and destroyed all the time. Putting a file descriptor in a
struct (along with destruction logic) would fail pretty hard without C++-like
copy/move semantics.
Félix
> Le 23 déc. 2015 à 16:21:42, David Owens II via swift-evolution
> <swift-evolution@swift.org> a écrit :
>
> This is something I asked for before, then I realized it wouldn’t work.
>
> func helper(rs: ResourceHandle) {}
>
> let resource = ResourceHandle()
> helper(resource)
>
> result.doSomething() // error
>
> Another example:
>
> let x = Handle()
>
> do {
> let y = x
> } // resources are freed here as deinit is called
>
> // x is not safe to use, and freed again when x goes out of scope
>
> Everytime the struct value goes out of scope, the deinit would be called. The
> other option is to create move and copy semantics, as both would be required.
>
>> Given Swift’s emphasis on value types
>
> I think this is a mischaracterization, and one that I’ve made in the past.
> Swift’s emphasis in on clarity and providing you the mechanism to create
> things that are value-types for APIs that should behave like a value.
> However, that doesn’t mean that everything should a struct first.
>
> -David
>
>> On Dec 23, 2015, at 1:07 PM, Charles Srstka via swift-evolution
>> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:
>>
>> Introduction:
>>
>> This is a rather simple proposal, requesting that structs allow the ‘deinit’
>> destructor, as classes currently do.
>>
>> Motivation:
>>
>> Sometimes it is necessary to create an object that wraps a network
>> connection (that needs to be closed when the object is destroyed), or that
>> writes to a file on the disk (that has to be closed when the object is
>> destroyed). Often these objects will implement a close() method, but in the
>> case that the user forgets to call this before the object is disposed of, it
>> is good to call it in deinit just in case. However, deinit currently is
>> available only to classes and not to structs. This means that value types
>> currently cannot be used for network and file-backed constructs. Given
>> Swift’s emphasis on value types, it seems that it would be good to add this
>> functionality to value types.
>>
>> Proposed Solution:
>>
>> Allow the deinit destructor in structs.
>>
>> Impact on Existing Code:
>>
>> Should be no impact on existing code.
>>
>> Charles
>>
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>
>
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