[swift-evolution] [Idea] if let value!

[Vladimir.S]

The idea to process the 'if' block only if anOptional is not null

In case of
let! anOptional {
}
IMO it is not clear that this block will be executed *only* if anOptional 
is not null.

if let! anOptional {
  // here only if anOptional != null
}
- seems like similar to standard 'if let' construction so should not 
confuse too much and IMO will be remembered after the first appearance/using.

On 18.05.2016 15:15, Daniel Höpfl via swift-evolution wrote:
> Would it be possible to drop the "if"? I don't see why we need it.
>
> On 2016-05-18 11:22, LM wrote:
>> I am experimenting with this:
>>
>> If var! anOptional {
>>    anOptional   // unwrapped, shadowing
>> }
>>
>> if let! anOptional {
>> ... // same
>> }
>>
>>
>> This compiler codebase is truly remarkable, so it should also works with
>>
>> If var! opt1 where opt1 < 27 {
>> }
>>
>> or
>>
>> if var! opt1, opt2 {
>>    // both unwrapped
>> }
>>
>> LM/
>>
>>
>>> On May 18, 2016, at 10:21 AM, Daniel Höpfl via swift-evolution
>>> <swift-evolution at swift.org> wrote:
>>>
>>> Just an idea: Why don’t we think about it similar to try?
>>>
>>> var anOptional : String?
>>>
>>> let? anOptional { /* use it, but cannot change it */ }
>>> let! anOptional { /* use it, without checking, cannot change it */ }
>>>
>>> var? anOptional { /* use it, can also change it, */ }
>>> var! anOptional { /* use it, without checking, can also change it */ }
>>>
>>> Is it allowed to set it to nil in the var case? Hard to say.
>>>
>>>> On 17.05.16 15:43, Vladimir.S via swift-evolution wrote:
>>>> It is common to shadow optional value name with unwrapped value with
>>>> same name:
>>>>
>>>> if let someGoodValue = someGoodValue {...}
>>>>
>>>> What if we'll have a syntax to not repeat the variable name to achieve
>>>> the same target:
>>>>
>>>> if let someGoodValue! {...}
>>>>
>>>> What do you think?
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