+1. The force unwrap operator is basically a runtime assert that enforces the
invariant that "this value should not be nil at this point of use, and if it is
nil the programmer made a mistake". It is a perfectly legitimate tool for
writing code that can't otherwise be expressed (cleanly or at all) using the
other type system constructs.
Likewise for all the other postfix-! keywords ('as!', 'try!', etc).
Austin
> On May 2, 2016, at 11:53 PM, Rod Brown via swift-evolution
> <swift-evolution@swift.org> wrote:
>
> I’m on the side of the ‘!’ at the moment.
>
> I see a lot of heat here going into hatred of the force unwrap operator, as
> if it should be avoided like the plague. I simply don’t see the need for such
> absolutism. It’s there for a reason.
>
> There are definitely use cases where use of the force unwrap operator is
> unsafe. Specifically, a lot of direct property access shouldn’t be done with
> it because of the fact that even if you check, another thread may come in,
> switch the variable to “nil” and all of a sudden you have a crash despite
> your best efforts.
>
> That said, if you properly reason about your code, the ! operator is a useful
> and reasonable access tool to unwrap the optional you know about.
>
> I certainly don't agree that we need a language construct purely so we can
> write verbose things as a big scary warning.
>
>
>> On 3 May 2016, at 4:41 PM, Dominik Pich via swift-evolution
>> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:
>>
>> ;) yes. I know I can write let x = y! but IMHO THAT is too brief again.
>> I like the fact that guard makes you look what you do… it is a little bit
>> like assert(x != nil)
>>
>> guard! let x = y
>>
>> it reads awesome and everybody can more easily see it is a potentially fatal
>> & important call
>>
>>> On May 3, 2016, at 1:38 AM, Jordan Rose <jordan_r...@apple.com
>>> <mailto:jordan_r...@apple.com>> wrote:
>>>
>>> We have that; it’s just ‘!’. :-)
>>>
>>> Jordan
>>>
>>>> On May 2, 2016, at 12:09, Dominik Pich via swift-evolution
>>>> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:
>>>>
>>>> Hello,
>>>> often the guard statement is used to only unwrap optionals. multiple
>>>> guards will cause a lot of ‘overhead’.
>>>> also often if it doesn’t work. there is no easy way we can gracefully
>>>> recover ;)
>>>>
>>>> so how about we do the same as with try/catch where you can use try! and
>>>> have a guard!
>>>>
>>>> the guard! could just throw an exception …
>>>>
>>>> regards
>>>> Dominik
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>>>
>>
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