Could you clarify how to use `if case` to achieve the same target as
proposed `if let value!` ?
(btw, probably `if let value? {..}` will be better)
On 17.05.2016 18:18, Matthew Johnson wrote:
On May 17, 2016, at 10:13 AM, Tony Allevato via swift-evolution
<[email protected] <mailto:[email protected]>> wrote:
While I've sometimes (early on) wished for a shorter-hand syntax for that
construct, I've never been able to think of something that I thought was
better. I've gotten to the point where I don't particularly mind it anymore.
Regarding the exclamation point specifically, seeing one of those in an
expression context says to me "this thing will die horribly if it is
nil/throws an error". Using it in this context where that's not the case
would probably go against users' expectations.
Agree. If we are going have syntax similar to pattern matching it should
be the same as pattern matching. This would mean using ‘?' rather than
‘!’. However, we already have generalized pattern matching with `if case`
for that. This topic has been debated extensively.
On Tue, May 17, 2016 at 8:05 AM Vladimir.S via swift-evolution
<[email protected] <mailto:[email protected]>> wrote:
On 17.05.2016 16:51, Johan Jensen wrote:
> This was one of the first and most commonly suggested ideas, when
the Swift
> Evolution mailing list first started.
> Chris Lattner sums it up
>
<https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20151214/003546.html>
> in one of those threads:
>
>> This is commonly requested - the problem is that while it does help
> reduce boilerplate, it runs counter to the goal of improving clarity.
>
> — Johan
Oh, thank you for letting this know.
Well, I totally disagree with Chris. And as soon as there was no
'official'
proposal and 'official' decision, I'd like to discuss this more.
I saw a lot of code like
if let mySomeValue = mySomeValue {} in sources and even in books.
Plus, I really believe that
if let mySomeValue! {..} is better in any way: readability, less
space for
errors(when you need to repeat the same name) etc
FWIW, I suggest more explicit variant:
if let value! {...} // with exclamation mark
In that "old" proposal there was `if let value {...}`, was not so clear.
I can't accept an argument that you can use another name - as usually
'good' name is already 'crafted' for the instance and you want to use
it in
next code.
Otherwise, we need a 'best practice' to name optional variables with some
prefix or suffix like : mySomeValueOpt, then `if let mySomeValue =
mySomeValueOpt` will have a sense. But as I understand, we don't want to
use such approach.
Additionally, when you shadow optional value with same name - you are
*protecting* yourself from using optional value inside block of unwrapped
code. IMO it is a good idea.
And want we or don't want, we already have this practice widely. So I
believe this(my) proposal will improve the code.
I'd like to get opinion of the community regarding this feature.
On 17.05.2016 16:51, Johan Jensen wrote:
> This was one of the first and most commonly suggested ideas, when
the Swift
> Evolution mailing list first started.
> Chris Lattner sums it up
>
<https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20151214/003546.html>
> in one of those threads:
>
>> This is commonly requested - the problem is that while it does help
> reduce boilerplate, it runs counter to the goal of improving clarity.
>
> — Johan
>
> On Tue, May 17, 2016 at 3:43 PM, Vladimir.S via swift-evolution
> <[email protected] <mailto:[email protected]>
<mailto:[email protected]
<mailto:[email protected]>>> 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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<mailto:[email protected] <mailto:[email protected]>>
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>
>
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