I’ve only read the last couple of posts but has anybody already suggested using
something like this:
if let foo! {
// code that uses foo
}
People already know that the ! is unwrapping a value and that let is defining a
new constant. So why not combine those two?
Alternatively it could also be:
if let foo? {
// code that uses foo
}
What do you think?
– Cihat
> Am 19.12.2015 um 23:43 schrieb Dave Abrahams via swift-evolution
> <[email protected]>:
>
>>
>> On Dec 19, 2015, at 2:15 PM, Radosław Pietruszewski via swift-evolution
>> <[email protected] <mailto:[email protected]>> wrote:
>>
>> I was going to suggest something similar (a hard naming problem also):
>>
>> if has foo {
>> // foo is now unwrapped and non-optional
>> }
>>
>> guard has foo else { return }
>>
>> Does the same thing as `let foo = foo` in practice, but places it in a
>> somewhat different mental model. Instead of unwrapping and immediately
>> assigning to a new constant with the same name (which just looks kind of
>> silly, like some magic voodoo ritual), it sort of asserts that we “have” foo
>> (i.e. it’s not nil), and therefore from that point it can just be treated as
>> non-optional.
>>
>> IMHO this, although introduces a new keyword, makes more sense than trying
>> to reuse “let” in a context where it seems nonsensical. Perhaps this would
>> be closer to Swift’s goals, by reducing very common boilerplate, but without
>> harming clarity in a way adding a new meaning to “let” would.
>>
>> Curious to hear Chris Lattner’s opinion :-)
>
> IANACL (I am not a Chris Lattner) but, FWIW, several of us are uncomfortable
> with the idea that a single declared property might have different static
> types in different regions of code.
>
>>
>> — Radek
>>
>>> On 19 Dec 2015, at 21:31, Dennis Lysenko via swift-evolution
>>> <[email protected] <mailto:[email protected]>> wrote:
>>>
>>> What if we made the keyword "unwrap"?
>>>
>>> if unwrap someViewController {
>>> // now there is a shadowing nonoptional (unwrapped) variable of the same
>>> name only within this scope, boiling down to simple syntactic sugar for
>>> optional binding and it is fairly clear.
>>> }
>>>
>>>
>>> On Sat, Dec 19, 2015, 1:31 PM Kevin Wooten via swift-evolution
>>> <[email protected] <mailto:[email protected]>> wrote:
>>> As much fun as it to example with foo, I would argue the opposite when you
>>> use some real world variable names:
>>>
>>> if let someInterestingViewConroller = someInterestingViewConroller {
>>> }
>>>
>>> vs
>>>
>>> If let someInterestingViewConroller {
>>> }
>>>
>>> We know what let does and it should be enough to impart the necessary
>>> information for this statement.
>>>
>>> When it comes to newcomers I think you'd be hard pressed to find somebody
>>> who'd be able to understand either form without teaching; so not losing
>>> much there.
>>>
>>>
>>> On Dec 19, 2015, at 10:01 AM, Chris Lattner via swift-evolution
>>> <[email protected] <mailto:[email protected]>> wrote:
>>>
>>>>
>>>>> On Dec 11, 2015, at 8:19 AM, Jeff Kelley via swift-evolution
>>>>> <[email protected] <mailto:[email protected]>> wrote:
>>>>>
>>>>> I’ve had similar ideas to this. Instead of ditching the if let syntax
>>>>> altogether, another approach would be to use the existing name if no new
>>>>> name is given, so that this code:
>>>>>
>>>>> if let foo = foo { /* use foo */ }
>>>>>
>>>>> could become this code:
>>>>>
>>>>> if let foo { /* use foo */ }
>>>>>
>>>>> In both cases, foo is non-optional inside the braces. If you gave it
>>>>> another name with the if let syntax, that would work as it does today.
>>>>
>>>> Hi Jeff,
>>>>
>>>> This is commonly requested - the problem is that while it does help reduce
>>>> boilerplate, it runs counter to the goal of improving clarity.
>>>>
>>>> -Chris
>>>>
>>>>
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> -Dave
>
>
>
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