[swift-evolution] Proposal Sketch: simplify optional unwrapping syntax

[Dave Abrahams]

> On Dec 19, 2015, at 1:41 PM, Dennis Lysenko <dennis.s.lysenko at gmail.com> wrote:
> 
> Shadowing is good in this case because it lets you capture constant values for the exact scope in which you need them.
> 
That is completely independent of shadowing.  You do that even if you choose different names inside the block from outside.
> This helps avoid overhead of repeated getters and method calls. Using shorter names is automatically less descriptive; otherwise, people would advocate using abbreviations in property names, which is a stylistic and readability faux pas.
> 
"More descriptive" ≠ "more readable".  When writing, we don't go into reams of detail about everything; we go into detail about the salient things.  We have pronouns for a reason, e.g. "when a person arriving at the refrigerator opens the door, she sees what's inside; then she decides whether she wants it."  "She" is a short name used in a localized context as a stand-in for a more-descriptive phrase, "a person arriving at the refrigerator".  Repeating the more descriptive phrase would harm readability.

> 
> On Sat, Dec 19, 2015, 4:34 PM Dennis Lysenko <dennis.s.lysenko at gmail.com <mailto:dennis.s.lysenko at gmail.com>> wrote:
> Disagree. Short names are less descriptive and less readable. And saying "shadowing is bad" without any argument is just silly for a mailing list.
> 
> 
> On Sat, Dec 19, 2015, 3:57 PM Dave Abrahams via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> On Dec 19, 2015, at 12:37 PM, ilya via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> 
>> I prefer 
>> 
>> if let vc = someInterestingViewConroller {
>>   vc.doSomething()
>> }
>> 
>> - Explicit is better than implicit
>> - shadowing is bad 
>> - now there's no ambiguity about how to change the original property. 
>> 
>> Therefore I'm -1 on any proposal that hides explicit name binding and/or increases shadowing, including let foo and unwrap foo. 
> 
> +1 to that.  IMO re-using the same name for the unwrapped version of an optional variable does not help readability, and I don't want to encourage it.  In a localized context like this, a short name is often better anyway as it declutters the code inside the block.
> 
>> 
>> On Sat, Dec 19, 2015 at 21:31 Kevin Wooten via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> 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 <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> 
>>> 
>>>> On Dec 11, 2015, at 8:19 AM, Jeff Kelley via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> 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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-Dave



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