[swift-evolution] Colon vs. equals

[Haravikk]

+1 for changing attributes to using colons, as it would make them read more like a function call (albeit one with slightly different rules).

-1 though for changing dictionary literals; personally I think the colon syntax is a lot clearer, especially when the literal is being assigned, as it means there is only a single, clear assignment.

Regarding assigning new values to a dictionary though, I wonder if we might extend the literal syntax to modifying an existing dictionary? For example, I might do something like:

	myDictionary[“foo”: 1, “bar”: 2]	// Add/set new values for foo and bar

As this could be a neater way to replace:

	myDictionary[“foo”] = 1
	myDictionary[“bar”] = 2

Essentially we’d have a subscript for setting a single value, and one for setting a dictionary, without the need to do:

	myDictionary[[“foo”: 1, “bar”: 2]]

Since the second braces should be redundant I think. This would allow developers to avoid the use of assignments with dictionaries if they wish.

> On 6 Feb 2016, at 01:22, Maximilian Hünenberger via swift-evolution <swift-evolution at swift.org> wrote:
> 
> Inline
> 
> Am 06.02.2016 um 02:07 schrieb Brent Royal-Gordon <brent at architechies.com>:
> 
>>> If ":" should be replaced by "=" than only at the call site to make it more consistent with variable declaration and initialization:
>>> 
>>>       myFunc(number = 4, string = 7)
>>> 
>>>       func myFunc(number: Int, string: String) {}
>>> 
>>> Although writing "=" instead of ":" in methods in 1.5 years Swift and over 20 years Objective-C would be a huge change.
>> 
>> To be clear, I like colon in parameter lists; I don't see passing a parameter as setting something.
>> 
> 
> I cannot say whether I like ":" in parameter lists or if I'm just used to them...
> 
> Though setting parameters doesn't seem wrong to me. In fact value types get copied to a new parameter which is declared in the function signature.
> 
>> I suppose mainly what I'd like is for attributes to change:
>> 
>>   @available(iOS, introduced: 7.0, deprecated: 8.0)
>> 
>> And *possibly* for dictionary literals to change:
>> 
>>   let dict = ["key" = "value"]    // Also, the shorthand syntax would be [String = String]
>> 
>> Although dictionary literals seem like a relatively high-impact change compared to its value.
> 
> Yeah that would be true and also ":" in dictionaries reads to me like a "map this value to another one". So it would rather be "=>" than "=" which reads like an assignment to the left "<=".
> 
> - Maximilian
> 
>> 
>> -- 
>> Brent Royal-Gordon
>> Architechies
>> 
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