[swift-evolution] [Proposal] Add property for negation to Bool

[Charlie Monroe]

If there is a proposal for this, I think it needs to be complete - i.e. adding:

var isFalse: Bool
var isTrue: Bool
var negatedValue: Self (on BooleanType)
var negatedBoolValue: Bool

In such terms, the BooleanType would be complete as you'd be able to express all boolean operations using functions/properties. The question is where would it be used. I do not think adding a negating variable at the end of several transformations is a good idea, perhaps something like this could be used in predicate programming...

> On May 22, 2016, at 9:30 AM, T.J. Usiyan via swift-evolution <swift-evolution at swift.org> wrote:
> 
> `var isFalse: Bool` seems like a nice resolution to me. no need for new keywords and it reads better than !foo
> 
> On Sun, May 22, 2016 at 3:28 AM, Haravikk via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
> I think this would make more sense if we were to get more characters in operators, such that we could also replace && with and, and || with or, this way we could make not an operator and write expressions like so:
> 
> 	if foo and not bar { … }
> 
> Otherwise as others have said this seems strange as a method. If you don’t find the leading exclamation mark very readable then you could instead do:
> 
> 	foo != true
> 
> It’s a few more characters, but it exists now and reads logically I think.
> 
>> On 21 May 2016, at 15:50, Антон Миронов via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> 
>> I found negation operator (!) the least detectable among the code. So I’ve decided to add property “not” to BooleanType (Swift 2.2) or Boolean on 3.0 with extension:
>> 
>> extension BooleanType {
>> 	var not: Bool { return !self.boolValue }
>> }
>> 
>> This is code with negation operator:
>> 	return !self.lanes[position.y][currentLaneRange].contains(.Gap)
>> 
>> As I sad before negation operation is hard to spot. Moreover at first it looks like I’m trying to negate self for some reason.
>> 
>> This is code with “not” property:
>> 	return self.lanes[position.y][currentLaneRange].contains(.Gap).not
>> 
>> Now it is easy to spot the statement I am actually getting negation of.
>> On my experience negation operator can occasionally be missed while reading code. This happens less often with “not” property. So I’m proposing to add this property to standard library and prefer it in most cases.
>> 
>> Thanks,
>> Anton Mironov
>> 
>> _______________________________________________
>> swift-evolution mailing list
>> swift-evolution at swift.org <mailto:swift-evolution at swift.org>
>> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
> 
> 
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org <mailto:swift-evolution at swift.org>
> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
> 
> 
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.swift.org/pipermail/swift-evolution/attachments/20160522/27cc2cb6/attachment.html>