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

Haravikk swift-evolution at haravikk.me
Sun May 22 02:28:16 CDT 2016

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> 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
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