[swift-evolution] [Accepted] SE-0121: Remove Optional Comparison Operators

Charlie Monroe charlie at charliemonroe.net
Sat Aug 27 08:58:30 CDT 2016

I have personally (ab)used this for the following:

class User {
	var email: String
	var firstName: String?
	var lastName: String?

You have a list of users based on email, so last name is optional. In Swift 2.x, you can do:

users.sort({ $0.lastName < $1.lastName })

Now, you need to do:

	guard let firstName = $0.0.lastName else {
		return true
	guard let secondName = $0.1.lastName else {
		return false
	return firstName < secondName

Which aside from being a brain teaser how to properly maintain ordering when $0.0's lastName != nil && $0.1's lastName == nil, adds additional few lines.

But I agree that it may come as confusing with Ints, etc. - with strings it kind of makes sense since nil is like an empty string which is placed in front of everything.

> On Aug 27, 2016, at 1:46 PM, Haravikk via swift-evolution <swift-evolution at swift.org> wrote:
>> On 27 Aug 2016, at 02:01, Kevin Ballard via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> This change is going to have a HUGE impact for me. I use this sort of comparison _all the time_ and find it incredibly useful, and have had literally zero bugs caused by this. Surely I can't be the only one who uses this. I am not looking forward to copying & pasting a reimplementation of the comparison functions into every single project I work on.
> Can you give some examples as to how this will have such a huge impact? Now that we have the ?? operator it seems that this is fairly easy to replace:
> 	value < 5 // where value is of type Int?
> With:
> 	(value ?? 0) < 5
> The latter is completely clear what the behaviour of nil is.
> Also, you can still re-add the operators where you need them, ideally with as limited a type as possible so you can make sure that it's behaviour is well defined.
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