[swift-evolution] Symmetrical operators

[Karl]

> On 14 Nov 2016, at 12:48, Haravikk via swift-evolution <swift-evolution at swift.org> wrote:
> 
> I'm a +1 on the feature, though for simply handling symmetry it's not a super critical issue.
> 
> 
> I wonder though, when you start looking at symmetry is it worth looking at other patterns? For example, could symmetrical operators be covered by a broader multi-part operator definition?
> 
> I was thinking recently it would be convenient if I could define say a 3-dimensional point like so: <x, y, z>
> 
> In this case you're looking at a symmetric operator with two different components (opening and closing angle brackets) with the ability to take three arguments. Is there a way we could define and implement something along these lines? If so it would be very flexible, and potential allow us to unify all operators into a single format.
> 
> For example, you can thing of a prefix operator as being a leading symbol plus one argument, while a postfix is one argument plus a trailing symbol, a binary operator is an argument, a symbol and another argument, a symmetric operator is a leading symbol, an argument and a trailing symbol (doesn't have to be identical).
> 
> If we had a means of specifying operators in this way (as a complete pattern) we could do away with special cases of operators entirely, though they may be worth keeping for compatibility and as a shorthand.
> 
>> On 14 Nov 2016, at 09:57, Dimitri Racordon via swift-evolution <swift-evolution at swift.org> wrote:
>> 
>> +1
>> 
>> I think the use cases are not that sparse actually.
>> I would also argue that it would be easier to understand the intent of the code with some sort of keyword than with a hard copy of each function.
>> 
>> 
>> 
>>> On 14 Nov 2016, at 10:51, Anton Zhilin via swift-evolution <swift-evolution at swift.org> wrote:
>>> 
>>> -1
>>> Not worth adding syntactic sugar for a narrow use case. Plus it's an additive feature.
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Commutative operators are very common and I would definitely +1 a shorthand for them.

You seem to be talking about a custom literal, rather than an operator - you said you want to “define” a point with some special syntax. Try ArrayLiteralConvertible.

- Karl