[swift-evolution] Proposal: change infix operator attributes syntax to be more consistent with the rest of the language

Kevin Lundberg kevin at klundberg.com
Mon Mar 7 19:41:35 CST 2016

If you think of modelling operator behavior representations like an
enum, then fixity naturally feels different compared to the other
behavioral parameters:

enum OpBehavior {
  case prefix
  case postfix
  case infix(associativity: OpAssociativity, precedence: UInt8)

enum OpAssociativity { case left, right, none }

The behavioral parameters only apply to infix; making them look like
they could apply to anything by making them syntactic siblings to fixity
may lead one to think they could all be applied everywhere.

What about a modification to what Erica suggested?:

operator += infix(associativity: left, precedence: 90, assignment) //
assuming that assignment needs to stay around for now

On 3/6/2016 4:55 PM, Radosław Pietruszewski wrote:
> I agree “infix operator” reads more naturally, but I find it a bit
> strange to split operator configuration into fixity prefix and other
> parameters in curly braces/parentheses.
> — Radek
>> On 06 Mar 2016, at 20:46, Kevin Lundberg via swift-evolution
>> <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> Personally I like the current way of declaring an operator's expected
>> "fixity" as it reads much more naturally:
>> infix operator += // reads "an infix operator named +="
>> when compared to 
>> operator += (infix) 
>> // or
>> operator += (fixity: infix) // reads as "an operator named += which
>> has a fixity of infix"

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