[swift-evolution] [Idea] Allow more operators as custom operators
brent at architechies.com
Mon Apr 11 01:03:36 CDT 2016
> `->`, `?` and `!` are used in types, but they are mostly unambiguous in expressions.
Sure, but types can appear in the middle of expressions. If we drop the `.self` requirement, a type name will *be* an expression. I don't think you can just ignore type names.
> The only use of `!` in expressions can be rewitten as a built-in operator function:
> postfix func ! <T> (left: T!) -> T
This doesn't work because you can assign through an `!`. For instance:
numberDictionary[key]! += 1
Once we have inout return values, we might be able to make `!` a normal postfix operator. (Actually, the same goes for `&`, which just becomes a way to leverage the implicit `&`ing of operator arguments into an explicit `&`ing.)
> `?` is used in optional method calls:
> A parallel proposal is going to remove such syntax from Swift, so this will not be a problem.
`?` is used for a lot more than that in expressions: optional chaining, the ternary operator, etc. None of them can be expressed as ordinary operators without significantly expanding operator syntax.
Sorry, I don't think we can make any real progress in this space without additional language features.
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