Operators functions storing in pointers

Using Swift
1

Good day

It's very convenient to have pointers to functions that can be stored for delayed (@escaping) execution:

struct Foo {

   func bar(argument: Int) {
   }

   func +(lhs: Foo, rhs: Foo) -> Foo {
   }

}



let foo = Foo().bar
foo(1)

But for operators is not possible to do same:
let foo = Foo().+

2

When referring to operators as function values, you sometimes have to enclose the operator in parentheses, like so: let foo = (+).

In addition, there are a few more errors in your code:

  • Operator methods (when the operator function is part of a type) have to be static, i.e. they don't get an implicit self parameter.
  • I don't think you can refer to a specific operator overload with Foo.(+) to distinguish it from all the other overloads of +.

This works:

struct Foo {
    static func +(lhs: Foo, rhs: Foo) -> Foo {
        // TODO: Implementation missing
        fatalError()
    }
}

// Add explicit type annotation to pick your overload
let add: (Foo, Foo) -> Foo = (+)
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