operators and external parameters


(Ray Fix) #1

When defining an operator such as == you can implicitly specify external parameters:

struct Path: Equatable {
    var value: String

    static func ==(lhs: Path, rhs: Path) -> Bool {
        return lhs.value == rhs.value
    }
}

Is this considered okay, or is it bad form and it should really be defined:

struct Path: Equatable {
    var value: String

    static func ==(_ lhs: Path, _ rhs: Path) -> Bool {
        return lhs.value == rhs.value
    }
}

Both seem to work fine in practice… :thinking:

Thank you!
Ray


(Ben Cohen) #2

Dunno about good form, but the std lib universally employs the _-less variant if that helps:

https://github.com/apple/swift/blob/master/stdlib/public/core/Character.swift#L404

The _ certainly seem like clutter to me.

Same for subscripts, which have similar behavior.

···

On Jan 24, 2017, at 10:14 AM, Ray Fix via swift-users <swift-users@swift.org> wrote:

When defining an operator such as == you can implicitly specify external parameters:

struct Path: Equatable {
    var value: String

    static func ==(lhs: Path, rhs: Path) -> Bool {
        return lhs.value == rhs.value
    }
}

Is this considered okay, or is it bad form and it should really be defined:

struct Path: Equatable {
    var value: String

    static func ==(_ lhs: Path, _ rhs: Path) -> Bool {
        return lhs.value == rhs.value
    }
}

Both seem to work fine in practice… :thinking:

Thank you!
Ray
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