How to use Swift documentation comments

Question

I have a few questions about Swift documentation comments:

1. Is there a way to make a Related declarations section like some of the Apple documentation has? For example, when I Option+Click the tablewView(_:heightForRowAtIndexPath:) method, it links me to three other related methods within the generated documentation.

2. Is there any warning tag in Swift? I know Objective-C allowed me to do @warning and get a bolded warning in the generated documentation. However, :warning: does nothing in Swift's documentation comments, so I was curious if there was another way.

3. Is there a way to make my documentation into an HTML file that is a similar format as the Apple Documentation? I know in other IDEs, such as Eclipse, I can generate HTML documentation for my code. Does XCode have this?

Answer 1

This answer was last revised for Swift 5.2 and Xcode 11.4.

---

You can use markup to write standard code documentation (using /// or /** */) and rich playground documentation (using //: or /*: */).

/// This function returns a welcoming string for a given `subject`.
///
/// ```
/// print(hello("World")) // Hello, World!
/// ```
///
/// - Warning: The returned string is not localized.
/// - Parameter subject: The subject to be welcomed.
/// - Returns: A hello string to the `subject`.
func hello(_ subject: String) -> String {
    return "Hello, \(subject)!"
}

As for documenting related symbols, there is a SeeAlso markup tag but requires you to write an explicit URL to your related symbol's documentation page.

If you want to generate HTML documentation index for your project, I recommend checking out jazzy and swift-doc. They're both amazing open-source projects, and are even used by Apple itself.