Swift wants a greater language reference – Ole Begemann

In August 2020, I posted a rant on the Swift boards concerning the poor state of Swift documentation. Nothing got here of it, however I wish to reiterate one level I made then: the Swift challenge sorely wants a searchable, linkable language reference.

To be honest, Swift does have a language reference: the eponymous part in The Swift Programming Language (TSPL) accommodates a lot of the data I’d count on from such a useful resource. However that part isn’t properly structured to function an precise reference:

TSPL is just not searchable

The TSPL web site doesn’t have a search discipline. Even when it had one, I think about it might be a full-text search over the complete website, as is widespread (and acceptable) for a e book. A language reference wants a distinct search engine:

• Looking for key phrases (if, case, the place) should reliably discover the documentation for the key phrase as the highest consequence. I don’t wish to see the tons of of pages that comprise the phrase “if” of their physique textual content.

• I’d love to have the ability to seek for punctuation. Think about when you may seek for a logo reminiscent of # and it might present you an inventory of all syntax components that use this image. ^{This could be very informative and a good way to discover the language, not only for learners — particularly with good IDE integration (see under). Swift is such a giant and complicated language that most individuals gained’t know each language function.}

A language reference wants a search engine that is aware of to deal with key phrases and punctuation.

TSPL is just not linkable

Pages in TSPL are typically lengthy, with many separate gadgets crammed right into a single web page. For instance, all compiler attributes are documented on a single web page.

Sharing a hyperlink to a particular attribute, reminiscent of @resultBuilder, is tough if you already know your manner round HTML and just about not possible when you don’t (to not point out the unhealthy URL).

As a reader, opening such a hyperlink is disorienting because it drops you in the midst of a really lengthy web page, 95 % of which is irrelevant to you.

The reader expertise is even poorer once you arrive from a search engine (as most individuals would as a result of the location has no search operate): TSPL is likely one of the prime outcomes for swift resultbuilder on Google, but it surely drops you on the prime of the superlong web page on Attributes, with no indication the place to seek out the data you’re searching for.

Each language assemble, key phrase, attribute, and compiler directive ought to have its personal, linkable web page.

TSPL is structured mistaken

The Language Reference part in TSPL is organized as if it was written for parser or compiler builders. It makes use of the language’s grammar as a place to begin and branches out into expressions, statements, declarations, and so forth.

For instance:

I don’t find out about you, however as a consumer of the language, that’s not how I take into consideration Swift or how I seek for documentation.

Along with search engine, a language reference wants an alphabetical index of each key phrase or different syntax aspect, with hyperlinks to the respective element web page.

IDE integration

I used to be cautious to make this a grievance concerning the documentation for Swift and never concerning the (equally poor) state of Apple’s developer documentation. Swift is just not restricted to app improvement for Apple units, and I consider it’s important for Swift to place itself as a standalone challenge if it desires to be perceived as a viable general-purpose language.

It’s good that TSPL is hosted on swift.org and never developer.apple.com, and that’s additionally the place this new language reference I’m envisioning ought to reside. (I additionally suppose it’s mistaken to host the Swift API documentation on developer.apple.com.)

However as soon as now we have this language reference, Apple ought to in fact combine it into Xcode for offline search and context-sensitive assist. Think about when you may Possibility-click not solely identifiers however any token in a supply file to see its documentation.

A couple of examples:

• Clicking on if case let would clarify the sample matching syntax.
• Clicking on in would explains the assorted closure expression syntax variants.
• Clicking on #fileID would present you an instance of the ensuing string and evaluate it to #file and filePath.
• Clicking on @propertyWrapper would clarify what a property wrapper is and how one can implement one.
• Clicking on @dynamicMemberLookup would clarify its goal and what you need to do to implement it.
• Clicking on < in a generic declaration would clarify what generic parameters are and the way they’re used.
• Clicking on ? would present all language components that use a query mark (shorthand for Optionals, elective chaining, Elective sample matching, attempt?).
• Clicking on /// would listing the magic phrases Xcode understands in doc feedback.

You get the concept. This could be such a giant assist, not just for learners.

To summarize, that is the unhappy state of looking for language options in Xcode’s documentation viewer:

And this mockup exhibits the way it could possibly be: