(swift) improvements: support some, @main; Fix # keywords .

[mportiz08]

General enhancements and a bug fix for highlighting Swift code.

Changes

Adds highlighting support for new Swift 5.1 and 5.3 features that are heavily utilized in SwiftUI code:

1. some keyword (Introduced in Swift 5.1)
2. @main attribute (Introduced in Swift 5.3)

Fixes a bug where keywords that start with the # character (like #endif as an example) are not matched.

Checklist

• Added markup tests
• Updated the changelog at CHANGES.md
• Added myself to AUTHORS.txt, under Contributors

[joshgoebel]

@svanimpe Could you take a quick look here. Does this look good to you? I think the changes look good, I just don't know the language itself.

@mportiz08 #2847

Do you know anything about c? If not and you agree would you mind yanking that out as part of this PR also?

[svanimpe]

I wonder if @mattt would be willing to help out here. Perhaps https://github.com/SwiftDocOrg/swift-doc can be used to generate a list of global functions in the Standard Library?

[joshgoebel]

There are a number of Swift issues open right now (many of them of the more trivial variety) if a Swift champion were to show up on the scene. :) #2825

[joshgoebel]

Perhaps https://github.com/SwiftDocOrg/swift-doc can be used to generate a list of global functions in the Standard Library?

I do worry that what we have now is perhaps someones list of "frequently used" rather than ever having been "all globals" (I really have no idea though), but now I'm curious. Swift is shipped as part of the common group so that makes me think about it's ultimate size perhaps a bit more than other grammars... like if we were suddenly going to add 1000 keywords that might be something we need to look at. Right now though Swift is a pretty small grammar, so we certainly have room to grow.

[joshgoebel]

If we're going to totally rewrite the keywords section overall I'd save that for another PR though and also switch to the new one keyword per line array style to make future maintenance easier.

[mportiz08]

Do you know anything about c? If not and you agree would you mind yanking that out as part of this PR also?

I don't, but that is really interesting/surprising—I'm honestly not aware of c being a keyword on its own. It looks like it was introduced with e5c1b0c.

[joshgoebel]

@natecook1000 You added c to the list of Swift keywords in e5c1b0c. Can you shed any light? :)

[joshgoebel]

Since we don't have any immediate answer on c I don't see a need for that issue to hold up this work. I glanced at the links provided and this looks entirely reasonable.

Thanks for the contribution!

[joshgoebel]

If you'd perhaps like to continue helping out with Swift: #2758 #2819

Now quite as low-hanging fruit, but close.

[svanimpe]

W.r.t. the built-ins: I've noticed that methods like Array.count also highlight because count is listed as a built-in, even though it's not a global function anymore.

[joshgoebel]

Well if the language has changed then count be perhaps removed but ultimately this will be solved when the Swift grammar adds property access and method dispatch since that rule matching would win prevent the keyword from matching, etc.