Add API to enable or disable bare slash regex parsing

[ahoppen]

Depends on swiftlang/swift#59018

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Add a parameter to the SyntaxParser.parse functions to enable or disable bare slash regex parsing.

rdar://93750821

[ahoppen]

swiftlang/swift#59018

@swift-ci Please test

[rintaro]

I feel like these should be a Options object. But I'm not sure how the API should look like, for example

// An array of enums
SyntaxParse.parse(
    url,
    options: [.languageVersion("5.6"), .bareSlashRegexLiteral(true)],
    diagnosticHandler: diagnosticHandler)

// Just a "options" object
SyntaxParse.parse(
    url,
    options: SyntaxParseOptions(languageVersion: "5.1", enableBareSlashRegexLiteral: true),
    diagnosticHandler: diagnosticHandler)

The advantage of options object is that you can easily pass around and store the object in the clients, when they want to create options at not exact the call site.

WDYT?

[allevato]

Though it's still only in the pitch phase, it seems like a long-term API for this should build on the ideas from @DougGregor 's future feature strings.

The value passed into SyntaxParser.parse could just be an array of strings denoting the feature names. While that's not as discoverable as strongly-typed arguments, if Swift Package Manager is already planning to use that approach (for the reasons described in that pitch), then the string array would at least be familiar and consistent for users. And it eliminates some potential instability from API users, since SwiftSyntax doesn't need to be updated every time new features are added.

This would also have the advantage of letting SwiftSyntax clients, like swift-format, provide the same -enable-future-feature flag and pass those strings verbatim to SwiftSyntax, instead of each client having to either provide their own flags for each of these features or do their own mapping.

With all that being said, I don't know what the best design for this API should look like now if you want to land it before the future-feature work while still keeping that as the eventual end state.

[rintaro]

Alex and I chatted about this and we decided to accept this as is for now until the "language features" proposal is settled.

[rintaro]

Just resolve the conflict :)

[ahoppen]

swiftlang/swift#59018

@swift-ci Please test