// these tests require Swift 5.7 or so, and currently require the
// `-enable-bare-slash-regex` compiler flag.

// --- stubs ---

struct AnyRegexOutput {
}

protocol RegexComponent<RegexOutput> {
	associatedtype RegexOutput
}

struct Regex<Output> : RegexComponent {
	struct Match {
	}

	init(_ pattern: String) throws where Output == AnyRegexOutput { }

	func firstMatch(in string: String) throws -> Regex<Output>.Match? { return nil }

	typealias RegexOutput = Output
}

extension BidirectionalCollection {
	func contains(_ regex: some RegexComponent) -> Bool { return false }
	func firstMatch<Output>(of r: some RegexComponent<Output>) -> Regex<Output>.Match? { return nil } // slightly simplified
	func firstMatch<Output>(of r: some RegexComponent) -> Regex<Output>.Match? where SubSequence == Substring { return nil }
	func firstRange(of regex: some RegexComponent) -> Range<Self.Index>? { return nil }
	func matches<Output>(of r: some RegexComponent<Output>) -> [Regex<Output>.Match] { return [] } // slightly simplified
	func prefixMatch<R>(of regex: R) -> Regex<R.RegexOutput>.Match? where R: RegexComponent { return nil }
	func ranges(of regex: some RegexComponent) -> [Range<Self.Index>] { return [] }
	func starts(with regex: some RegexComponent) -> Bool { return false }
	func trimmingPrefix(_ regex: some RegexComponent) -> Self.SubSequence { return self.suffix(0) }
	func split(separator: some RegexComponent, maxSplits: Int = .max, omittingEmptySubsequences: Bool = true) -> [Self.SubSequence] { return [] }
}

extension String : RegexComponent {
	typealias Output = Substring
	typealias RegexOutput = String.Output
}

// --- tests ---

func myRegexpMethodsTests() throws {
	let input = "abcdef"
	let regex = try Regex(".*")

	// --- BidirectionalCollection ---

	_ = input.contains(regex)
	_ = input.firstMatch(of: regex)
	_ = input.firstRange(of: regex)
	_ = input.matches(of: regex)
	_ = input.prefixMatch(of: regex)
	_ = input.ranges(of: regex)
	_ = input.starts(with: regex)
	_ = input.trimmingPrefix(regex)
	_ = input.split(separator: regex)

	// --- compile time regexps ---

	let regex2 = /a*b*/
	_ = try regex2.firstMatch(in: input)

	let regex3 = /(?<varname>a*)*b/
	_ = try regex3.firstMatch(in: input)

	let regex4 = #/a*b*/#
	_ = try regex4.firstMatch(in: input)

	_ = input.contains(/a*b*/)
}