SwiftLint/Source/SwiftLintFramework/Extensions/SourceFileSyntax+SwiftLint.swift

import SwiftSyntax

extension SourceFileSyntax {
    func windowsOfThreeTokens() -> [(TokenSyntax, TokenSyntax, TokenSyntax)] {
        Array(tokens)
            .windows(ofCount: 3)
            .map { tokens in
                let previous = tokens[tokens.startIndex]
                let current = tokens[tokens.startIndex + 1]
                let next = tokens[tokens.startIndex + 2]
                return (previous, current, next)
            }
    }
}