FastfileDocument.swift

struct FastfileDocument: FileDocument {
    let fastfileContents: String

    init(contents: String) {
        self.fastfileContents = contents
    }

    init(configuration: ReadConfiguration) throws {
        // TODO: validate the file name
        guard let data = configuration.file.regularFileContents else { throw CocoaError(.fileReadCorruptFile) }
        guard let string = String(data: data, encoding: .utf8) else { throw CocoaError(.fileReadCorruptFile) }
        fastfileContents = string
    }

    static var readableContentTypes: [UTType] {
        return [UTType("public.data")!]
    }
    
    func fileWrapper(configuration: WriteConfiguration) throws -> FileWrapper {
        let data = fastfileContents.data(using: .utf8)!
        return FileWrapper(regularFileWithContents: data)
    }
    
    // MARK: Accessing Lanes
    
    func lanes() -> [Lane] {
        return FastfileParser.lanes(in: fastfileContents)
    }
}

struct Lane: Equatable, Identifiable {    
    let name: String
    let documentation: String

    var id: String {
        return name
    }
}