Kaba class Song ed

class Song extends Object
    var bars: BarCollection
    var filename: Path
    var sample_rate: i32
    var samples: shared![Sample][]
    var secret_data: any
    var tags: Tag[]
    var tracks: shared![Track][]
    var volume: f32

    # constructors
    func mut __init__(session: Session, sample_rate: i32)

    # functions
    func mut add_bar(index: i32, b: Bar, mode: EditMode)
    func mut add_pause(index: i32, length: i32, mode: EditMode)
    func mut add_sample(s: Sample)
    func mut add_track(type: SignalType, index: i32) -> shared![Track]
    func mut begin_action_group(name: string)
    func mut delete_bar(index: i32, affect_midi: bool)
    func mut delete_sample(s: Sample)
    func mut delete_track(index: i32)
    func mut edit_bar(index: i32, b: Bar, mode: EditMode)
    func mut end_action_group()
    func get_time_str(t: i32) -> string
    func get_time_str_fuzzy(t: i32, dt: f32) -> string
    func get_time_str_long(t: i32) -> string
    func selfref layers() -> TrackLayer&[]
    func range() -> Range
    func mut redo() -> bool
    func mut reset_history()
    func selfref time_track() -> Track*
    func mut undo() -> bool