Kaba struct Ball ed

struct Ball extends SingleData
    var index: i32
    var is_selected: bool
    var is_special: bool
    var m_delta: bool
    var m_old: bool
    var pos: vec3
    var radius: f32
    var view_stage: i32

    # constructors
    func mut __init__(view_stage: i32, is_selected: bool, m_delta: bool, m_old: bool, is_special: bool, pos: vec3)

    # operators
    func mut __assign__(other: Ball)     # Ball = Ball