GC

collect() ->
    mark()
    sweep()

mark() ->
    for Field in Roots do
        Object = *Field
        if Object != null do
            push(LiveObjects, Object)
            push(WorkList, Object)

    while !empty(WorkList) do
          Object = pop(WorkList)
          for Field in Object do
              ReferencedObject = *Field
              if ReferencedObject != null and
                 !contains(LiveObjects, ReferencedObject) do
                 push(LiveObjects, ReferencedObject)
                 push(WorkList, ReferencedObject)

sweep() ->
    DeadObjects = complement(LiveObjects, AllObjects)
    while !empty(DeadObjects) do
          Object = pop(DeadObjects)
          free(Object)
    AllObjects = LiveObjects