Nested stack automaton 嵌套堆栈自动机
In automata theory, a nested stack automaton is a finite automaton that can make use of a stack containing data which can be additional stacks.
Like a stack automaton, a nested stack automaton may step up or down in the stack, and read the current symbol; in addition, it may at any place create a new stack, operate on that one, eventually destroy it, and continue operating on the old stack. This way, stacks can be nested recursively to an arbitrary depth; however, the automaton always operates on the innermost stack only.