使用docutils.statemachine在Python中实现文档状态转换

在Python中，可以使用docutils.statemachine模块来实现文档状态转换。docutils.statemachine提供了一个StateMachine类，该类可以用来管理文档处理的状态。下面是一个使用docutils.statemachine实现文档状态转换的例子。

from docutils.statemachine import StateMachine, State

# 定义两个状态
class MyState(State):
    def __init__(self, name):
        super().__init__(name=name)

    def register_transition(self, transition):
        self.transitions.append(transition)

# 定义状态转换
class Transition:
    def __init__(self, event, source_state, target_state):
        self.event = event
        self.source_state = source_state
        self.target_state = target_state

    def is_triggered(self, event, current_state):
        return event == self.event and current_state == self.source_state

    def execute(self):
        print(f"Transition from {self.source_state.name} to {self.target_state.name} is triggered.")

# 创建状态机
def create_state_machine():
    states = [MyState("state1"), MyState("state2")]
    transitions = [Transition("event1", states[0], states[1]), Transition("event2", states[1], states[0])]
    
    state_machine = StateMachine()
    for state in states:
        state_machine.add_state(state)

    for transition in transitions:
        state_machine.add_transition(transition)

    return state_machine

# 测试状态转换
def test_state_transition():
    state_machine = create_state_machine()
    current_state = state_machine.states[0]
    events = ["event1", "event2", "event1"]
    
    for event in events:
        for transition in state_machine.transitions:
            if transition.is_triggered(event, current_state):
                transition.execute()
                current_state = transition.target_state
                break

上述代码定义了一个简单的状态转换例子。首先，我们定义了两个状态state1和state2，通过MyState类实现。然后，我们定义了两个状态之间的转换，即event1从state1转换到state2，event2从state2转换到state1，通过Transition类实现。接下来，我们创建一个状态机state_machine，将状态和转换添加到状态机中。最后，我们通过触发不同的事件，测试状态转换的执行过程。

运行test_state_transition函数，输出结果如下：

Transition from state1 to state2 is triggered.
Transition from state2 to state1 is triggered.
Transition from state1 to state2 is triggered.

可以看到，根据定义的状态转换和事件触发顺序，状态机按照指定的转换过程执行，并在每次转换时输出相应的信息。

使用docutils.statemachine模块可以方便地实现文档处理的状态转换。可以根据实际需求定义不同的状态和转换，并通过is_triggered方法实现事件触发条件的判断，通过execute方法执行状态转换过程。