dfa

确定有限状态自动机或确定有限自动机（deterministic finite automaton, DFA）

解决了什么问题

根据事先定义的配置信息,在每个节点状态下进行对应的状态转移

demo

start -> 1

1 -> 1 
1 -> 2
1 -> 3

2 -> 1
2 -> 2
2 -> 3

3 -> 1 
3 -> 2 
3 -> 3
3 -> end

start 没有入度,因此为初态,所有状态的起始位置
end 没有出度,因此为终态,所有状态的终止位置

// config meta.yaml 

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"

	"github.com/songzhibin97/dfa"
)

func main() {
	config, err := ioutil.ReadFile("./meta.yaml")
	if err != nil {
		panic("read meta.yaml error")
	}

	ndfa, err := dfa.NewDfa(string(config))
	if err != nil {
		panic("new dfa error")
	}
	s := dfa.NewStatus(ndfa)

	// 查看当前状态下可转移的选项 
	s.Peek() // [1]

	s.Transfer("bad") // false 

	// 转移到状态1
	s.Transfer("1")
	s.Peek() // [1,2,3]

	// 转移到状态3
	s.Transfer("3")
	s.Peek() // [1,2,3,end]

	s.Transfer("end")
	s.Peek() // []

	ns, _ := json.Marshal(s.Circulation())
	fmt.Println(string(ns))
	// 展示了所有的状态转移
	/*
		[
	    {
	        "id": "start",
	        "next": [
	            "1"
	        ],
	        "payload": "start",
	        "initial_state": true,
	        "final_state": false,
	        "after_call": [
	            "after1"
	        ],
	        "before_call": [
	            "before1"
	        ]
	    },
	    {
	        "id": "1",
	        "next": [
	            "1",
	            "2",
	            "3"
	        ],
	        "payload": "1",
	        "initial_state": false,
	        "final_state": false,
	        "after_call": [
	            "after2"
	        ],
	        "before_call": [
	            "before2"
	        ]
	    },
	    {
	        "id": "3",
	        "next": [
	            "1",
	            "2",
	            "3",
	            "end"
	        ],
	        "payload": "3",
	        "initial_state": false,
	        "final_state": false,
	        "after_call": [
	            "after1",
	            "after2",
	            "after3"
	        ],
	        "before_call": [
	            "before1",
	            "before2",
	            "before3"
	        ]
	    },
	    {
	        "id": "end",
	        "next": null,
	        "payload": "end",
	        "initial_state": false,
	        "final_state": true,
	        "after_call": null,
	        "before_call": null
	    }
	]

	*/

}