json_filter/lexical.go

// Package filter ...
//
// Description : JSON 词法分析
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 2022-07-04 17:52
package filter

import (
	"encoding/json"
	"fmt"

	"github.com/pkg/errors"
)

// parseLexical 解析词法
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 18:11 2022/7/4
func parseLexical(jsonData string) ([]lexicalNode, error) {
	if len(jsonData) < 2 {
		return nil, errors.New("input data is not json")
	}
	lexicalList := make([]lexicalNode, 0)
	tmpStr := ""
	for _, itemChar := range jsonData {
		currentChar := string(itemChar)
		preChar := "-1"
		if len(lexicalList) > 0 {
			preChar = lexicalList[len(lexicalList)-1].Val
		}
		if inputCharIsToken(currentChar, preChar) {
			// 是关键词
			if len(tmpStr) > 0 {
				lexicalList = append(lexicalList, lexicalNode{
					Val:     tmpStr,
					IsToken: false,
				})
			}
			lexicalList = append(lexicalList, lexicalNode{
				Val:     currentChar,
				IsToken: true,
			})
		} else {
			// 不是关键词, 继续向后走
			tmpStr = tmpStr + currentChar
		}
	}
	byteData, _ := json.Marshal(lexicalList)
	fmt.Println("============ : ", string(byteData))
	return nil, nil
}

// inputCharIsToken 输入字符是否为关键字
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 18:15 2022/7/4
func inputCharIsToken(inputChar string, preChar string) bool {
	if preChar == escapeCharacterToken {
		// 前一个是转义符, 当前不是关键字
		return false
	}
	tokenCharList := []string{
		listLeftToken,
		listRightToken,
		objectLeftToken,
		objectRightToken,
		keyLeftRightToken,
		kvPairSplitToken,
		escapeCharacterToken,
	}
	for _, itemChar := range tokenCharList {
		if itemChar == inputChar {
			return true
		}
	}
	return false
}