C#实现LR(0)文法项目集族构造算法

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Windows.Forms;

namespace LR0Parser
{
    public partial class Form1 : Form
    {
        private List<string> productions = new List<string>(); // 存储文法产生式
        private List<string> symbols = new List<string>(); // 存储文法符号
        private List<string> states = new List<string>(); // 存储状态
        private List<string> itemsets = new List<string>(); // 存储项目族

        private void button2_Click(object sender, EventArgs e) // 判别LR(0)文法
        {
            // 读取文法产生式
            if (Regex.Replace(richTextBox1.Text, '\s', '') == '')
            {
                MessageBox.Show('输入文法为空');
                return;
            }

            // 读取并处理文法产生式
            string[] lines = richTextBox1.Lines;
            foreach (string line in lines)
            {
                if (line.Trim() != '')
                {
                    string[] parts = line.Split(new char[] { '-', '>' }, StringSplitOptions.RemoveEmptyEntries);
                    string left = parts[0].Trim();
                    string right = parts[1].Trim();
                    if (!symbols.Contains(left))
                    {
                        symbols.Add(left);
                    }
                    string[] symbolsInRight = right.Split(new char[] { '|' }, StringSplitOptions.RemoveEmptyEntries);
                    foreach (string symbol in symbolsInRight)
                    {
                        productions.Add(left + '->' + symbol);
                        foreach (char c in symbol)
                        {
                            if (!symbols.Contains(c.ToString()))
                            {
                                symbols.Add(c.ToString());
                            }
                        }
                    }
                }
            }

            // 生成项目族
            BuilditemFamily();

            // 生成GOTO表和ACTION表
            // BuildTables();

            button4.Enabled = true;
            button5.Enabled = true;
            button6.Enabled = true;
        }

        private void button4_Click(object sender, EventArgs e) // 生成项目族信息
        {
            BuilditemFamily();

            // 显示状态和项目族信息
            listView1.Columns.Clear();
            listView1.Items.Clear();
            listView1.View = View.Details;

            // 添加列名
            listView1.Columns.Add('状态', 150);
            listView1.Columns.Add('项目集信息', 300);

            // 添加数据
            for (int i = 0; i < states.Count; i++)
            {
                ListViewItem lvi = new ListViewItem(states[i]);
                lvi.SubItems.Add(itemsets[i]);
                listView1.Items.Add(lvi);
            }
            listView1.GridLines = true;
        }

        private void BuilditemFamily()
        {
            // 清空之前的数据
            productions.Clear();
            symbols.Clear();
            states.Clear();
            itemsets.Clear();

            // 获取文法产生式和符号
            string[] lines = richTextBox1.Lines;
            foreach (string line in lines)
            {
                if (line.Trim() != '')
                {
                    string[] parts = line.Split(new char[] { '-', '>' }, StringSplitOptions.RemoveEmptyEntries);
                    string left = parts[0].Trim();
                    string right = parts[1].Trim();
                    if (!symbols.Contains(left))
                    {
                        symbols.Add(left);
                    }
                    string[] symbolsInRight = right.Split(new char[] { '|' }, StringSplitOptions.RemoveEmptyEntries);
                    foreach (string symbol in symbolsInRight)
                    {
                        productions.Add(left + '->' + symbol);
                        foreach (char c in symbol)
                        {
                            if (!symbols.Contains(c.ToString()))
                            {
                                symbols.Add(c.ToString());
                            }
                        }
                    }
                }
            }

            // 构造初始状态
            string initialState = 'S`->.S';
            foreach (var prod in productions)
                initialState = initialState + ' ' + prod.ToString().Replace('>', '>.');
            states.Add('0');
            itemsets.Add(initialState);

            // 构造其他状态
            int index = 0;
            while (index < itemsets.Count)
            {
                string[] items = itemsets[index].Split(' ');
                Dictionary<string, List<string>> gotoDict = new Dictionary<string, List<string>>(); // 存储每个符号的GOTO结果
                foreach (var item in items)
                {
                    int dotIndex = item.IndexOf('.');
                    if (dotIndex == item.Length - 1) // 点在最后，无法移进
                        continue;
                    string symbol = item[dotIndex + 1].ToString();
                    string newItem = item.Substring(0, dotIndex + 1) + '.' + item.Substring(dotIndex + 2);
                    if (!gotoDict.ContainsKey(symbol))
                    {
                        gotoDict[symbol] = new List<string>();
                    }
                    gotoDict[symbol].Add(newItem);
                }
                foreach (var kvp in gotoDict)
                {
                    string symbol = kvp.Key;
                    List<string> newItems = kvp.Value;
                    string newState = '';
                    foreach (var newItem in newItems)
                    {
                        if (newState == '')
                            newState = newItem;
                        else
                            newState = newState + ' ' + newItem;
                    }
                    if (!itemsets.Contains(newState))
                    {
                        itemsets.Add(newState);
                        states.Add(itemsets.Count.ToString());
                    }
                }
                index++;
            }
        }

        // 其他代码...
    }
}