C#实现LL(1)文法判断及FIRST、FOLLOW集计算与可视化

// 判断文法是否为LL(1)文法
private void button4_Click(object sender, EventArgs e)
{
    string text = richTextBox1.Text;
    production = new Dictionary<string, List<string>>();
    string[] pro = text.Split('
');
    foreach (string s in pro)
    {
        if (s == '') continue;

        Regex.Replace(s, ' ', '');
        string[] ga = Regex.Split(s, '->');
        if (ga.Length != 2) return;
        if (ga[0].Length == 0 || ga[1].Length == 0)
            return;
        if (ga[0].Length != 1 || !char.IsUpper(ga[0][0])) return;

        string[] ga2 = Regex.Split(ga[1], '\|');
        if (!production.ContainsKey(ga[0]))
            production.Add(ga[0], new List<string>());
        foreach (string s1 in ga2)
            production[ga[0]].Add(s1);
    }

    firsts = new Dictionary<string, List<string>>();
    foreach (var item in production.Keys)
        GetFirst(item, production, firsts);

    follows = new Dictionary<string, List<string>>();
    foreach (var item in production.Keys)
        GetFollow(item, production, firsts, follows);

    if (JudgeLL1(production, firsts, follows))
    {
        MessageBox.Show('该文法是LL(1)文法\n');
        
    }
    else
    {
        MessageBox.Show('该文法不是LL(1)文法，存在左递归或者存在FIRST集合有交集的情况！\n');
    }
    button1.Enabled = true;
    button2.Enabled = true;
    button3.Enabled = true;
}

// 显示FIRST集
private void button1_Click(object sender, EventArgs e)
{
    listView1.Columns.Clear();
    listView1.Items.Clear();

    // 添加终结符
    listView1.Columns.Add('+', 50);
    listView1.Columns.Add('￥', 50);
    listView1.Columns.Add('*', 50);
    listView1.Columns.Add('(', 50);
    listView1.Columns.Add(')', 50);
    listView1.Columns.Add('i', 50);
    listView1.Columns.Add('#', 50);

    // 添加非终结符
    foreach (var item in production.Keys)
    {
        listView1.Items.Add(item);
    }

    // 填充表格
    foreach (var item in production.Keys)
    {
        ListViewItem listItem = listView1.FindItemWithText(item);
        List<string> firstList = firsts[item];
        foreach (string terminal in new[] { '+', '￥', '*', '(', ')', 'i', '#' })
        {
            listItem.SubItems.Add(firstList.Contains(terminal) ? '1' : '0');
        }
    }
}

// 显示FOLLOW集
private void button2_Click(object sender, EventArgs e)
{
    listView2.Columns.Clear();
    listView2.Items.Clear();

    // 添加终结符
    listView2.Columns.Add('+', 50);
    listView2.Columns.Add('￥', 50);
    listView2.Columns.Add('*', 50);
    listView2.Columns.Add('(', 50);
    listView2.Columns.Add(')', 50);
    listView2.Columns.Add('i', 50);
    listView2.Columns.Add('#', 50);

    // 添加非终结符
    foreach (var item in production.Keys)
    {
        listView2.Items.Add(item);
    }

    // 填充表格
    foreach (var item in production.Keys)
    {
        ListViewItem listItem = listView2.FindItemWithText(item);
        List<string> followList = follows[item];
        foreach (string terminal in new[] { '+', '￥', '*', '(', ')', 'i', '#' })
        {
            listItem.SubItems.Add(followList.Contains(terminal) ? '1' : '0');
        }
    }
}