SLR 语法分析表构建算法及代码实现

public class SLRNode
{
    public string Left;
    public string Right;
    public SLRNode(string Left, string Right)
    {
        this.Left = Left;
        this.Right = Right;
    }
}

//项目集类
public class SLRitemsets
{
    public List<int> Container
        = new List<int>(100);
    //记录项目在项目集合中的序号
}

//DFA结点
public struct DFA
{
    public int from;
    public char symbol;
    public int to;
    public DFA(int from, char symbol, int to)
    {
        this.from = from;
        this.symbol = symbol;
        this.to = to;
    }
}

public class Table
{
    public bool error;//是否为ERROR
    public char type;//结点类型
    public int id;//数值
    public Table()
    {
        this.error = true;
    }
    public Table(char type, int id)
    {
        this.type = type;
        this.id = id;
        this.error = false;
    }
}

public class SLRParser
{
    public DFA[] dfa = new DFA[100];
    public int Pindex = 0; //dfa数组指针
    public Table[][] SLRAna;//分析表
    public Analyze Jz;
    public bool Success = false;
    public List<SLRNode> SLRproNum = new List<SLRNode>(50);//产生式 列表
    public List<SLRNode> SLRobjNum = new List<SLRNode>(50);//项目 列表
    public List<SLRitemsets> proitemset = new List<SLRitemsets>(100);//项目集合
    public List<int> Gy_obj = new List<int>(50);//归约项目序号集合
    public List<int> Gy_itemset = new List<int>(50);//含有归约项目的集合的序号 的集合
    public List<char> Nchar = new List<char>(50);//非终结符集合
    public List<char> Echar = new List<char>(50);//终结符集合

    public List<char>[] Follow; //每个非终结符的follow集合

    public string RStr = '';
    public string RStr_obitemset = '';//输出返回
    public string RStr_DFA = '';
    public string RStr_ANA = '';

    public Table[][] GET_ANA()
    {
        SLRAnaly();
        RStr_ANA += '\r\nSLR0分析表:\r\n    ';
        int i;
        for (i = 0; i < Echar.Count; i++)
        {
            RStr_ANA += Echar[i].ToString() + '     ';
        }
        for (i = 0; i < Nchar.Count; i++)
        {
            RStr_ANA += Nchar[i].ToString() + '     ';
        }
        RStr_ANA += '\r\n';
        for (i = 0; i < proitemset.Count; i++)
        {
            RStr_ANA += i.ToString() + '  ';
            for (int j = 0; j < Echar.Count + Nchar.Count; j++)
            {

                if (SLRAna[i][j].error)
                {
                    RStr_ANA += '  ' + '    ';
                }
                else if (i == 1 && j == Echar.Count - 1)
                {
                    RStr_ANA += 'AC' + '    ';
                }
                else if (SLRAna[i][j].type != 'N')
                {
                    RStr_ANA += SLRAna[i][j].type.ToString() + SLRAna[i][j].id.ToString() + '    ';
                }
                else
                    RStr_ANA += SLRAna[i][j].id.ToString() + '    ';
            }
            RStr_ANA += '\r\n';
        }

        return SLRAna;

    }

    public void SLRAnaly()
    {
        Table tnode = new Table();

        SLRAna = new Table[proitemset.Count][];
        for (int i = 0; i < proitemset.Count; i++)
            SLRAna[i] = new Table[Echar.Count + Nchar.Count];

        for (int i = 0; i < proitemset.Count; i++)//初始化 赋予ERROR属性
            for (int j = 0; j < Echar.Count + Nchar.Count; j++)//为终结符加r状态 
                SLRAna[i][j] = tnode;

        tnode = new Table('A', 0);
        SLRAna[1][FindID(Echar, '#')] = tnode;//项目集1必定是接受项目   构建[1][#]:acc的情况 先直接赋值好 dfa里没有

        bool[] visited = new bool[proitemset.Count]; //记录状态是否已经被添加过

        for (int i = 0; i < Gy_itemset.Count; i++)
        {
            SLRNode item = SLRobjNum[proitemset[Gy_itemset[i]].Container[0]];
            char left = item.Left[0];
            List<char> follow = GetFollow(left);
            foreach (char c in follow)
            {
                int CID = FindID(Echar, c);
                if (!visited[Gy_itemset[i]]) //如果状态未被添加过，则添加r状态
                {
                    SLRAna[Gy_itemset[i]][CID] = new Table('r', Find_pro(item));
                    if (c == '#')
                    {
                        foreach (char e in Echar)
                        {
                            int EID = FindID(Echar, e);
                            SLRAna[Gy_itemset[i]][EID] = new Table('r', Find_pro(item));
                        }
                    }
                    visited[Gy_itemset[i]] = true; //标记状态已被添加
                }
            }
        }

        visited = new bool[Pindex]; //重置visited数组

        for (int i = 0; i < Pindex; i++)
        {
            if (isFinalsymbol(dfa[i].symbol))//symbol为非终结符  添加状态N
            {
                int CID = FindID(Nchar, dfa[i].symbol);
                if (!visited[dfa[i].from]) //如果状态未被添加过，则添加N状态
                {
                    SLRAna[dfa[i].from][CID + Echar.Count] = new Table('N', dfa[i].to);
                    visited[dfa[i].from] = true; //标记状态已被添加
                }
            }
            else //不是归约项目 添加状态S
            {
                int CID = FindID(Echar, dfa[i].symbol);
                if (!visited[dfa[i].from]) //如果状态未被添加过，则添加S状态
                {
                    SLRAna[dfa[i].from][CID] = new Table('S', dfa[i].to);
                    visited[dfa[i].from] = true; //标记状态已被添加
                }
            }
        }
    }

    public List<char> GetFollow(char c)
    {
        List<char> follow = new List<char>();
        if (c == 'E')
            follow.Add('#');
        foreach (SLRNode node in SLRproNum)
        {
            int index = node.Right.IndexOf(c);
            if (index != -1 && index < node.Right.Length - 1)
            {
                char next = node.Right[index + 1];
                if (isFinalsymbol(next))
                    follow.Add(next);
                else
                {
                    List<char> first = GetFirst(next);
                    if (first.Contains('#'))
                    {
                        first.Remove('#');
                        follow.AddRange(first);
                        if (node.Left[0] != c) //避免死循环
                            follow.AddRange(GetFollow(node.Left[0]));
                    }
                    else
                    {
                        follow.AddRange(first);
                    }
                }
            }
            else if (index != -1 && index == node.Right.Length - 1 && node.Left[0] != c) //避免死循环
            {
                follow.AddRange(GetFollow(node.Left[0]));
            }
        }
        follow = follow.Distinct().ToList();
        return follow;
    }


    public List<char> GetFirst(char c)
    {
        List<char> first = new List<char>();
        if (isFinalsymbol(c))
            first.Add(c);
        else
        {
            foreach (SLRNode node in SLRproNum)
            {
                if (node.Left[0] == c)
                {
                    if (node.Right[0] == c)
                        continue;
                    else if (isFinalsymbol(node.Right[0]))
                        first.Add(node.Right[0]);
                    else
                    {
                        List<char> subFirst = GetFirst(node.Right[0]);
                        if (subFirst.Contains('#'))
                        {
                            subFirst.Remove('#');
                            first.AddRange(subFirst);
                            if (node.Right.Length > 1)
                            {
                                List<char> nextFirst = GetFirst(node.Right[1]);
                                first.AddRange(nextFirst);
                            }
                            else
                            {
                                first.AddRange(GetFollow(node.Left[0]));
                            }
                        }
                        else
                        {
                            first.AddRange(subFirst);
                        }
                    }
                }
            }
        }
        first = first.Distinct().ToList();
        return first;
    }

    // ... 其他函数和成员变量 ...
}