SLR 分析表构造代码详解

class SLR { //产生式结点类 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 Container = new List(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;
    }
}

//分析表 结点
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;
    }
}

//分析句子
public class Analyze
{
    public List<string> stack_state = new List<string>(100);//记录状态栈
    public List<string> stack_symbol = new List<string>(100);//记录符号栈
    public List<string> Input_str = new List<string>(100);//记录输入串
    public List<string> Tran_pro = new List<string>(100);//记录所用产生式
}

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

Dictionary<char, HashSet<char>> follow = new Dictionary<char, HashSet<char>>();//非终结符的Follow集

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

//分析表 public void LRAnaly() { Table tnode = new Table();

    LRAna = new Table[proitemset.Count][];
    for (int i = 0; i < proitemset.Count; i++)
        LRAna[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 
            LRAna[i][j] = tnode;

    tnode = new Table('A', 0);
    LRAna[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

    for (int i = 0; i < Gy_itemset.Count; i++)
    {
        tnode = new Table('r', Find_pro(LRobjNum[proitemset[Gy_itemset[i]].Container[0]]));//归约项目 找到原产生式序号 添加状态r
        for (int j = 0; j < Echar.Count; j++)
        {
            LRAna[Gy_itemset[i]][j] = tnode;
        }
    }

    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);
            tnode = new Table('N', dfa[i].to);
            LRAna[dfa[i].from][CID + Echar.Count] = tnode;
        }
        else //不是归约项目 添加状态S
        {
            int CID = FindID(Echar, dfa[i].symbol);
            tnode = new Table('S', dfa[i].to);
            LRAna[dfa[i].from][CID] = tnode;
        }

    }
}

//SLR分析表 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 + 1];//加入一个$符号

for (int i = 0; i < proitemset.Count; i++)//初始化 赋予ERROR属性
    for (int j = 0; j < Echar.Count + 1; j++)//为终结符加r状态 
        SLRAna[i][j] = tnode;

tnode = new Table('A', 0);
SLRAna[1][Echar.Count] = 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

for (int i = 0; i < Gy_itemset.Count; i++)
{
    HashSet<char> Gy_follow = new HashSet<char>();//计算归约项目的Follow集
    char Gy_left = SLRproNum[SLRobjNum[proitemset[Gy_itemset[i]].Container[0]].Left[0]].Left[0];
    if (Gy_left == 'S')//如果是起始符号
        Gy_follow.Add('$');//将$加入Follow集
    if (follow.ContainsKey(Gy_left))
        Gy_follow.UnionWith(follow[Gy_left]);//将Follow集加入

    foreach (char c in Gy_follow)//为归约项目的Follow集中每个符号添加状态r
    {
        int CID = FindID(Echar, c);
        tnode = new Table('r', Find_pro(LRobjNum[proitemset[Gy_itemset[i]].Container[0]]));
        SLRAna[Gy_itemset[i]][CID] = tnode;
    }
}

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);
        tnode = new Table('N', dfa[i].to);
        SLRAna[dfa[i].from][CID] = tnode;
    }
    else //不是归约项目 添加状态S
    {
        int CID = FindID(Echar, dfa[i].symbol);
        tnode = new Table('S', dfa[i].to);
        SLRAna[dfa[i].from][CID] = tnode;
    }
}

}