SLR 分析表构建算法实现 - C# 代码示例

{ "title": "SLR 分析表构建算法实现 - C# 代码示例", "description": "本文介绍了使用 C# 语言实现 SLR 分析表构建算法的代码示例，包括类定义、算法实现和相关函数的调用。", "keywords": "SLR 分析表, LR(0) 分析表, 编译原理, 形式语言, C#", "content": "```c# using System; using System.Collections.Generic; using System.Linq;

public 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;
    }
}

public DFA[] dfa = new DFA[100];
public Table[][] SLRAna;//分析表

public void SLRAnaly()
{
    //获取LR(0)分析表
    buildtable();

    //初始化SLR分析表
    SLRAna = new Table[states.Count][];
    for (int i = 0; i < states.Count; i++)
    {
        SLRAna[i] = new Table[terminals.Count + nonterminal.Count];
        for (int j = 0; j < terminals.Count + nonterminal.Count; j++)
        {
            SLRAna[i][j] = new Table();
        }
    }

    //填充移进项和归约项
    for (int i = 0; i < states.Count; i++)
    {
        for (int j = 0; j < terminals.Count; j++)
        {
            if (table[i][j] != "")
            {
                if (table[i][j][0] == 'S')
                {
                    int nextstate = int.Parse(table[i][j].Substring(1));
                    SLRAna[i][j].type = 's';
                    SLRAna[i][j].id = nextstate;
                }
                else if (table[i][j][0] == 'r')
                {
                    int productionIndex = int.Parse(table[i][j].Substring(1));
                    List<string> productionRHS = productions[production.Keys.ToList()[productionIndex - 1]][0];
                    string productionLHS = production.Keys.ToList()[productionIndex - 1];
                    int reduceState = -1;
                    for (int k = 0; k < states.Count; k++)
                    {
                        if (states[k].items.Any(item => item.LHS == productionLHS && item.RHS.SequenceEqual(productionRHS)))
                        {
                            reduceState = k;
                            break;
                        }
                    }
                    SLRAna[i][j].type = 'r';
                    SLRAna[i][j].id = reduceState;
                }
            }
        }
    }

    //填充goto项
    for (int i = 0; i < states.Count; i++)
    {
        for (int j = 0; j < nonterminal.Count; j++)
        {
            int nextState = -1;
            if (transitions.ContainsKey(i))
            {
                foreach (var item in transitions[i])
                {
                    if (item[0].ToString().Equals(nonterminal[j]))
                    {
                        nextState = int.Parse(item.Substring(1));
                        break;
                    }
                }
            }
            if (nextState != -1)
            {
                SLRAna[i][terminals.Count + j].type = 'g';
                SLRAna[i][terminals.Count + j].id = nextState;
            }
        }
    }
}

//以下为LR(0)分析表的构建代码
//省略...

}