以下是一个简单的LR0文法分析器的示例代码:

using System;
using System.Collections.Generic;

class LR0Parser
{
    private List<string> productions; // 产生式列表
    private Dictionary<string, HashSet<string>> firstSets; // First集合
    private Dictionary<string, HashSet<string>> followSets; // Follow集合
    private Dictionary<string, Dictionary<string, int>> actionTable; // Action表
    private Dictionary<string, Dictionary<string, int>> gotoTable; // Goto表

    public LR0Parser(List<string> productions)
    {
        this.productions = productions;
        this.firstSets = new Dictionary<string, HashSet<string>>();
        this.followSets = new Dictionary<string, HashSet<string>>();
        this.actionTable = new Dictionary<string, Dictionary<string, int>>();
        this.gotoTable = new Dictionary<string, Dictionary<string, int>>();
        ComputeFirstSets();
        ComputeFollowSets();
        ComputeActionTable();
        ComputeGotoTable();
    }

    // 计算First集合
    private void ComputeFirstSets()
    {
        // TODO: 实现计算First集合的算法
    }

    // 计算Follow集合
    private void ComputeFollowSets()
    {
        // TODO: 实现计算Follow集合的算法
    }

    // 计算Action表
    private void ComputeActionTable()
    {
        // TODO: 实现计算Action表的算法
    }

    // 计算Goto表
    private void ComputeGotoTable()
    {
        // TODO: 实现计算Goto表的算法
    }

    // 解析输入串
    public bool Parse(string input)
    {
        Stack<int> stateStack = new Stack<int>();
        Stack<string> symbolStack = new Stack<string>();
        stateStack.Push(0);
        int i = 0;
        while (i < input.Length)
        {
            int state = stateStack.Peek();
            string symbol = input[i].ToString();
            if (actionTable.ContainsKey(state.ToString()) && actionTable[state.ToString()].ContainsKey(symbol))
            {
                int action = actionTable[state.ToString()][symbol];
                if (action > 0)
                {
                    stateStack.Push(action);
                    symbolStack.Push(symbol);
                    i++;
                }
                else if (action < 0)
                {
                    int productionIndex = -action - 1;
                    string production = productions[productionIndex];
                    string[] parts = production.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
                    for (int j = 0; j < parts.Length - 1; j++)
                    {
                        stateStack.Pop();
                        symbolStack.Pop();
                    }
                    int newState = gotoTable[stateStack.Peek().ToString()][parts[0]];
                    stateStack.Push(newState);
                    symbolStack.Push(parts[0]);
                }
                else
                {
                    return true;
                }
            }
            else
            {
                return false;
            }
        }
        return false;
    }
}

class Program
{
    static void Main(string[] args)
    {
        List<string> productions = new List<string>();
        productions.Add("S -> E");
        productions.Add("E -> E + T");
        productions.Add("E -> T");
        productions.Add("T -> T * F");
        productions.Add("T -> F");
        productions.Add("F -> ( E )");
        productions.Add("F -> id");
        LR0Parser parser = new LR0Parser(productions);
        Console.WriteLine(parser.Parse("id + id * id"));
    }
}

以上代码仅提供了一个框架,需要根据具体的LR0文法分析算法来实现计算First集合、Follow集合、Action表和Goto表的方法。同时,需要根据具体的文法来修改产生式列表

如何使用C#语言实现LR0文法分析器请给出示例代码

原文地址: https://www.cveoy.top/t/topic/hdGX 著作权归作者所有。请勿转载和采集!

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