SLR1 分析表构建算法实现 - C# 代码示例

public Table[][] GET_ANA() { Table[][] ana = new Table[proitemset.Count][]; for (int i = 0; i < proitemset.Count; i++) { ana[i] = new Table[Echar.Count + Nchar.Count];//每个项目集都有Echar.Count + Nchar.Count个分析表结点 for (int j = 0; j < ana[i].Length; j++) { ana[i][j] = new Table(); }

    for (int j = 0; j < proitemset[i].Container.Count; j++)
    {
        int index = proitemset[i].Container[j];
        int point = SLRobjNum[index].Right.IndexOf('.');
        if (point == SLRobjNum[index].Right.Length - 1)//.在最后  归约项目
        {
            for (int k = 0; k < Echar.Count; k++)
            {
                int id = isexist(dfa, i, Echar[k]);
                if (id != -1)
                {
                    ana[i][k] = new Table('r', index);//归约
                }
            }
        }
        else
        {
            char next = SLRobjNum[index].Right[point + 1];
            if (isFinalsymbol(next))//终结符
            {
                int id = isexist(dfa, i, next);
                if (id != -1)
                {
                    ana[i][Echar.IndexOf(next)] = new Table('s', id);//移进
                }
            }
        }
    }

    for (int j = 0; j < Gy_obj.Count; j++)
    {
        int index = Gy_obj[j];
        for (int k = 0; k < Follow[Nchar.IndexOf(SLRobjNum[index].Left)].Count; k++)
        {
            char ch = Follow[Nchar.IndexOf(SLRobjNum[index].Left)][k];
            int id = isexist(dfa, i, ch);
            if (id != -1)
            {
                ana[i][Echar.Count + Nchar.IndexOf(ch)] = new Table('r', index);//归约
            }
        }
    }
}
return ana;

}

public void SLRAnaly() { Follow = new List[Nchar.Count]; for (int i = 0; i < Follow.Length; i++) { Follow[i] = new List(); } Follow[Nchar.IndexOf('S')].Add('#');//开始符号的follow集合中加入# for (int i = 0; i < proitemset.Count; i++) { for (int j = 0; j < proitemset[i].Container.Count; j++) { int index = proitemset[i].Container[j]; int point = SLRobjNum[index].Right.IndexOf('.'); if (point != SLRobjNum[index].Right.Length - 1)//.不在最后 { char next = SLRobjNum[index].Right[point + 1]; if (!isFinalsymbol(next))//非终结符 { List lr_club = new List(100);//记录项目的序号 lr_club.Add(index + 1); for (int k = j + 1; k < proitemset[i].Container.Count; k++) { int index2 = proitemset[i].Container[k]; if (SLRobjNum[index2].Left == SLRobjNum[index].Right.Substring(point + 1, 1)) { lr_club.Add(index2 + 1); } } lr_club = Closure(lr_club);//求闭包 int value = isexist(lr_club); if (value == -1) { SLRitemsets LR_C = new SLRitemsets(); LR_C.Container = lr_club; proitemset.Add(LR_C); } Follow[Nchar.IndexOf(SLRobjNum[index].Right.Substring(point + 1, 1))].AddRange(getFirst(lr_club)); } } } }

SLRAna = GET_ANA();
Jz = new Analyze();
Jz.stack_state.Add("0");
Jz.stack_symbol.Add("#");
Jz.Input_str.AddRange(inputStr);
while (Jz.Input_str.Count > 0)
{
    int state = int.Parse(Jz.stack_state[Jz.stack_state.Count - 1]);
    int symbolIndex = Echar.IndexOf(Jz.Input_str[0][0]);
    if (symbolIndex == -1)
    {
        symbolIndex = Echar.Count + Nchar.IndexOf(Jz.Input_str[0][0]);
    }
    if (SLRAna[state][symbolIndex].error)
    {
        Success = false;
        return;
    }
    else if (SLRAna[state][symbolIndex].type == 's')
    {
        Jz.stack_state.Add(SLRAna[state][symbolIndex].id.ToString());
        Jz.stack_symbol.Add(Jz.Input_str[0][0].ToString());
        Jz.Input_str.RemoveAt(0);
    }
    else if (SLRAna[state][symbolIndex].type == 'r')
    {
        int index = SLRAna[state][symbolIndex].id;
        string left = SLRobjNum[index].Left;
        string right = SLRobjNum[index].Right;
        for (int i = 0; i < right.Length; i++)
        {
            Jz.stack_state.RemoveAt(Jz.stack_state.Count - 1);
            Jz.stack_symbol.RemoveAt(Jz.stack_symbol.Count - 1);
        }
        int newState = int.Parse(Jz.stack_state[Jz.stack_state.Count - 1]);
        Jz.stack_symbol.Add(left);
        Jz.stack_state.Add(SLRAna[newState][Nchar.Count + Echar.IndexOf(left)].id.ToString());
        Jz.Tran_pro.Add(left + "->" + right);
    }
    else
    {
        Success = true;
        return;
    }
}
Success = true;

}