private List productions = new List(); // 存储文法产生式
private List symbols = new List(); // 存储文法符号
private List states = new List(); // 存储状态
private List itemsets = new List(); // 存储项目族
private Dictionary<string, List> gotoTable = new Dictionary<string, List>(); // 存储GOTO表
private Dictionary<string, List> actionTable = new Dictionary<string, List>(); // 存储ACTION表
private void button2_Click(object sender, EventArgs e)//判别LR0文法
{
// 读取文法产生式
string[] productionsArr = richTextBox1.Text.Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
productions.AddRange(productionsArr);
// 获取文法符号
foreach (string production in productions)
{
string[] parts = production.Split(' ');
foreach (string part in parts)
{
if (!symbols.Contains(part))
{
symbols.Add(part);
}
}
}
// 初始化状态0
string state0 = "S' -> .S";
itemsets.Add(state0);
states.Add(GetState(itemsets));
BuilditemFamily();
}
private void BuilditemFamily()
{
bool changed = true;
while (changed)
{
changed = false;
for (int i = 0; i < itemsets.Count; i++)
{
List items = itemsets[i].Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries).ToList();
foreach (string symbol in symbols)
{
List newItems = new List();
foreach (string item in items)
{
string[] parts = item.Split(' ');
int dotIndex = Array.IndexOf(parts, ".");
if (dotIndex != -1 && dotIndex < parts.Length - 1 && parts[dotIndex + 1] == symbol)
{
string newItem = item.Replace(". ' + symbol, symbol + ' .");
if (!newItems.Contains(newItem))
{
newItems.Add(newItem);
}
}
}
if (newItems.Count > 0)
{
string newState = GetState(newItems);
if (!states.Contains(newState))
{
states.Add(newState);
itemsets.Add(newState);
changed = true;
}
int index = states.IndexOf(newState);
if (!gotoTable.ContainsKey(i + "," + symbol))
{
gotoTable.Add(i + "," + symbol, new List());
}
if (!gotoTable[i + "," + symbol].Contains(index.ToString()))
{
gotoTable[i + "," + symbol].Add(index.ToString());
}
}
}
}
}
}
