/// <summary>
/// 分析输入串
/// 若输入串能构成正确语法树，返回True，否则返回False
/// </summary>
/// <param name="TokenList">输入串</param>
/// <param name="Root">语法树根节点</param>
/// <returns>若输入串能构成正确语法树，返回True，否则返回False</returns>
public bool Analyse(List <Token> TokenList, out TINYNode Root, out Token ErrorToken)
{
if (TokenList.Count == 0)
{
throw new Exception("输入穿中不不包含任何token");
}
if (TokenList.Any(token => token.Type == TokenType.Error))
{
throw new Exception("请先处理词法分析中发现的错误");
}
Stack <NTVTType> NTVTStack = new Stack <NTVTType>();
Stack <TINYNode> NodeStack = new Stack <TINYNode>();
NTVTStack.Push(toNTVT(Start));
Root = new TINYNode(Start.ToString());
ErrorToken = null;
NodeStack.Push(Root);
int index = 0;
NTVTType X; //栈顶元素
TINYNode curNode; //栈顶节点
VTType a; //当前输入
while (NTVTStack.Count != 0)
{
X = NTVTStack.Peek(); //栈顶元素
curNode = NodeStack.Peek(); //栈顶节点
if (index < TokenList.Count)
{
a = toVT(TokenList[index].Type.ToString());
}
else
{
a = VTType.θ;
}
if (X.ToString() == a.ToString()) //当前元素等于栈顶元素
{
NTVTStack.Pop();
NodeStack.Pop();
index++;
}
else if (isNT(X)) //当前元素不等于栈顶元素X，但是栈顶元素X是非终结符
{
LL1Item L = find(toNT(X), a);
if (L == null) //没有找到[X,a]
{
if (existX(toNT(X))) //X可以归结为ε
{
curNode.Children.Add(new TINYNode("ε"));
NTVTStack.Pop();
NodeStack.Pop();
}
else
{
curNode.Children.Add(new TINYNode(string.Format("Error")));
ErrorToken = TokenList[index];
return(false);
}
}
else //L!=null
{
NTVTStack.Pop();
NodeStack.Pop();
if (L.Rule.Contains(NTVTType.ε)) // A -> ε
{
curNode.Children.Add(new TINYNode("ε"));
continue;
}
for (int i = L.Rule.Count - 1; i >= 0; i--)
{
NTVTStack.Push(L.Rule[i]);
TINYNode newNode = new TINYNode(L.Rule[i].ToString());
NodeStack.Push(newNode);
curNode.Children.Insert(0, newNode);
}
}
}
else
{
ErrorToken = TokenList[index];
return(false);
}
}
//#if DEBUG
// Root.Show(1);
//#endif
return(true);
}
private void makeLL1List()
{
LL1ItemList = new List <LL1Item>();
foreach (var rule in TINYRules)
{
if (rule.Words.Contains(NTVTType.ε)) //规则包含ε,即 A -> ε
{
foreach (var word in followSet[rule.Start])
{
LL1Item cell = new LL1Item();
cell.NT = rule.Start;
cell.meet = word;
cell.Rule.AddRange(rule.Words);
LL1ItemList.Add(cell);
}
}
else if (isNT(rule.Words[0])) // A -> BC
{
foreach (var word in firstSet[toNT(rule.Words[0])].Where(v => v != VTType.ε))
{
LL1Item cell = new LL1Item();
cell.NT = rule.Start;
cell.meet = word;
cell.Rule.AddRange(rule.Words);
LL1ItemList.Add(cell);
}
if (firstSet[toNT(rule.Words[0])].Contains(VTType.ε))
{
foreach (var word in followSet[rule.Start])
{
LL1Item cell = new LL1Item();
cell.NT = rule.Start;
cell.meet = word;
cell.Rule.AddRange(rule.Words);
LL1ItemList.Add(cell);
}
}
}
else // A -> bC
{
LL1Item cell = new LL1Item();
cell.NT = rule.Start;
cell.meet = toVT(rule.Words[0]);
cell.Rule.AddRange(rule.Words);
LL1ItemList.Add(cell);
}
}
//#if DEBUG
// Debug.WriteLine("-----------------以下展示LL1List------------------------");
// Debug.WriteLine("LL1List共有{0}条记录", LL1ItemList.Count);
// foreach (var item in LL1ItemList)
// {
// Debug.Write(string.Format("[{0},{1}] -> ", item.NT.ToString(), item.meet.ToString()));
// foreach (var subitem in item.Rule)
// {
// Debug.Write(subitem);
// Debug.Write(" ");
// }
// Debug.Write(Environment.NewLine);
// }
// Debug.WriteLine("-----------------结束展示LL1List------------------------");
//#endif
}