public static void resetAllVariebles()
{
//实例化全局XFA对象
globalNFA = new NFA();
globalDFA = new DFA();
globalMFA = new MFA();
}
//计算 a* 的NFA
public static NFA NFAofA_Clouse(NFA A)
{
NFA newNFA = new NFA();
List <String> startState = new List <String>();
List <String> endState = new List <String>();
List <String> inputChar = new List <String>();
List <transformFunction> TF = new List <transformFunction>();
inputChar = A.NFA_INPUT.ToList();//输入符号与输入的NFA A相同
startState.Add(stateID.ToString());
stateID++;
endState.Add(stateID.ToString());
stateID++;
TF = A.NFA_Transform.ToList();//保留原NFA A的转换函数
//在原NFA A的转换函数基础上添加转换函数
TF.Add(new transformFunction(startState[0], "$", endState[0]));
TF.Add(new transformFunction(startState[0], "$", A.NFA_START[0]));
TF.Add(new transformFunction(A.NFA_END[0], "$", A.NFA_START[0]));
TF.Add(new transformFunction(A.NFA_END[0], "$", endState[0]));
//更新NFA
newNFA.NFA_START = startState.ToArray();
newNFA.NFA_END = endState.ToArray();
newNFA.NFA_INPUT = inputChar.ToArray();
newNFA.NFA_Transform = TF.ToArray();
return(newNFA);
}
//正规式转NFA
//测试样例：r=(a|b)*(aa|bb)(a|b)*
public static NFA REtoNFA(String Expression)
{
int i = 0;
stateID = 0;//初始化stateID为0
Expression = addJoinOperator(Expression.Trim());
Expression = postfixExpression(Expression);
//Expression = "aa|*aa+b|b++ab|*+";
//MessageBox.Show("生成的后缀表达式：\n"+Expression);
Stack <NFA> NFAStack = new Stack <NFA>();
NFA A = null, B = null;//用于临时保存NFA
while (i < Expression.Length)
{
char currentChar = Expression[i];
//如果当前字符为字母，则构造该字母的NFA，并将其入NFA栈
if (isLetter(currentChar))
{
NFAStack.Push(NFAofA(currentChar));
}
else
{
switch (currentChar)
{
case '*':
A = NFAStack.Peek();
//MessageBox.Show(A.NFAInfo());
NFAStack.Pop();
NFAStack.Push(NFAofA_Clouse(A));
break;
case '|':
B = NFAStack.Peek();
//MessageBox.Show(B.NFAInfo());
NFAStack.Pop();
A = NFAStack.Peek();
//MessageBox.Show(A.NFAInfo());
NFAStack.Pop();
NFAStack.Push(NFAofA_Union_B(A, B));
break;
case '+':
B = NFAStack.Peek();
//MessageBox.Show(B.NFAInfo());
NFAStack.Pop();
A = NFAStack.Peek();
//MessageBox.Show(A.NFAInfo());
NFAStack.Pop();
NFAStack.Push(NFAofA_Join_B(A, B));
break;
default: break;
}
}
i++;
}
//栈顶NFA即为构造的最终NFA
return(NFAStack.Peek());
}
//NFA运算测试（返回NFA信息）
public static String NFATest()
{
stateID = 0;
NFA A = NFAofA('a');
NFA B = NFAofA('b');
//NFA C = NFAofA_Union_B(A,B);
NFA C = NFAofA_Join_B(A, B);
return(C.NFAInfo());
}
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
mainForm mForm = new mainForm();
mForm.StartPosition = FormStartPosition.CenterScreen;
//实例化全局XFA对象
globalNFA = new NFA();
globalDFA = new DFA();
globalMFA = new MFA();
Application.Run(mForm);
}
//函数功能：将正规式r(RegularExpression)转化为等价的NFA
private void REtoNFA()
{
//去除输入的空格
String Expression = editBox.Text.Replace(" ", "");
if (isRegularExpression(Expression) != null)
{
MessageBox.Show("正规式非法，请检查后重新输入！", "提示");
return;
}
if (Expression == "")
{
MessageBox.Show("无法生成NFA，请先输入正规式", "提示");
return;
}
NFA myNFA = REtoNFA_Helper.REtoNFA(Expression);
//MessageBox.Show(myNFA.NFAInfo());
//赋值Program.cs相关变量
Program.globalNFA.NFA_INPUT = myNFA.NFA_INPUT;
Program.globalNFA.NFA_START = myNFA.NFA_START;
Program.globalNFA.NFA_END = myNFA.NFA_END;
Program.globalNFA.NFA_Transform = myNFA.NFA_Transform;
//NFA转化函数显示
listViewNFA.Items.Clear();//清除当前项目
foreach (transformFunction TFItem in myNFA.NFA_Transform)
{
ListViewItem item = new ListViewItem();
item.Text = TFItem.from;
item.SubItems.Add(TFItem.by);
item.SubItems.Add(TFItem.to);
listViewNFA.Items.Add(item);
}
//显示初态集
String startState = "";
foreach (String item in myNFA.NFA_START)
{
startState = startState + item + ";";
}
textBoxNFAStart.Text = startState;
//显示终态集
String endState = "";
foreach (String item in myNFA.NFA_END)
{
endState = endState + item + ";";
}
textBoxNFAEnd.Text = endState;
}
//计算 a 的NFA
public static NFA NFAofA(char a)
{
NFA newNFA = new NFA();
List <String> startState = new List <String>();
List <String> endState = new List <String>();
List <String> inputChar = new List <String>();
List <transformFunction> TF = new List <transformFunction>();
inputChar.Add(a.ToString());
startState.Add(stateID.ToString());
stateID++;
endState.Add(stateID.ToString());
stateID++;
TF.Add(new transformFunction(startState[0], a.ToString(), endState[0]));
//更新NFA
newNFA.NFA_START = startState.ToArray();
newNFA.NFA_END = endState.ToArray();
newNFA.NFA_INPUT = inputChar.ToArray();
newNFA.NFA_Transform = TF.ToArray();
return(newNFA);
}
//计算 a|b 的NFA
public static NFA NFAofA_Union_B(NFA A, NFA B)
{
NFA newNFA = new NFA();
List <String> startState = new List <String>();
List <String> endState = new List <String>();
List <String> inputChar = new List <String>();
List <transformFunction> TF = new List <transformFunction>();
inputChar = A.NFA_INPUT.ToList();//先把A的输入符号加入新的NFA输入符号集合
foreach (String item in B.NFA_INPUT)
{
if (!inputChar.Contains(item)) //若B的输入符号不在A中，则加入新的NFA输入符号集合
{
inputChar.Add(item);
}
}
startState.Add(stateID.ToString());
stateID++;
endState.Add(stateID.ToString());
stateID++;
TF = A.NFA_Transform.ToList();//先把A的转换函数加入新的NFA转换函数集合
foreach (transformFunction item in B.NFA_Transform)
{
if (!TF.Contains(item)) //若B的转换函数不在A中，则加入新的NFA转换函数集合
{
TF.Add(item);
}
}
//在原NFA A的转换函数基础上添加转换函数
TF.Add(new transformFunction(startState[0], "$", A.NFA_START[0]));
TF.Add(new transformFunction(startState[0], "$", B.NFA_START[0]));
TF.Add(new transformFunction(A.NFA_END[0], "$", endState[0]));
TF.Add(new transformFunction(B.NFA_END[0], "$", endState[0]));
//更新NFA
newNFA.NFA_START = startState.ToArray();
newNFA.NFA_END = endState.ToArray();
newNFA.NFA_INPUT = inputChar.ToArray();
newNFA.NFA_Transform = TF.ToArray();
return(newNFA);
}
