private static void LoadFile(string fileName)
{
Console.WriteLine("Loading from file: {0}", fileName);
if (!System.IO.File.Exists(fileName))
{
Console.WriteLine("No such file!");
}
var eNfa = AutomataBuilder.FromFile(fileName);
Console.WriteLine("Loaded.");
Console.WriteLine("=== NFA Primitive Infomation ===");
Console.WriteLine(eNfa.About());
Console.WriteLine("Epsilon Closures: ");
foreach (var state in eNfa.States)
{
var eclosure = eNfa.GetEpsilonClosureOf(state);
Console.WriteLine("{0}: {{{1}}}", state, string.Join(',', eclosure));
}
Console.WriteLine("\nConverted.\n");
Console.WriteLine("=== DFA Infomation ===");
var dfa = AutomataConverter.EpsilonNfaToDFA(eNfa);
Console.WriteLine(dfa.About());
}
private static void Example3()
{
var eNfa = new AutomataBuilder()
.SetStates(new string[] { "p", "q", "r" })
.SetInputSymbols(new char[] { '0', '1', '$' })
.SetTransitionFunction(new string[] {
"f(p,0)=p",
"f(p,1)={p,q}",
"f(q,0)=r",
"f(q,1)=r",
})
.SetInitialState("p")
.SetFinalState("r")
.Build();
Console.WriteLine("=== NFA Primitive Infomation ===");
Console.WriteLine(eNfa.About());
Console.WriteLine("Epsilon Closures: ");
foreach (var state in eNfa.States)
{
var eclosure = eNfa.GetEpsilonClosureOf(state);
Console.WriteLine("{0}: {{{1}}}", state, string.Join(',', eclosure));
}
Console.WriteLine("\nConverted.\n");
Console.WriteLine("=== DFA Infomation ===");
var dfa = AutomataConverter.EpsilonNfaToDFA(eNfa);
Console.WriteLine(dfa.About());
}
private static void Example2()
{
var nfa = new AutomataBuilder()
.SetStates(new string[] { "q0", "q1", "q2" })
.SetInputSymbols(new char[] { 'a', 'b', '$' })
.SetTransitionFunction(new string[] {
"f(q0,a)=q1",
"f(q0,$)=q1",
"f(q1,a)=q0",
"f(q1,b)=q1",
"f(q1,a)=q2",
"f(q1,b)=q2",
"f(q2,a)=q2",
"f(q2,b)=q1",
"f(q2,b)=q1",
})
.SetInitialState("q0")
.SetFinalState("q1")
.Build();
Console.WriteLine("=== NFA Primitive Infomation ===");
Console.WriteLine(nfa.About());
Console.WriteLine("Epsilon Closures: ");
foreach (var state in nfa.States)
{
var eclosure = nfa.GetEpsilonClosureOf(state);
Console.WriteLine("{0}: {{{1}}}", state, string.Join(',', eclosure));
}
var transitionFunctions = new HashSet <TransitionFunction>();
foreach (var state in nfa.States)
{
var eclosure = nfa.GetEpsilonClosureOf(state);
foreach (var eclosureState in eclosure)
{
var acceptableInputs = nfa.GetAcceptableInputOf(eclosureState, true);
foreach (var input in acceptableInputs)
{
var func = (new TransitionFunction(eclosure, input, nfa.GetNextStatesOf(eclosure, input)));
transitionFunctions.Add(func);
}
}
}
Console.WriteLine("New transition functions:");
Console.WriteLine(string.Join("\n", transitionFunctions));
}
private static void Example1()
{
var nfa = new AutomataBuilder()
.SetStates(new string[] { "A", "B", "C", "D", "E" })
.SetInputSymbols(new char[] { '0', '1', '$' })
.SetTransitionFunction(new string[] {
"f(A,0)=B",
"f(A,$)=C",
"f(B,$)=D",
"f(C,$)=D",
"f(C,1)=E",
"f(D,0)=D",
"f(D,1)=E",
})
.SetInitialState("A")
.SetFinalState("E")
.Build();
Console.WriteLine("=== NFA Primitive Infomation ===");
Console.WriteLine(nfa.About());
Console.WriteLine("Epsilon Closures: ");
foreach (var state in nfa.States)
{
var eclosure = nfa.GetEpsilonClosureOf(state);
Console.WriteLine("{0}: {{{1}}}", state, string.Join(',', eclosure));
}
var transitionFunctions = new SortedSet <TransitionFunction>();
foreach (var state in nfa.States)
{
var eclosure = nfa.GetEpsilonClosureOf(state);
foreach (var eclosureState in eclosure)
{
var acceptableInputs = nfa.GetAcceptableInputOf(eclosureState, true);
foreach (var input in acceptableInputs)
{
var func = (new TransitionFunction(eclosure, input, nfa.GetNextStatesOf(eclosure, input)));
transitionFunctions.Add(func);
}
}
}
Console.WriteLine("New transition functions:");
Console.WriteLine(string.Join("\n", transitionFunctions));
}
/// <summary>
/// 将 NFA(可带空转) 转换为 DFA
/// </summary>
/// <param name="eNfa">NFA</param>
/// <returns></returns>
public static Automata EpsilonNfaToDFA(Automata eNfa)
{
// 首先将 eNFA 转换为 NFA
var nfaTransitionFunctions = RemoveEpsilonTransitions(eNfa);
Debug.WriteLine("New transition functions:");
Debug.WriteLine(string.Join("\n", nfaTransitionFunctions));
var dfa = new AutomataBuilder()
.SetInputSymbols(eNfa.InputSymbols.ToArray())
.Build();
// 获取初始转移函数
var initalTransitionFunction = TransitionFunction.GetInitalTransitionFunction(nfaTransitionFunctions, eNfa.InitialState);
if (0 == initalTransitionFunction.Count)
{
throw new Exception("Initial transition function not found!");
}
var dfaTransitionFunctions = NfaToDfaTransitionFunctions(nfaTransitionFunctions, dfa.InputSymbols, initalTransitionFunction);
var stateMap = TransitionFunction.MergeStates(dfaTransitionFunctions);
dfa.States = new SortedSet <State>();
foreach (var kv in stateMap)
{
dfa.States.Add(new State(kv.Value.Name, kv.Key));
}
SortedSet <State> finalStates = GetFinialStates(eNfa, dfa);
dfa.FinalStates = finalStates;
dfa.InitialState = stateMap[eNfa.InitialState.Name];
var mergedFunctions = TransitionFunction.MergeFunctions(dfaTransitionFunctions, stateMap);
dfa.TransitionFunctions = mergedFunctions;
Debug.WriteLine("DFA transition functions:");
Debug.WriteLine(string.Join("\n", dfaTransitionFunctions));
return(dfa);
}
public static Automata FromString(string input)
{
string pattern = @".*NFA(.*)where(.*)and(.*)by(.*)";
RegexOptions options = RegexOptions.Singleline;
Match m = Regex.Match(input, pattern, options);
// Console.WriteLine("'{0}' found at index {1}", m.Value, m.Index);
// Group 2: where ... and
var g2 = m.Groups[2];
var raw1 = g2.Value.Replace(" ", "").Replace("\t", "").Replace("\r", "").Replace("{", "").Replace("}", "");
var lines1 = raw1.Split('\n');
var dict = new Dictionary <string, string>();
foreach (var line in lines1)
{
if (line.Trim().Length == 0)
{
continue;
}
var kv = line.Split("=");
if (kv.Length != 2)
{
throw new Exception("Invalid line: " + line);
}
var k = kv[0].ToLower().Trim();
dict.Add(k, kv[1]);
}
foreach (var key in new string[] { "q", "t", "q0", "f" })
{
if (!dict.ContainsKey(key))
{
throw new Exception("Missing automata argument: " + key);
}
}
// Group 4: by ...
var g4 = m.Groups[4];
var raw2 = g4.Value.Replace(" ", "").Replace("\t", "").Replace("\r", "").Replace("{", "").Replace("}", "");
var lines2 = raw2.Split('\n');
var exps = new List <string>();
foreach (var line in lines2)
{
if (line.Trim().Length == 0)
{
continue;
}
exps.Add(line.Trim());
}
// build
var builder = new AutomataBuilder();
var automata = builder
.SetStates(dict["q"])
.SetInputSymbols(dict["t"])
.SetInitialState(dict["q0"])
.SetFinalState(dict["f"])
.SetTransitionFunction(exps.ToArray())
.Build();
return(automata);
}
