/// <summary>
/// Traverses all left fields of the <see cref="RegExp"/>.
/// </summary>
/// <param name="right">The initial right part of the <see cref="RegExp"/>.</param>
/// <returns>Returns the final string of everyting right of the original.</returns>
private string TraverseRight(RegExp right)
{
string leftPart = "";
string rightPart = "";
char operatorAsChar = '$';
if (right.LeftRegExp != null)
{
leftPart = TraverseLeft(right.LeftRegExp);
}
if (right.op != Operator.ONE)
{
operatorAsChar = EnumToChar(right.op);
}
if (right.RightRegExp != null)
{
rightPart = TraverseRight(right.RightRegExp);
}
string rightString = right.terminals;
if (operatorAsChar != '$')
{
rightString = rightString + operatorAsChar;
}
if (leftPart != string.Empty)
{
if (operatorAsChar != '|')
{
rightString = "(" + leftPart + ")" + rightString;
}
else
{
rightString = leftPart + rightString;
}
}
if (rightPart != string.Empty)
{
if (operatorAsChar != '|')
{
rightString = rightString + "(" + rightPart + ")";
}
else
{
rightString = rightString + rightPart;
}
}
return(rightString);
}
private static void TestRegExAndThompson()
{
RegExpTest ret = new RegExpTest();
ret.testLanguage();
ret.testToString();
RegExp regExp1 = new RegExp("baa");
RegExp regExp2 = new RegExp("aba");
RegExp regExp3 = new RegExp("bb");
RegExp oneOrTwo = regExp1.Or(regExp2);
RegExp orStar = oneOrTwo.Star();
RegExp orStarDotThree = orStar.Dot(regExp3);
RegExp orStarDotThreePlus = orStarDotThree.Plus();
Console.WriteLine("-----------------------------------------");
Console.WriteLine("And conversion by use of the thompson construction:");
Console.WriteLine("-----------------------------------------");
ThompsonConstruction thompson = new ThompsonConstruction();
Automata <string> thompsonNDFA = thompson.GenerateNDFA(orStarDotThreePlus);
Console.WriteLine("thompsonNDFA is dfa? " + thompsonNDFA.IsDfa());
Console.WriteLine("-----------------------------------------");
thompsonNDFA.PrintTransitions();
Console.WriteLine("-----------------------------------------");
foreach (string state in thompsonNDFA.StartStates)
{
Console.WriteLine(state);
}
Console.WriteLine("-----------------------------------------");
foreach (string state in thompsonNDFA.FinalStates)
{
Console.WriteLine(state);
}
Console.WriteLine("-----------------------------------------");
Console.WriteLine("String {0} is a {1} string for Auto3.", THOMPSON_TEST_1, thompsonNDFA.IsStringAcceptable(THOMPSON_TEST_1) ? "valid" : "invalid");
Console.WriteLine("String {0} is a {1} string for Auto3.", THOMPSON_TEST_2, thompsonNDFA.IsStringAcceptable(THOMPSON_TEST_2) ? "valid" : "invalid");
Console.WriteLine("String {0} is a {1} string for Auto3.", THOMPSON_TEST_3, thompsonNDFA.IsStringAcceptable(THOMPSON_TEST_3) ? "valid" : "invalid");
Console.WriteLine("-----------------------------------------");
}
public RegExpTest()
{
a = new RegExp("a");
b = new RegExp("b");
// expr1: "baa"
expr1 = new RegExp("baa");
// expr2: "bb"
expr2 = new RegExp("bb");
// expr3: "baa | baa"
expr3 = expr1.Or(expr2);
// all: "(a|b)*"
all = (a.Or(b)).Star();
// expr4: "(baa | baa)+"
expr4 = expr3.Plus();
// expr5: "(baa | baa)+ (a|b)*"
expr5 = expr4.Dot(all);
}
