public WordsInGrammarProblem Generate(int targetLevel)
{
ContextFreeGrammar grammar = null;
var inNeeded = 1;
var outNeeded = 1;
// We iterate until we get a CNF
grammar = GrammarGenerator.GenerateRandom();
while (GrammarUtilities.getEquivalentCNF(grammar) == null)
{
grammar = GrammarGenerator.GenerateRandom();
}
inNeeded = rnd.Next(1, 5);
outNeeded = rnd.Next(1, 5);
if (targetLevel == Generation.HIGH)
{
inNeeded = rnd.Next(3, 5);
outNeeded = rnd.Next(3, 5);
}
else if (targetLevel == Generation.MEDIUM)
{
inNeeded = rnd.Next(2, 4);
outNeeded = rnd.Next(2, 4);
}
else if (targetLevel == Generation.LOW)
{
inNeeded = rnd.Next(1, 4);
outNeeded = rnd.Next(1, 4);
}
return(new WordsInGrammarProblem(grammar, inNeeded, outNeeded));
}
Tuple <HashSet <Nonterminal>, List <Tuple <Production, int> > >[][] cykTable; //resulting CYK table
public CYKProblem(ContextFreeGrammar grammar, string word)
{
this.grammar = GrammarUtilities.getEquivalentCNF(grammar);
this.word = word;
this.cykTable = GrammarUtilities.cyk(grammar, word);
}
public void EqualityTest5() // (a|b)^n
{
String sg1 = "S -> a|b|aa|aS|bS|bbbbS";
String sg2 = "S->X|X S X->a|b";
ContextFreeGrammar g1 = GrammarParser <char> .Parse(f1, sg1);
ContextFreeGrammar g2 = GrammarParser <char> .Parse(f1, sg2);
var res = GrammarUtilities.findDifferenceWithTimelimit(g1, g2, true, 100);
Assert.IsTrue(res.Item2.Count == 0 && res.Item3.Count == 0);
}
public void EqualityTest4() // (a|b|c|d|e|f|g|h|i|j)*
{
String sg1 = "S->|a|b|c|d|e|f|g|h|i|j|S S";
String sg2 = "S->X|X S| X->a|b|c|d|e|f|g|h|i|j";
ContextFreeGrammar g1 = GrammarParser <char> .Parse(f1, sg1);
ContextFreeGrammar g2 = GrammarParser <char> .Parse(f1, sg2);
var res = GrammarUtilities.findDifferenceWithTimelimit(g1, g2, true, 50);
Assert.IsTrue(res.Item2.Count == 0 && res.Item3.Count == 0);
}
public void EqualityTest3() // a^n b^n
{
String sg1 = "S->aT T->aT U|b U->b";
String sg2 = "P->aR R->abb|aRb|b";
ContextFreeGrammar g1 = GrammarParser <char> .Parse(f1, sg1);
ContextFreeGrammar g2 = GrammarParser <char> .Parse(f1, sg2);
var res = GrammarUtilities.findDifferenceWithTimelimit(g1, g2, true, 100);
Assert.IsTrue(res.Item2.Count == 0 && res.Item3.Count == 0);
}
public void EqualityTest2()
{
String sg1 = "S->aSb|absjjfhghs|";
String sg2 = "S->aSb|aaSbb|";
ContextFreeGrammar g1 = GrammarParser <char> .Parse(f1, sg1);
ContextFreeGrammar g2 = GrammarParser <char> .Parse(f1, sg2);
var res = GrammarUtilities.findDifferenceWithTimelimit(g1, g2, true, 100);
Assert.IsTrue(res.Item2[0].Equals("absjjfhghs") && res.Item3.Count == 0);
}
public void prefixTest1() // balanced parenthesis
{
String sg1 = "S -> S S|(S)|";
ContextFreeGrammar g = GrammarParser <char> .Parse(f1, sg1);
g = GrammarUtilities.getEquivalentCNF(g);
Assert.AreEqual(-2, GrammarUtilities.longestPrefixLength(g, "()(())()()")); // full
Assert.AreEqual("()(())".Length, GrammarUtilities.longestPrefixLength(g, "()(()))()()"));
Assert.AreEqual("()(())((((".Length, GrammarUtilities.longestPrefixLength(g, "()(())(((("));
Assert.AreEqual("".Length, GrammarUtilities.longestPrefixLength(g, ")(()()())"));
}
public void EqualityTest6() // balanced parenthesis
{
String sg1 = "S -> S S|(S)|";
String sg2 = "X -> | X X | (L L->X) | X X)";
ContextFreeGrammar g1 = GrammarParser <char> .Parse(f1, sg1);
ContextFreeGrammar g2 = GrammarParser <char> .Parse(f1, sg2);
var res = GrammarUtilities.findDifferenceWithTimelimit(g1, g2, true, 100);
Assert.IsTrue(res.Item2.Count == 0 && res.Item3.Count == 0);
}
// Test for generated Grammars
public override bool isValid()
{
// Important! Set the length of words to be tested
var testWordsUpToLength = 5;
if (GrammarUtilities.getEquivalentCNF(this.grammar) == null)
{
return(false);
}
Tuple <int, int> tup = GrammarUtilities.getMinWordInAndOut(GrammarUtilities.getEquivalentCNF(this.grammar), testWordsUpToLength, this.inNeeded, this.outNeeded);
return(tup.Item1 >= this.inNeeded && tup.Item2 >= this.outNeeded);
}
public void prefixTest2() // a^n b^n
{
String sg1 = "S->aSb|S X| X->cX";
ContextFreeGrammar g = GrammarParser <char> .Parse(f1, sg1);
g = GrammarUtilities.getEquivalentCNF(g);
Assert.AreEqual(-2, GrammarUtilities.longestPrefixLength(g, "aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbb")); // full
Assert.AreEqual("a".Length, GrammarUtilities.longestPrefixLength(g, "a"));
Assert.AreEqual("".Length, GrammarUtilities.longestPrefixLength(g, "b"));
Assert.AreEqual("aab".Length, GrammarUtilities.longestPrefixLength(g, "aab"));
Assert.AreEqual("aabb".Length, GrammarUtilities.longestPrefixLength(g, "aabbb"));
Assert.AreEqual("aaaaaaaaaaaabbbbbbbbbbbb".Length, GrammarUtilities.longestPrefixLength(g, "aaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbababc"));
}
public void EqualityTest7() // empty grammars and invariants
{
String sg1 = "S -> S S|(S)|";
ContextFreeGrammar g1 = GrammarParser <char> .Parse(f1, sg1);
var res = GrammarUtilities.findDifferenceWithTimelimit(g1, null, true, 25);
Assert.IsTrue(res.Item1 == 0 && res.Item2.Count > 0 && res.Item3.Count == 0);
res = GrammarUtilities.findDifferenceWithTimelimit(null, g1, true, 25);
Assert.IsTrue(res.Item1 == 0 && res.Item2.Count == 0 && res.Item3.Count > 0);
res = GrammarUtilities.findDifferenceWithTimelimit(g1, g1, true, 25);
Assert.IsTrue(res.Item1 > 0 && res.Item2.Count == 0 && res.Item3.Count == 0);
res = GrammarUtilities.findDifferenceWithTimelimit(null, null, true, 30);
Assert.IsTrue(res.Item1 == 0 && res.Item2.Count == 0 && res.Item3.Count == 0);
}
private void AddCFGOfPDA(PDA <A, S> pda, string id, CancellationToken token)
{
var cfg = PDAToCFGConverter <A, S> .ToCFG(pda, token);
var cleanedCfg = CFGCleaner.RemoveUselessSymbols(cfg, token);
if (cleanedCfg == null)
{
noWordIsAccepted = true;
}
else
{
var cfgInCNF = GrammarUtilities.getEquivalentCNF(cleanedCfg);
contextFreeGrammarsInCNF.Add(id, cfgInCNF);
}
}
public void CYK_Test3()
{
String sg1 = "S -> A B C A-> B-> C->"; // = {""} Testing epsilon
ContextFreeGrammar g = GrammarParser <char> .Parse(f1, sg1);
g = GrammarUtilities.getEquivalentCNF(g);
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, ""));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ba"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ca"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "d"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "abcc"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "cba"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ababababababababababababababababababab"));
}
public WordsInGrammarProblem(ContextFreeGrammar grammar, int inNeeded, int outNeeded)
{
this.grammar = grammar;
this.inNeeded = inNeeded;
this.outNeeded = outNeeded;
numberOfShortWords = GrammarUtilities.generateShortestWords(grammar, shortLength).Count;
//calculate all possible short words (needed for qual and dif)
possibleShortWords = 0;
int termCount = grammar.GetNonVariableSymbols().Count();
int x = 1;
for (int i = 0; i <= shortLength; i++)
{
possibleShortWords += x;
x *= termCount;
}
}
public void CYK_Test1()
{
String sg1 = "S->aX X->bS|b"; // = (ab)* Aufg 1.1a
ContextFreeGrammar g = GrammarParser <char> .Parse(f1, sg1);
g = GrammarUtilities.getEquivalentCNF(g);
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "ab"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "abab"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "ababab"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "ababababababababababababababababababababab"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "a"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "b"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "c"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "aab"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ba"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "aabaabbabb"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ababababababababababababababababababa"));
}
public void prefixTest3() // balanced parenthesis () and {} Exercise 8.5
{
String sg1 = "S -> S S|(S)|{S}|";
ContextFreeGrammar g = GrammarParser <char> .Parse(f1, sg1);
g = GrammarUtilities.getEquivalentCNF(g);
Assert.AreEqual(-2, GrammarUtilities.longestPrefixLength(g, "(){()}")); // full
Assert.AreEqual("(){(".Length, GrammarUtilities.longestPrefixLength(g, "(){("));
Assert.AreEqual("()".Length, GrammarUtilities.longestPrefixLength(g, "()}"));
String sg2 = "S->A B| C D | A T | C U | S S T-> A B U->S D A->( B->) C->{ D->}";
g = GrammarParser <char> .Parse(f1, sg2);
g = GrammarUtilities.getEquivalentCNF(g);
Assert.AreEqual(-2, GrammarUtilities.longestPrefixLength(g, "(){()}")); // full
Assert.AreEqual("(){(".Length, GrammarUtilities.longestPrefixLength(g, "(){("));
Assert.AreEqual("()".Length, GrammarUtilities.longestPrefixLength(g, "()}"));
}
public void CYK_Test2()
{
String sg1 = "S->aSb|S X| X->cX"; // = a^n b^n Aufg 1.1b
ContextFreeGrammar g = GrammarParser <char> .Parse(f1, sg1);
g = GrammarUtilities.getEquivalentCNF(g);
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, ""));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "ab"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "aabb"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "aaabbb"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "aaaabbbb"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "a"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "b"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "c"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "aab"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ba"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "aabaabbabb"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ababababababababababababababababababab"));
}
public void CYK_Test4()
{
String sg1 = "S->A B C A->|a B->b| C->|c"; // = {"", a, b, c, ab, ac, bc, abc}
ContextFreeGrammar g = GrammarParser <char> .Parse(f1, sg1);
g = GrammarUtilities.getEquivalentCNF(g);
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, ""));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "a"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "b"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "c"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "ab"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "ac"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "bc"));
Assert.IsTrue(GrammarUtilities.isWordInGrammar(g, "abc"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ba"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ca"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "d"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "abcc"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "cba"));
Assert.IsFalse(GrammarUtilities.isWordInGrammar(g, "ababababababababababababababababababab"));
}
public AcceptanceResult <S> IsWordAccepted(IEnumerable <A> word)
{
var wordAsString = string.Join("", word.Select(w => w.ToString()));
if (noWordIsAccepted)
{
return(AcceptanceResult <S> .NoAcceptance());
}
var res = contextFreeGrammarsInCNF.Select(cfg => new KeyValuePair <string, bool>(cfg.Key, cfg.Value != null && GrammarUtilities.isWordInGrammar(cfg.Value, wordAsString))).ToList();
return(new AcceptanceResult <S>(res.ToDictionary(k => k.Key, k => k.Value)));
}
public GrammarToCNFProblem(ContextFreeGrammar grammar)
{
this.grammar = grammar;
sol = GrammarUtilities.getEquivalentCNF(grammar);
}
