private static XElement TryToGradeConstructionProblem(XElement xmlPdaCorrect, XElement xmlPdaAttempt, XElement xmlGiveStackAlphabet, XElement xmlMaxGrade, CancellationToken token)
{
var pdaCorrect = PDA <char, char> .FromXml(xmlPdaCorrect);
pdaCorrect.CreateRunner(token);
var pdaAttempt = PDA <char, char> .FromXml(xmlPdaAttempt);
pdaAttempt.CreateRunner(token);
var giveStackAlphabet = bool.Parse(xmlGiveStackAlphabet.Value);
var maxGrade = int.Parse(xmlMaxGrade.Value);
var alphabet = PDAXmlParser.ParseAlphabetFromXmlPDA(xmlPdaCorrect);
Assertion.Assert(Enumerable.SequenceEqual(alphabet, PDAXmlParser.ParseAlphabetFromXmlPDA(xmlPdaAttempt)), "the alphabets of the given PDAs are not the same");
var stackAlphabetCorrect = PDAXmlParser.ParseStackAlphabetFromXmlPDA(xmlPdaCorrect);
var stackAlphabetAttempt = PDAXmlParser.ParseStackAlphabetFromXmlPDA(xmlPdaAttempt);
Assertion.Assert(!giveStackAlphabet || Enumerable.SequenceEqual(stackAlphabetCorrect, stackAlphabetAttempt), "if the stack-alphabet is given for the solver, the attempt pda has to have the same stack-alphabet");
int statesDiff = pdaAttempt.States.Count - pdaCorrect.States.Count;
int stackDiff = stackAlphabetAttempt.Count - stackAlphabetCorrect.Count;
PDAEqualityResult <char, char> pdaEqualityResult;
pdaEqualityResult = new PDAEqualityResult <char, char>(pdaCorrect, pdaAttempt, alphabet, maximumWordLengthTested, maximumNumberOfWords, maximumMilliSeconds);
if (pdaEqualityResult.PdaCorrectIsinconsistent)
{
return(Grader.CreateXmlFeedback(maxGrade, new List <string>()
{
"Oops! Seems like your tutor created an inconsistent pda...therefore, you get the full grade ;)"
}));
}
int joinSize = pdaEqualityResult.NumberOfWordsAcceptedByAtLeastOne;
double proportion = joinSize == 0 ? 1 : (double)pdaEqualityResult.NumberOfWordsAcceptedByBoth / joinSize;
int grade = (int)(maxGrade * proportion);
var feedback = new List <string>();
if (!pdaEqualityResult.AreEqual)
{
if (pdaEqualityResult.WordsInPdaCorrectButNotInPdaAttempt.Count() == 0 && pdaEqualityResult.WordsInPdaAttemptButNotInPdaCorrect.Count() > 0)
{
feedback.Add(string.Format(HintSuperset));
}
else if (pdaEqualityResult.WordsInPdaAttemptButNotInPdaCorrect.Count() == 0 && pdaEqualityResult.WordsInPdaCorrectButNotInPdaAttempt.Count() > 0)
{
feedback.Add(string.Format(HintSubset));
}
if (pdaEqualityResult.WordsInPdaCorrectButNotInPdaAttempt.Count() > 0)
{
feedback.Add(string.Format(ErrorWordFalselyExcluded, FindWordWithMinimumLength(pdaEqualityResult.WordsInPdaCorrectButNotInPdaAttempt)));
}
if (pdaEqualityResult.WordsInPdaAttemptButNotInPdaCorrect.Count() > 0)
{
feedback.Add(string.Format(ErrorWordFalselyIncluded, FindWordWithMinimumLength(pdaEqualityResult.WordsInPdaAttemptButNotInPdaCorrect)));
}
}
if (pdaEqualityResult.InconsistentWordsInPdaAttempt.Count() > 0)
{
grade = Math.Max(grade - 1, 0);
var tuple = FindElementWithMinimumProperty(pdaEqualityResult.InconsistentWordsInPdaAttempt, t => t.Item1.Length);
feedback.Add(string.Format(ErrorInconsistentAcceptanceCondition, tuple.Item1, tuple.Item2, !tuple.Item2));
}
if (statesDiff > 0 || stackDiff > 0)
{
grade = Math.Max(0, grade - 1);
if (statesDiff > 0)
{
feedback.Add(string.Format(ErrorToManyStates, pdaAttempt.States.Count, pdaCorrect.States.Count));
}
if (stackDiff > 0)
{
feedback.Add(string.Format(ErrorToManyStackSymbols, stackAlphabetAttempt.Count, stackAlphabetCorrect.Count));
}
}
if (grade == maxGrade)
{
feedback.Add("Perfect!");
}
else if (pdaEqualityResult.AreEqual && pdaEqualityResult.InconsistentWordsInPdaAttempt.Count() == 0)
{
feedback.Add("Correct (but not perfect)!");
}
return(Grader.CreateXmlFeedback(grade, feedback));
}