// Return how many words of length UP TO 'lenght' are in/out of the language
public static Tuple <int, int> getMinWordInAndOut(ContextFreeGrammar grammar, int length, int minAcc, int minRej)
{
int acc = 0, rej = 0;
var literals = grammar.GetNonVariableSymbols();
HashSet <string> wordsOfEqualLength = new HashSet <string>();
for (int i = 0; i <= length; i++)
{
if (wordsOfEqualLength.Count == 0)
{
wordsOfEqualLength.Add("");
}
else
{
var cur = new HashSet <string>();
foreach (string word in wordsOfEqualLength)
{
foreach (GrammarSymbol literal in literals)
{
cur.Add(word + literal.ToString());
}
}
wordsOfEqualLength = cur;
}
// Checking for each word of a particular length if it is accepted by the language
foreach (string word in wordsOfEqualLength)
{
if (isWordInGrammar(grammar, word))
{
acc++;
}
else
{
rej++;
}
}
if (acc >= minAcc && rej >= minRej)
{
break;
}
}
return(new Tuple <int, int>(acc, rej));
}
public static Tuple <int, IEnumerable <String> > gradeWordsInGrammar(ContextFreeGrammar grammar, IEnumerable <String> wordsIn, IEnumerable <String> wordsOut, int maxGrade)
{
int cases = 0;
double correct = 0;
var terminals = new List <char>();
foreach (GrammarSymbol s in grammar.GetNonVariableSymbols())
{
terminals.Add(s.ToString()[0]);
}
List <String> feedback = new List <String>();
HashSet <String> done = new HashSet <String>(); //for duplicate checking
foreach (String w in wordsIn)
{
cases++;
//handle duplicates
if (done.Contains(w))
{
feedback.Add(String.Format("The word \"{0}\" was used more than once!", w));
continue;
}
else
{
done.Add(w);
}
int prefixLength = GrammarUtilities.longestPrefixLength(grammar, w);
if (prefixLength < 0)
{
correct++; //correct
}
else //wrong
{
feedback.Add(String.Format("The word \"{0}\" isn't in the language of the grammar! (hint: the word '{1}' is still possible prefix)", w, w.Substring(0, prefixLength)));
}
}
foreach (String w in wordsOut)
{
cases++;
//handle duplicates
if (done.Contains(w))
{
feedback.Add(String.Format("The word \"{0}\" was used more than once!", w));
continue;
}
else
{
done.Add(w);
}
if (!GrammarUtilities.isWordInGrammar(grammar, w)) //correct
{
//only useful terminals?
bool allUsefull = true;
char problem = 'a';
foreach (char c in w)
{
if (!terminals.Contains(c))
{
allUsefull = false;
problem = c;
break;
}
}
if (allUsefull)
{
correct += 1; //full points
}
else //only half the points
{
correct += 0.5;
feedback.Add(String.Format("The word \"{0}\" uses the symbol '{1}' that is not part of the alphabet...", w, problem));
}
}
else //wrong
{
feedback.Add(String.Format("The word \"{0}\" is in the language of the grammar!", w));
}
}
int grade = (int)Math.Floor(correct * maxGrade / (double)cases);
//all correct?
if (grade == maxGrade)
{
feedback.Add("Correct!");
}
return(Tuple.Create(grade, (IEnumerable <String>)feedback));
}
