public static Nfa Match(int symbol)
{
State startState = new State();
State endState = new State();
startState.AddTransition(new MatchRangeTransition(endState, Interval.FromBounds(symbol, symbol)));
return(new Nfa(startState, endState));
}
public static Nfa MatchAny(params int[] symbols)
{
State startState = new State();
State endState = new State();
foreach (var symbol in symbols)
{
startState.AddTransition(new MatchRangeTransition(endState, Interval.FromBounds(symbol, symbol)));
}
return(new Nfa(startState, endState));
}
/** Given the set of possible values (rather than, say UNICODE or MAXINT),
* return a new set containing all elements in vocabulary, but not in
* this. The computation is (vocabulary - this).
*
* 'this' is assumed to be either a subset or equal to vocabulary.
*/
public virtual IntervalSet Complement(Interval vocabulary)
{
if (vocabulary.EndInclusive < MinElement || vocabulary.Start > MaxElement)
{
// nothing in common with this set
return(null);
}
int n = intervals.Count;
if (n == 0)
{
return(IntervalSet.Of(vocabulary));
}
IntervalSet compl = new IntervalSet();
Interval first = intervals[0];
// add a range from 0 to first.Start constrained to vocab
if (first.Start > vocabulary.Start)
{
compl.Intervals.Add(Interval.FromBounds(vocabulary.Start, first.Start - 1));
}
for (int i = 1; i < n; i++)
{
if (intervals[i - 1].EndInclusive >= vocabulary.EndInclusive)
{
break;
}
if (intervals[i].Start <= vocabulary.Start)
{
continue;
}
if (intervals[i - 1].EndInclusive == intervals[i].Start - 1)
{
continue;
}
compl.Intervals.Add(Interval.FromBounds(Math.Max(vocabulary.Start, intervals[i - 1].EndInclusive + 1), Math.Min(vocabulary.EndInclusive, intervals[i].Start - 1)));
//// from 2nd interval .. nth
//Interval previous = intervals[i - 1];
//Interval current = intervals[i];
//IntervalSet s = IntervalSet.Of( previous.EndInclusive + 1, current.Start - 1 );
//IntervalSet a = (IntervalSet)s.And( vocabularyIS );
//compl.AddAll( a );
}
Interval last = intervals[n - 1];
// add a range from last.EndInclusive to maxElement constrained to vocab
if (last.EndInclusive < vocabulary.EndInclusive)
{
compl.Intervals.Add(Interval.FromBounds(last.EndInclusive + 1, vocabulary.EndInclusive));
//IntervalSet s = IntervalSet.Of( last.EndInclusive + 1, maxElement );
//IntervalSet a = (IntervalSet)s.And( vocabularyIS );
//compl.AddAll( a );
}
return(compl);
}