private static bool TryDerive([NotNull, ItemNotNull] List <Symbol> tape,
int start,
[NotNull] GrammarRule1 rule, ITracker tracker, [CanBeNull] Dictionary <GrammarRule1, bool> used)
{
if (tape.Count < start + rule.LeftHandSide.Count)
{
return(false);
}
var sublist = tape.GetRange(start, rule.LeftHandSide.Count);
if (!sublist.SequenceEqual(rule.LeftHandSide))
{
return(false);
}
if (used != null)
{
used[rule] = true;
}
tape.RemoveRange(start, rule.LeftHandSide.Count);
tape.InsertRange(start, rule.RightHandSide);
tracker.Track(tape, rule);
return(true);
}
public static bool TryDerive([NotNull, ItemNotNull] this List <Symbol> tape, [NotNull] GrammarRule1 rule,
ITracker tracker, [CanBeNull] Dictionary <GrammarRule1, bool> used) =>
tape.Where((t, index) => TryDerive(tape, index, rule, tracker, used)).Any();
public void Track(IList <Symbol> track, GrammarRule1 rule) => Rules.Add(rule);
