public void AddDuplicate()
{
State state = new State();
Production p = new Production(new Terminal('x', 'y'));
Item itemA = new Item(p, state);
itemA.Add('x');
state.Add(itemA);
Item itemB = new Item(p, state);
itemB.Add('y');
state.Add(itemB);
}
public void Add()
{
State state = new State();
Item item = new Item(new Production(), state);
state.Add(item);
Assert.AreEqual(1, state.Count);
}
public void Contains()
{
State s = new State();
Item item = new Item(new Production(), s);
Assert.IsFalse(s.Contains(item));
s.Add(item);
Assert.IsTrue(s.Contains(item));
}
public void Enumerate()
{
State state = new State();
Item item = new Item(new Production(), state);
state.Add(item);
Assert.AreEqual(item, state[0]);
for (int i = 0; i < state.Count; i++)
{
item = state[i];
}
}
public void GetItems()
{
State state = new State();
Nonterminal nt = new Nonterminal();
Production p = new Production(nt);
nt.Add(p);
Item item = new Item(p, state);
state.Add(item);
state.Add(new Item(new Production(), state));
IList<Item> items = state.GetItems(p);
Assert.AreEqual(1, items.Count);
Assert.AreSame(item, items[0]);
}
public void ImportIncompatible()
{
Production p = new Production(new Terminal('a', 'b'));
Item item = new Item(p, new State());
State s = new State();
Item next = item.NextItem;
next.Add('a');
s.Add(next);
Item newNext = item.NextItem;
newNext.Add('b');
s.Import(newNext);
}
public void Import()
{
Production p = new Production(new Terminal('a', 'b'));
Item item = new Item(p, new State());
State s = new State();
Item next = item.NextItem;
next.Add('a');
s.Add(next);
Item imported = s.Import(item.NextItem);
Assert.AreSame(next, imported);
item = new Item(new Production(), new State());
imported = s.Import(item);
Assert.AreSame(item, imported);
}
private IList<object> Parse(TextReader input)
{
if (input == null) throw new ArgumentNullException();
State initial = new State();
initial.Add(new Item(startProduction, initial));
State current = initial;
State next = new State();
do
{
IDictionary<Production, IList<Item>> completedNullable =
new Dictionary<Production, IList<Item>>();
for (int i = 0; i < current.Count; i++)
{
Item item = current[i];
if (!item.AtEnd && item.Symbol is Nonterminal)
{
Predictor(current, item, completedNullable);
}
else if (!item.AtEnd && item.Symbol is Terminal)
{
Scanner(item, next, input.Peek());
}
else
{
Completer(current, item, completedNullable);
}
}
current = next;
next = new State();
}
while (input.Read() != -1 && current.Count > 0);
if (current.Count == 1 &&
current[0].AtEnd &&
current[0].Production == startProduction &&
current[0].Parent == initial)
{
return current[0].Reduce();
}
else
{
return new List<object>();
}
}
private void Scanner(Item item, State next, int ch)
{
Debug.Assert(!item.AtEnd && item.Symbol is Terminal);
Terminal t = item.Symbol as Terminal;
if (t.Contains(ch))
{
Item newItem = item.NextItem;
newItem.Add(ch);
next.Add(newItem);
}
}
private void Predictor(
State state,
Item item,
IDictionary<Production,IList<Item>> completedNullable)
{
Debug.Assert(!item.AtEnd && item.Symbol is Nonterminal);
Nonterminal nt = item.Symbol as Nonterminal;
foreach (Production p in nt.Productions)
{
Item newItem = new Item(p, state);
if (!state.Contains(newItem))
{
state.Add(newItem);
ShiftCompletedNullable(state, newItem, completedNullable);
}
}
}