/// <summary>
/// Gets the LR(0) graph
/// </summary>
/// <returns>The corresponding LR(0) graph</returns>
private Graph GetGraphLR0()
{
// Create the base LR(0) graph
Variable axiom = grammar.GetVariable(Grammar.GENERATED_AXIOM);
ItemLR0 item = new ItemLR0(axiom.Rules[0], 0);
StateKernel kernel = new StateKernel();
kernel.AddItem(item);
State state0 = kernel.GetClosure();
Graph result = new Graph(state0);
// Construct the graph
foreach (State state in result.States)
{
state.BuildReductions(new StateReductionsLR0());
}
return(result);
}
/// <summary>
/// Closes this item to a set of items
/// </summary>
/// <param name="closure">The list to close</param>
/// <param name="map">The current helper map</param>
public override void CloseTo(List <Item> closure, Dictionary <Rule, Dictionary <int, List <Item> > > map)
{
// the item was of the form [Var -> alpha .] (reduction)
// nothing to do
if (Action == LRActionCode.Reduce)
{
return;
}
// Get the next symbol in the item
Symbol next = GetNextSymbol();
// Here the item is of the form [Var -> alpha . next beta]
// If the next symbol is not a variable : do nothing
// If the next symbol is a variable :
Variable nextVar = next as Variable;
if (nextVar == null)
{
return;
}
foreach (Rule rule in nextVar.Rules)
{
if (!map.ContainsKey(rule))
{
map.Add(rule, new Dictionary <int, List <Item> >());
}
Dictionary <int, List <Item> > sub = map[rule];
if (sub.ContainsKey(0))
{
continue;
}
List <Item> list = new List <Item>();
sub.Add(0, list);
ItemLR0 child = new ItemLR0(rule, 0);
closure.Add(child);
list.Add(child);
}
}
