private void ComputeLr0ItemSetKernelsAndGotoLookup(out LrItemSetCollection itemSets, out Dictionary <int, Dictionary <SymbolId, int> > gotos, out int acceptIndex)
{
itemSets = new LrItemSetCollection();
gotos = new Dictionary <int, Dictionary <SymbolId, int> >();
var itemSetByKernels = new Dictionary <IEnumerable <LrItem>, LrItemSet>(SetEqualityComparer <LrItem> .Default);
var queue = new Queue <LrItemSet>();
var startItem = new LrItemSet(new LrItem(this.ProductionRulesBySymbol[this.Init].Single(), 0, true));
this.Lr0ComputeClosureNonterminals(startItem);
itemSets.StartState = startItem;
acceptIndex = this.ProductionRulesBySymbol[this.Init].Single().Index;
startItem.Index = itemSets.Count;
itemSets.Add(startItem);
itemSetByKernels.Add(startItem.Kernels.ToArray(), startItem);
queue.Enqueue(startItem);
while (queue.Count > 0)
{
var itemSet = queue.Dequeue();
var gotoLookup = this.Lr0GotoKernels(itemSet);
var gotosForState = new Dictionary <SymbolId, int>();
gotos.Add(itemSet.Index, gotosForState);
foreach (var symbol in gotoLookup.Keys)
{
if (!itemSetByKernels.TryGetValue(gotoLookup[symbol].Kernels, out var gotoState))
{
gotoState = gotoLookup[symbol];
this.Lr0ComputeClosureNonterminals(gotoState);
gotoState.Index = itemSets.Count;
itemSets.Add(gotoState);
itemSetByKernels.Add(gotoState.Kernels.ToArray(), gotoState);
queue.Enqueue(gotoState);
}
gotosForState.Add(symbol, gotoState.Index);
}
}
}
private Dictionary <StateKey <SymbolId>, int> ComputeGotoLookup(SymbolMetaDictionary symbolMeta, LrItemSetCollection itemSets)
{
var gotos = new Dictionary <StateKey <SymbolId>, int>();
var itemSetByKernels = itemSets.ToDictionary(s => s.Kernels.ToArray(), s => s, SetEqualityComparer <LrItem> .Default);
foreach (var itemSet in itemSets)
{
foreach (var sym in symbolMeta.Keys)
{
// Compute dynamic GOTO
var gotoClosure = this.Lr1Closure(symbolMeta, new LrItemSet(itemSet
.Where(item => (item.Marker < item.Length) && item.Rule.RuleSymbolIds[item.Marker].Equals(sym))
.Select(item => new LrItem(item.Rule, item.Marker + 1, true))));
if (!gotoClosure.Any())
{
continue;
}
var key = new StateKey <SymbolId>(itemSet.Index, sym);
if (gotos.ContainsKey(key))
{
continue;
}
// Match the dynamic GOTO to an actual state
if (itemSetByKernels.TryGetValue(gotoClosure.Kernels, out var existingGoto))
{
gotos.Add(key, existingGoto.Index);
}
}
}
return(gotos);
}