public override IDerivation Visit(NonTerminal aSymbol, DerivationContext aContext)
{
tGraph graph = (aContext as BuildGraphContext).BuildingGraph;
if ((aSymbol.CycicKind & CycicKind.CyclicOrigin) > 0)
{
graph.ensureExistsNode(aSymbol.CounterName, aSymbol.Text);
graph.ensureExistsNode(aSymbol.CyclicToOccurence, aSymbol.Text);
tEdge e = graph.addEdge(aSymbol.CounterName, aSymbol.CyclicToOccurence);
if (e != null)
{
e.CustomAttributes = GrammarGraphEdgeAttrs.IsPunktir;
}
}
if (aSymbol.CycicKind == CycicKind.None ||
aSymbol.CycicKind == CycicKind.CyclicPropagated)
{
aSymbol.FindItsRule().Expand(aContext);
}
return(null);
}
private tEdge addEdge(DerivationContext aContext, IPhrase aPhr, IPhrase aParent)
{
tGraph graph = (aContext as BuildGraphContext).BuildingGraph;
string fromName = "unk";
string toName = "unk";
// determine fromName
if (aParent == null)
{
fromName = aContext.Grammar.MainSymbol.CounterName;
graph.ensureExistsNode(fromName, aContext.Grammar.MainSymbol.Text);
}
else
{
NonTerminal parentNt = aParent as NonTerminal;
if (parentNt != null)
{
fromName = parentNt.CounterName;
graph.ensureExistsNode(parentNt.CounterName, parentNt.Text);
}
else
{
fromName = (aContext as BuildGraphContext).GeneratedToName;
Debug.Assert(!string.IsNullOrEmpty(fromName), "Не должно быть");
}
}
// determine toName
NonTerminal nonTerminal = aPhr as NonTerminal;
Terminal terminal = aPhr as Terminal;
if (nonTerminal != null)
{
toName = nonTerminal.CounterName;
string text = nonTerminal.Text;
if ((nonTerminal.CycicKind & CycicKind.SkippedAsSeen) > 0)
{
text += " *";
}
graph.ensureExistsNode(toName, text);
}
else if (terminal != null)
{
string text = string.IsNullOrEmpty(terminal.Text) ? "e" : terminal.Text;
tNode n = graph.addNonUniqueNode(text);
toName = n.Name;
n.CustomAttributes = "term";
}
else
{
toName = graph.addNonUniqueNode(aPhr.ToString()).Name;
//надо запомнить это в контексте
(aContext as BuildGraphContext).GeneratedToName = toName;
}
tEdge e = graph.addEdge(fromName, toName);
if (e == null)
{
Debug.WriteLine("не создалась дуга, потому что нет вершин");
}
return(e);
}
