private bool TryBuildTreeFromStack(bool StopOnError)
{
TValue VT = (TValue)Activator.CreateInstance(typeof(TValue));
Stack <KeyValuePair <int, int> > BackTrack = new Stack <KeyValuePair <int, int> >();//стек пунктов для перебора с возвратом
HashSet <KeyValuePair <int, int> > CheckedKernelItems = new HashSet <KeyValuePair <int, int> >();
while (StateStack.TopElement().number != 0)
{
//если восстановление по ходу разбора
//то выходим, встретив состояние, допускающее error
if (StopOnError)
{
if (FsaState.ParserTable != null &&
FsaState.ParserTable.ContainsKey(errorToken) &&
FsaState.ParserTable[errorToken] > 0) // shift
{
return(true);
}
}
State state = StateStack.TopElement();
int ruleNum = 0; //номер пункта
int pointPos = 0; //позиция точки в выбранной продукци
//Формируем список еще не посещенных пунктов
List <KeyValuePair <int, int> > ValidKernelItems = new List <KeyValuePair <int, int> >();
foreach (KeyValuePair <int, int> p in state.kernelItems)
{
if (!CheckedKernelItems.Contains(p))
{
ValidKernelItems.Add(p);
}
}
if (ValidKernelItems.Count == 0)
{
//непосещенных пунктов не осталось - возврат
KeyValuePair <int, int> p = BackTrack.Pop();
ruleNum = p.Key;
pointPos = p.Value;
}
else
{
//Среди непосещенных находим пункт с точкой в самой правой позиции
foreach (KeyValuePair <int, int> p in ValidKernelItems)
{
if (p.Value > pointPos)
{
pointPos = p.Value;
ruleNum = p.Key;
}
}
if (pointPos == 1)
{
//точка в 1 позиции - добавляем пункты на стек и берем последний из них
foreach (KeyValuePair <int, int> p in ValidKernelItems)
{
BackTrack.Push(p);
CheckedKernelItems.Add(p);
}
KeyValuePair <int, int> p2 = BackTrack.Pop();
ruleNum = p2.Key;
pointPos = p2.Value;
}
else
{
//точка в 2+ позиции - готовимся к новому запуску перебора с возвратом
CheckedKernelItems.Clear();
BackTrack.Clear();
}
}
int count = rules[ruleNum].RightHandSide.Length - pointPos;
//add items to stacks
for (int i = 0; i < count; ++i)
{
valueStack.Push(VT);
locationStack.Push(CurrentLocationSpan);
StateStack.Push(state);
}
//reduce
Reduce(ruleNum);
}
return(true);
}
/// <summary>
/// Main entry point of the Shift-Reduce Parser.
/// </summary>
/// <returns>True if parse succeeds, else false for
/// unrecoverable errors</returns>
public bool Parse()
{
Initialize(); // allow derived classes to instantiate rules, states and nonTerminals
NextToken = 0;
FsaState = states[0];
StateStack.Push(FsaState);
valueStack.Push(CurrentSemanticValue);
LocationStack.Push(CurrentLocationSpan);
while (true)
{
#if TRACE_ACTIONS
Console.Error.WriteLine("Entering state {0} ", FsaState.number);
DisplayStack();
#endif
int action = FsaState.defaultAction;
if (FsaState.ParserTable != null)
{
if (NextToken == 0)
{
// We save the last token span, so that the location span
// of production right hand sides that begin or end with a
// nullable production will be correct.
LastSpan = scanner.yylloc;
NextToken = scanner.yylex();
#if TRACE_ACTIONS
Console.Error.WriteLine("Reading: Next token is {0}", TerminalToString(NextToken));
#endif
}
#if TRACE_ACTIONS
else
{
Console.Error.WriteLine("Next token is still {0}", TerminalToString(NextToken));
}
#endif
if (FsaState.ParserTable.ContainsKey(NextToken))
{
action = FsaState.ParserTable[NextToken];
}
}
if (action > 0) // shift
{
Shift(action);
}
else if (action < 0) // reduce
{
try {
Reduce(-action);
if (action == -1) // accept
{
return(true);
}
}
catch (AbortException) {
return(false);
}
catch (AcceptException) {
return(true);
}
catch (ErrorException) {
if (!ErrorRecovery())
{
return(false);
}
else
{
throw; // Rethrow x, preserving information.
}
}
}
else if (action == 0 && !ErrorRecovery()) // error
{
return(false);
}
}
}
public bool Parse()
{
Initialize();
NextToken = 0;
FsaState = states[0];
StateStack.Push(FsaState);
valueStack.Push(CurrentSemanticValue);
LocationStack.Push(CurrentLocationSpan);
while (true)
{
#if TRACE_ACTIONS
Console.Error.WriteLine("Entering state {0} ", FsaState.number);
#endif
int action = FsaState.defaultAction;
if (FsaState.ParserTable != null)
{
if (NextToken == 0)
{
#if TRACE_ACTIONS
Console.Error.Write("Reading a token: ");
#endif
LastSpan = scanner.yylloc;
NextToken = scanner.yylex();
}
#if TRACE_ACTIONS
Console.Error.WriteLine("Next token is {0}", TerminalToString(NextToken));
#endif
if (FsaState.ParserTable.ContainsKey(NextToken))
{
action = FsaState.ParserTable[NextToken];
}
}
if (action > 0)
{
Shift(action);
}
else if (action < 0)
{
try
{
Reduce(-action);
if (action == -1)
{
return(true);
}
}
catch (Exception x)
{
if (x is AbortException)
{
return(false);
}
else if (x is AcceptException)
{
return(true);
}
else if (x is ErrorException && !ErrorRecovery())
{
return(false);
}
else
{
throw;
}
}
}
else if (action == 0)
{
if (!ErrorRecovery())
{
return(false);
}
}
}
}