private void Shifter(Msg item)
{
var prevTops = gss.Topmost.ToArray();
gss.PushLayer();
foreach (var current in prevTops)
{
int?shift;
if (GetParserActions(current.State, item.Id, out shift, null) && shift.HasValue)
{
var rightSib = gss.FindTopmost(shift.Value);
if (rightSib != null)
{
gss.AddLink(rightSib, current, item);
}
else
{
rightSib = gss.AddTopmost(shift.Value);
gss.AddLink(rightSib, current, item);
}
}
}
}
public IReceiver <Msg> Next(Msg envelope)
{
gss.BeginEdit();
N.Clear();
var front = gss.FrontArray;
MsgData data = envelope.FirstData;
do
{
int lookahead = data.Token;
Actor(lookahead);
Reducer(lookahead);
if (accepted)
{
int count = gss.Count;
for (int i = 0; i != count; ++i)
{
var node = front[i];
if (IsAccepting(node.State))
{
producer.Result = node.FirstLink.Label;
break;
}
}
}
var termValue = producer.CreateLeaf(envelope, data);
N[GetNKey(lookahead, gss.CurrentLayer + 1)] = termValue;
for (int i = 0; i != gss.Count; ++i)
{
var frontNode = front[i];
// Plan shift
var shift = GetShift(frontNode.State, lookahead);
if (shift >= 0)
{
Q.Enqueue(new PendingShift(frontNode, shift, lookahead));
}
// Shift and plan reduce
var action = GetShiftReduce(frontNode.State, lookahead);
if (action.Kind == ParserActionKind.ShiftReduce)
{
PlanShiftReduce(
frontNode,
lookahead,
termValue,
action.ProductionId,
action.Size);
}
}
data = data.Next;
}while (data != null);
gss.PushLayer();
Shifter();
// Run reducer again to complete
// shift-reduce and goto-reduce actions.
Reducer();
#if DIAGNOSTICS
if (!isVerifier)
{
using (var graphView = new GvGraphView("GlrState" + gss.CurrentLayer + ".gv"))
{
gss.WriteGraph(graphView, grammar, stateToPriorToken);
}
}
#endif
if (gss.IsEmpty)
{
if (accepted)
{
return(FinalReceiver <Msg> .Instance);
}
if (isVerifier)
{
return(null);
}
gss.Undo(0); // restore state before the current input token
{
var message = new StringBuilder();
message
.Append("Unexpected token ")
.Append(grammar.SymbolName(envelope.Id))
.Append(" in state stacks: {");
bool firstStack = true;
for (int i = 0; i != gss.Count; ++i)
{
var node = gss.FrontArray[i];
if (firstStack)
{
firstStack = false;
}
else
{
message.Append(", ");
}
message.Append("[");
var n = node;
bool firstState = true;
while (true)
{
if (firstState)
{
firstState = false;
}
else
{
message.Append(", ");
}
message.Append(n.State);
if (n.State == 0)
{
break;
}
n = n.FirstLink.LeftNode;
}
message.Append("]");
}
message.Append("}");
logging.Write(
new LogEntry
{
Severity = Severity.Verbose,
Location = envelope.Location,
HLocation = envelope.HLocation,
Message = message.ToString()
});
}
return(RecoverFromError(envelope));
}
gss.EndEdit();
this.priorInput = envelope;
return(this);
}