protected virtual StringTemplate WalkFixedDFAGeneratingStateMachine(
TemplateGroup templates,
DFA dfa,
DFAState s,
int k)
{
//System.Console.Out.WriteLine( "walk " + s.stateNumber + " in dfa for decision " + dfa.decisionNumber );
if (s.IsAcceptState)
{
StringTemplate dfaST2 = templates.GetInstanceOf("dfaAcceptState");
dfaST2.SetAttribute("alt", s.GetUniquelyPredictedAlt());
return(dfaST2);
}
// the default templates for generating a state and its edges
// can be an if-then-else structure or a switch
string dfaStateName = "dfaState";
string dfaLoopbackStateName = "dfaLoopbackState";
string dfaOptionalBlockStateName = "dfaOptionalBlockState";
string dfaEdgeName = "dfaEdge";
if (_parentGenerator.CanGenerateSwitch(s))
{
dfaStateName = "dfaStateSwitch";
dfaLoopbackStateName = "dfaLoopbackStateSwitch";
dfaOptionalBlockStateName = "dfaOptionalBlockStateSwitch";
dfaEdgeName = "dfaEdgeSwitch";
}
StringTemplate dfaST = templates.GetInstanceOf(dfaStateName);
if (dfa.NFADecisionStartState.decisionStateType == NFAState.LOOPBACK)
{
dfaST = templates.GetInstanceOf(dfaLoopbackStateName);
}
else if (dfa.NFADecisionStartState.decisionStateType == NFAState.OPTIONAL_BLOCK_START)
{
dfaST = templates.GetInstanceOf(dfaOptionalBlockStateName);
}
dfaST.SetAttribute("k", k);
dfaST.SetAttribute("stateNumber", s.StateNumber);
dfaST.SetAttribute("semPredState",
s.IsResolvedWithPredicates);
/*
* string description = dfa.getNFADecisionStartState().Description;
* description = parentGenerator.target.getTargetStringLiteralFromString( description );
* //System.Console.Out.WriteLine( "DFA: " + description + " associated with AST " + dfa.getNFADecisionStartState() );
* if ( description != null )
* {
* dfaST.SetAttribute( "description", description );
* }
*/
int EOTPredicts = NFA.INVALID_ALT_NUMBER;
DFAState EOTTarget = null;
//System.Console.Out.WriteLine( "DFA state " + s.stateNumber );
for (int i = 0; i < s.NumberOfTransitions; i++)
{
Transition edge = (Transition)s.GetTransition(i);
//System.Console.Out.WriteLine( "edge " + s.stateNumber + "-" + edge.label.ToString() + "->" + edge.target.stateNumber );
if (edge.Label.Atom == Label.EOT)
{
// don't generate a real edge for EOT; track alt EOT predicts
// generate that prediction in the else clause as default case
EOTTarget = (DFAState)edge.Target;
EOTPredicts = EOTTarget.GetUniquelyPredictedAlt();
/*
* System.Console.Out.WriteLine("DFA s"+s.stateNumber+" EOT goes to s"+
* edge.target.stateNumber+" predicates alt "+
* EOTPredicts);
*/
continue;
}
StringTemplate edgeST = templates.GetInstanceOf(dfaEdgeName);
// If the template wants all the label values delineated, do that
if (edgeST.impl.TryGetFormalArgument("labels") != null)
{
List <string> labels = edge.Label.Set.Select(value => _parentGenerator.GetTokenTypeAsTargetLabel(value)).ToList();
edgeST.SetAttribute("labels", labels);
}
else
{ // else create an expression to evaluate (the general case)
edgeST.SetAttribute("labelExpr",
_parentGenerator.GenLabelExpr(templates, edge, k));
}
// stick in any gated predicates for any edge if not already a pred
if (!edge.Label.IsSemanticPredicate)
{
DFAState target = (DFAState)edge.Target;
SemanticContext preds =
target.GetGatedPredicatesInNFAConfigurations();
if (preds != null)
{
//System.Console.Out.WriteLine( "preds=" + target.getGatedPredicatesInNFAConfigurations() );
StringTemplate predST = preds.GenExpr(_parentGenerator,
_parentGenerator.Templates,
dfa);
edgeST.SetAttribute("predicates", predST);
}
}
StringTemplate targetST =
WalkFixedDFAGeneratingStateMachine(templates,
dfa,
(DFAState)edge.Target,
k + 1);
edgeST.SetAttribute("targetState", targetST);
dfaST.SetAttribute("edges", edgeST);
//System.Console.Out.WriteLine( "back to DFA " + dfa.decisionNumber + "." + s.stateNumber );
}
// HANDLE EOT EDGE
if (EOTPredicts != NFA.INVALID_ALT_NUMBER)
{
// EOT unique predicts an alt
dfaST.SetAttribute("eotPredictsAlt", EOTPredicts);
}
else if (EOTTarget != null && EOTTarget.NumberOfTransitions > 0)
{
// EOT state has transitions so must split on predicates.
// Generate predicate else-if clauses and then generate
// NoViableAlt exception as else clause.
// Note: these predicates emanate from the EOT target state
// rather than the current DFAState s so the error message
// might be slightly misleading if you are looking at the
// state number. Predicates emanating from EOT targets are
// hoisted up to the state that has the EOT edge.
for (int i = 0; i < EOTTarget.NumberOfTransitions; i++)
{
Transition predEdge = (Transition)EOTTarget.GetTransition(i);
StringTemplate edgeST = templates.GetInstanceOf(dfaEdgeName);
edgeST.SetAttribute("labelExpr",
_parentGenerator.GenSemanticPredicateExpr(templates, predEdge));
// the target must be an accept state
//System.Console.Out.WriteLine( "EOT edge" );
StringTemplate targetST =
WalkFixedDFAGeneratingStateMachine(templates,
dfa,
(DFAState)predEdge.Target,
k + 1);
edgeST.SetAttribute("targetState", targetST);
dfaST.SetAttribute("edges", edgeST);
}
}
return(dfaST);
}
