public virtual DFA CreateLookaheadDFA( int decision, bool wackTempStructures )
{
Decision d = GetDecision( decision );
string enclosingRule = d.startState.enclosingRule.Name;
Rule r = d.startState.enclosingRule;
//[email protected]("createLookaheadDFA(): "+enclosingRule+" dec "+decision+"; synprednames prev used "+synPredNamesUsedInDFA);
NFAState decisionStartState = GetDecisionNFAStartState( decision );
DateTime startDFA = DateTime.MinValue;
DateTime stopDFA = DateTime.MinValue;
if ( composite.WatchNFAConversion )
{
Console.Out.WriteLine( "--------------------\nbuilding lookahead DFA (d="
+ decisionStartState.DecisionNumber + ") for " +
decisionStartState.Description );
startDFA = DateTime.Now;
}
DFA lookaheadDFA = DFA.CreateFromNfa( decision, decisionStartState );
// Retry to create a simpler DFA if analysis failed (non-LL(*),
// recursion overflow, or time out).
bool failed =
lookaheadDFA.Probe.IsNonLLStarDecision ||
lookaheadDFA.Probe.AnalysisOverflowed;
if ( failed && lookaheadDFA.OkToRetryWithK1 )
{
// set k=1 option and try again.
// First, clean up tracking stuff
decisionsWhoseDFAsUsesSynPreds.Remove( lookaheadDFA );
// TODO: clean up synPredNamesUsedInDFA also (harder)
d.blockAST.SetBlockOption( this, "k", 1 );
if ( composite.WatchNFAConversion )
{
Console.Out.Write( "trying decision " + decision +
" again with k=1; reason: " +
lookaheadDFA.ReasonForFailure );
}
lookaheadDFA = null; // make sure other memory is "free" before redoing
lookaheadDFA = DFA.CreateFromNfa( decision, decisionStartState );
}
SetLookaheadDFA( decision, lookaheadDFA );
if ( wackTempStructures )
{
foreach ( DFAState s in lookaheadDFA.UniqueStates.Values )
{
s.Reset();
}
}
// create map from line:col to decision DFA (for ANTLRWorks)
UpdateLineColumnToLookaheadDFAMap( lookaheadDFA );
if ( composite.WatchNFAConversion )
{
stopDFA = DateTime.Now;
Console.Out.WriteLine( "cost: " + lookaheadDFA.NumberOfStates +
" states, " + (int)( stopDFA - startDFA ).TotalMilliseconds + " ms" );
}
//[email protected]("after create DFA; synPredNamesUsedInDFA="+synPredNamesUsedInDFA);
return lookaheadDFA;
}
