protected ATNConfigSet ComputeStartState(ICharStream input,
ATNState p)
{
PredictionContext initialContext = PredictionContext.EMPTY;
ATNConfigSet configs = new OrderedATNConfigSet();
for (int i = 0; i < p.NumberOfTransitions; i++)
{
ATNState target = p.Transition(i).target;
LexerATNConfig c = new LexerATNConfig(target, i + 1, initialContext);
Closure(input, c, configs, false, false, false);
}
return(configs);
}
public static PredictionContext FromRuleContext(ATN atn, RuleContext outerContext)
{
if (outerContext == null)
{
outerContext = ParserRuleContext.EMPTY;
}
if (outerContext.Parent == null || outerContext == ParserRuleContext.EMPTY)
{
return(PredictionContext.EMPTY);
}
PredictionContext parent = PredictionContext.FromRuleContext(atn, outerContext.Parent);
ATNState state = atn.states[outerContext.invokingState];
RuleTransition transition = (RuleTransition)state.Transition(0);
return(parent.GetChild(transition.followState.stateNumber));
}
/// <summary>
/// Analyze the
/// <see cref="StarLoopEntryState"/>
/// states in the specified ATN to set
/// the
/// <see cref="StarLoopEntryState.isPrecedenceDecision"/>
/// field to the
/// correct value.
/// </summary>
/// <param name="atn">The ATN.</param>
protected internal virtual void MarkPrecedenceDecisions(ATN atn)
{
foreach (ATNState state in atn.states)
{
if (!(state is StarLoopEntryState))
{
continue;
}
if (atn.ruleToStartState[state.ruleIndex].isPrecedenceRule)
{
ATNState maybeLoopEndState = state.Transition(state.NumberOfTransitions - 1).target;
if (maybeLoopEndState is LoopEndState)
{
if (maybeLoopEndState.epsilonOnlyTransitions && maybeLoopEndState.Transition(0).target is RuleStopState)
{
((StarLoopEntryState)state).isPrecedenceDecision = true;
}
}
}
}
}
/// <summary>
/// Compute set of tokens that can follow
/// <paramref name="s"/>
/// in the ATN in the
/// specified
/// <paramref name="ctx"/>
/// .
/// <p/>
/// If
/// <paramref name="ctx"/>
/// is
/// <see cref="PredictionContext.EMPTY"/>
/// and
/// <paramref name="stopState"/>
/// or the end of the rule containing
/// <paramref name="s"/>
/// is reached,
/// <see cref="TokenConstants.EPSILON"/>
/// is added to the result set. If
/// <paramref name="ctx"/>
/// is not
/// <see cref="PredictionContext.EMPTY"/>
/// and
/// <paramref name="addEOF"/>
/// is
/// <see langword="true"/>
/// and
/// <paramref name="stopState"/>
/// or the end of the outermost rule is reached,
/// <see cref="TokenConstants.EOF"/>
/// is added to the result set.
/// </summary>
/// <param name="s">the ATN state.</param>
/// <param name="stopState">
/// the ATN state to stop at. This can be a
/// <see cref="BlockEndState"/>
/// to detect epsilon paths through a closure.
/// </param>
/// <param name="ctx">
/// The outer context, or
/// <see cref="PredictionContext.EMPTY"/>
/// if
/// the outer context should not be used.
/// </param>
/// <param name="look">The result lookahead set.</param>
/// <param name="lookBusy">
/// A set used for preventing epsilon closures in the ATN
/// from causing a stack overflow. Outside code should pass
/// <c>new HashSet<ATNConfig></c>
/// for this argument.
/// </param>
/// <param name="calledRuleStack">
/// A set used for preventing left recursion in the
/// ATN from causing a stack overflow. Outside code should pass
/// <c>new BitSet()</c>
/// for this argument.
/// </param>
/// <param name="seeThruPreds">
///
/// <see langword="true"/>
/// to true semantic predicates as
/// implicitly
/// <see langword="true"/>
/// and "see through them", otherwise
/// <see langword="false"/>
/// to treat semantic predicates as opaque and add
/// <see cref="HitPred"/>
/// to the
/// result if one is encountered.
/// </param>
/// <param name="addEOF">
/// Add
/// <see cref="TokenConstants.EOF"/>
/// to the result if the end of the
/// outermost context is reached. This parameter has no effect if
/// <paramref name="ctx"/>
/// is
/// <see cref="PredictionContext.EMPTY"/>
/// .
/// </param>
protected internal virtual void Look(ATNState s, ATNState stopState, PredictionContext ctx, IntervalSet look, HashSet <ATNConfig> lookBusy, BitSet calledRuleStack, bool seeThruPreds, bool addEOF)
{
// System.out.println("_LOOK("+s.stateNumber+", ctx="+ctx);
ATNConfig c = new ATNConfig(s, 0, ctx);
if (!lookBusy.Add(c))
{
return;
}
if (s == stopState)
{
if (ctx == null)
{
look.Add(TokenConstants.EPSILON);
return;
}
else if (ctx.IsEmpty && addEOF)
{
look.Add(TokenConstants.EOF);
return;
}
}
if (s is RuleStopState)
{
if (ctx == null)
{
look.Add(TokenConstants.EPSILON);
return;
}
else if (ctx.IsEmpty && addEOF)
{
look.Add(TokenConstants.EOF);
return;
}
if (ctx != PredictionContext.EMPTY)
{
for (int i = 0; i < ctx.Size; i++)
{
ATNState returnState = atn.states[ctx.GetReturnState(i)];
bool removed = calledRuleStack.Get(returnState.ruleIndex);
try
{
calledRuleStack.Clear(returnState.ruleIndex);
Look(returnState, stopState, ctx.GetParent(i), look, lookBusy, calledRuleStack, seeThruPreds, addEOF);
}
finally
{
if (removed)
{
calledRuleStack.Set(returnState.ruleIndex);
}
}
}
return;
}
}
int n = s.NumberOfTransitions;
for (int i_1 = 0; i_1 < n; i_1++)
{
Transition t = s.Transition(i_1);
if (t is RuleTransition)
{
RuleTransition ruleTransition = (RuleTransition)t;
if (calledRuleStack.Get(ruleTransition.ruleIndex))
{
continue;
}
PredictionContext newContext = SingletonPredictionContext.Create(ctx, ruleTransition.followState.stateNumber);
try
{
calledRuleStack.Set(ruleTransition.target.ruleIndex);
Look(t.target, stopState, newContext, look, lookBusy, calledRuleStack, seeThruPreds, addEOF);
}
finally
{
calledRuleStack.Clear(ruleTransition.target.ruleIndex);
}
}
else
{
if (t is AbstractPredicateTransition)
{
if (seeThruPreds)
{
Look(t.target, stopState, ctx, look, lookBusy, calledRuleStack, seeThruPreds, addEOF);
}
else
{
look.Add(HitPred);
}
}
else
{
if (t.IsEpsilon)
{
Look(t.target, stopState, ctx, look, lookBusy, calledRuleStack, seeThruPreds, addEOF);
}
else
{
if (t is WildcardTransition)
{
look.AddAll(IntervalSet.Of(TokenConstants.MinUserTokenType, atn.maxTokenType));
}
else
{
IntervalSet set = t.Label;
if (set != null)
{
if (t is NotSetTransition)
{
set = set.Complement(IntervalSet.Of(TokenConstants.MinUserTokenType, atn.maxTokenType));
}
look.AddAll(set);
}
}
}
}
}
}
}
protected internal virtual void GenerateRuleBypassTransitions(ATN atn)
{
atn.ruleToTokenType = new int[atn.ruleToStartState.Length];
for (int i_10 = 0; i_10 < atn.ruleToStartState.Length; i_10++)
{
atn.ruleToTokenType[i_10] = atn.maxTokenType + i_10 + 1;
}
for (int i_13 = 0; i_13 < atn.ruleToStartState.Length; i_13++)
{
BasicBlockStartState bypassStart = new BasicBlockStartState();
bypassStart.ruleIndex = i_13;
atn.AddState(bypassStart);
BlockEndState bypassStop = new BlockEndState();
bypassStop.ruleIndex = i_13;
atn.AddState(bypassStop);
bypassStart.endState = bypassStop;
atn.DefineDecisionState(bypassStart);
bypassStop.startState = bypassStart;
ATNState endState;
Transition excludeTransition = null;
if (atn.ruleToStartState[i_13].isPrecedenceRule)
{
// wrap from the beginning of the rule to the StarLoopEntryState
endState = null;
foreach (ATNState state_3 in atn.states)
{
if (state_3.ruleIndex != i_13)
{
continue;
}
if (!(state_3 is StarLoopEntryState))
{
continue;
}
ATNState maybeLoopEndState = state_3.Transition(state_3.NumberOfTransitions - 1).target;
if (!(maybeLoopEndState is LoopEndState))
{
continue;
}
if (maybeLoopEndState.epsilonOnlyTransitions && maybeLoopEndState.Transition(0).target is RuleStopState)
{
endState = state_3;
break;
}
}
if (endState == null)
{
throw new NotSupportedException("Couldn't identify final state of the precedence rule prefix section.");
}
excludeTransition = ((StarLoopEntryState)endState).loopBackState.Transition(0);
}
else
{
endState = atn.ruleToStopState[i_13];
}
// all non-excluded transitions that currently target end state need to target blockEnd instead
foreach (ATNState state_4 in atn.states)
{
foreach (Transition transition in state_4.transitions)
{
if (transition == excludeTransition)
{
continue;
}
if (transition.target == endState)
{
transition.target = bypassStop;
}
}
}
// all transitions leaving the rule start state need to leave blockStart instead
while (atn.ruleToStartState[i_13].NumberOfTransitions > 0)
{
Transition transition = atn.ruleToStartState[i_13].Transition(atn.ruleToStartState[i_13].NumberOfTransitions - 1);
atn.ruleToStartState[i_13].RemoveTransition(atn.ruleToStartState[i_13].NumberOfTransitions - 1);
bypassStart.AddTransition(transition);
}
// link the new states
atn.ruleToStartState[i_13].AddTransition(new EpsilonTransition(bypassStart));
bypassStop.AddTransition(new EpsilonTransition(endState));
ATNState matchState = new BasicState();
atn.AddState(matchState);
matchState.AddTransition(new AtomTransition(bypassStop, atn.ruleToTokenType[i_13]));
bypassStart.AddTransition(new EpsilonTransition(matchState));
}
if (deserializationOptions.VerifyAtn)
{
// reverify after modification
VerifyATN(atn);
}
}
/**
* Since the alternatives within any lexer decision are ordered by
* preference, this method stops pursuing the closure as soon as an accept
* state is reached. After the first accept state is reached by depth-first
* search from {@code config}, all other (potentially reachable) states for
* this rule would have a lower priority.
*
* @return {@code true} if an accept state is reached, otherwise
* {@code false}.
*/
protected bool Closure(ICharStream input, LexerATNConfig config, ATNConfigSet configs, bool currentAltReachedAcceptState, bool speculative, bool treatEofAsEpsilon)
{
if (debug)
{
ConsoleWriteLine("closure(" + config.ToString(recog, true) + ")");
}
if (config.state is RuleStopState)
{
if (debug)
{
if (recog != null)
{
ConsoleWriteLine("closure at " + recog.RuleNames[config.state.ruleIndex] + " rule stop " + config);
}
else
{
ConsoleWriteLine("closure at rule stop " + config);
}
}
if (config.context == null || config.context.HasEmptyPath)
{
if (config.context == null || config.context.IsEmpty)
{
configs.Add(config);
return(true);
}
else
{
configs.Add(new LexerATNConfig(config, config.state, PredictionContext.EMPTY));
currentAltReachedAcceptState = true;
}
}
if (config.context != null && !config.context.IsEmpty)
{
for (int i = 0; i < config.context.Size; i++)
{
if (config.context.GetReturnState(i) != PredictionContext.EMPTY_RETURN_STATE)
{
PredictionContext newContext = config.context.GetParent(i); // "pop" return state
ATNState returnState = atn.states[config.context.GetReturnState(i)];
LexerATNConfig c = new LexerATNConfig(config, returnState, newContext);
currentAltReachedAcceptState = Closure(input, c, configs, currentAltReachedAcceptState, speculative, treatEofAsEpsilon);
}
}
}
return(currentAltReachedAcceptState);
}
// optimization
if (!config.state.OnlyHasEpsilonTransitions)
{
if (!currentAltReachedAcceptState || !config.hasPassedThroughNonGreedyDecision())
{
configs.Add(config);
}
}
ATNState p = config.state;
for (int i = 0; i < p.NumberOfTransitions; i++)
{
Transition t = p.Transition(i);
LexerATNConfig c = GetEpsilonTarget(input, config, t, configs, speculative, treatEofAsEpsilon);
if (c != null)
{
currentAltReachedAcceptState = Closure(input, c, configs, currentAltReachedAcceptState, speculative, treatEofAsEpsilon);
}
}
return(currentAltReachedAcceptState);
}