private static PredictionContext AppendContext(PredictionContext context, PredictionContext suffix, PredictionContext.IdentityHashMap visited)
{
if (suffix.IsEmpty)
{
if (IsEmptyLocal(suffix))
{
if (context.HasEmpty)
{
return EmptyLocal;
}
throw new NotSupportedException("what to do here?");
}
return context;
}
if (suffix.Size != 1)
{
throw new NotSupportedException("Appending a tree suffix is not yet supported.");
}
PredictionContext result;
if (!visited.TryGetValue(context, out result))
{
if (context.IsEmpty)
{
result = suffix;
}
else
{
int parentCount = context.Size;
if (context.HasEmpty)
{
parentCount--;
}
PredictionContext[] updatedParents = new PredictionContext[parentCount];
int[] updatedReturnStates = new int[parentCount];
for (int i = 0; i < parentCount; i++)
{
updatedReturnStates[i] = context.GetReturnState(i);
}
for (int i_1 = 0; i_1 < parentCount; i_1++)
{
updatedParents[i_1] = AppendContext(context.GetParent(i_1), suffix, visited);
}
if (updatedParents.Length == 1)
{
result = new SingletonPredictionContext(updatedParents[0], updatedReturnStates[0]);
}
else
{
System.Diagnostics.Debug.Assert(updatedParents.Length > 1);
result = new Antlr4.Runtime.Atn.ArrayPredictionContext(updatedParents, updatedReturnStates);
}
if (context.HasEmpty)
{
result = PredictionContext.Join(result, suffix);
}
}
visited[context] = result;
}
return result;
}
/// <summary>
/// Compute set of tokens that can follow
/// <code>s</code>
/// in the ATN in the
/// specified
/// <code>ctx</code>
/// .
/// <p/>
/// If
/// <code>ctx</code>
/// is
/// <see cref="PredictionContext.EmptyLocal">PredictionContext.EmptyLocal</see>
/// and
/// <code>stopState</code>
/// or the end of the rule containing
/// <code>s</code>
/// is reached,
/// <see cref="TokenConstants.Epsilon"/>
/// is added to the result set. If
/// <code>ctx</code>
/// is not
/// <see cref="PredictionContext.EmptyLocal">PredictionContext.EmptyLocal</see>
/// and
/// <code>addEOF</code>
/// is
/// <code>true</code>
/// and
/// <code>stopState</code>
/// 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">BlockEndState</see>
/// to detect epsilon paths through a closure.
/// </param>
/// <param name="ctx">
/// The outer context, or
/// <see cref="PredictionContext.EmptyLocal">PredictionContext.EmptyLocal</see>
/// 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
/// <code>new HashSet<ATNConfig></code>
/// 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
/// <code>new BitSet()</code>
/// for this argument.
/// </param>
/// <param name="seeThruPreds">
///
/// <code>true</code>
/// to true semantic predicates as
/// implicitly
/// <code>true</code>
/// and "see through them", otherwise
/// <code>false</code>
/// to treat semantic predicates as opaque and add
/// <see cref="HitPred">HitPred</see>
/// 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
/// <code>ctx</code>
/// is
/// <see cref="PredictionContext.EmptyLocal">PredictionContext.EmptyLocal</see>
/// .
/// </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 = ATNConfig.Create(s, 0, ctx);
if (!lookBusy.Add(c))
{
return;
}
if (s == stopState)
{
if (PredictionContext.IsEmptyLocal(ctx))
{
look.Add(TokenConstants.Epsilon);
return;
}
else
{
if (ctx.IsEmpty && addEOF)
{
look.Add(TokenConstants.Eof);
return;
}
}
}
if (s is RuleStopState)
{
if (PredictionContext.IsEmptyLocal(ctx))
{
look.Add(TokenConstants.Epsilon);
return;
}
else
{
if (ctx.IsEmpty && addEOF)
{
look.Add(TokenConstants.Eof);
return;
}
}
for (int i = 0; i < ctx.Size; i++)
{
if (ctx.GetReturnState(i) != PredictionContext.EmptyFullStateKey)
{
ATNState returnState = atn.states[ctx.GetReturnState(i)];
// System.out.println("popping back to "+retState);
for (int j = 0; j < ctx.Size; j++)
{
bool removed = calledRuleStack.Get(returnState.ruleIndex);
try
{
calledRuleStack.Clear(returnState.ruleIndex);
Look(returnState, stopState, ctx.GetParent(j), 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.GetType() == typeof(RuleTransition))
{
if (calledRuleStack.Get(((RuleTransition)t).target.ruleIndex))
{
continue;
}
PredictionContext newContext = ctx.GetChild(((RuleTransition)t).followState.stateNumber
);
try
{
calledRuleStack.Set(((RuleTransition)t).target.ruleIndex);
Look(t.target, stopState, newContext, look, lookBusy, calledRuleStack, seeThruPreds
, addEOF);
}
finally
{
calledRuleStack.Clear(((RuleTransition)t).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.GetType() == typeof(WildcardTransition))
{
look.AddAll(IntervalSet.Of(TokenConstants.MinUserTokenType, atn.maxTokenType));
}
else
{
// System.out.println("adding "+ t);
IntervalSet set = t.Label;
if (set != null)
{
if (t is NotSetTransition)
{
set = set.Complement(IntervalSet.Of(TokenConstants.MinUserTokenType, atn.maxTokenType
));
}
look.AddAll(set);
}
}
}
}
}
}
}
private static String ToDotString(PredictionContext context)
{
StringBuilder nodes = new StringBuilder();
StringBuilder edges = new StringBuilder();
IDictionary <PredictionContext, PredictionContext> visited = new IdentityHashMap <PredictionContext, PredictionContext>();
IDictionary <PredictionContext, int> contextIds = new IdentityHashMap <PredictionContext, int>();
Stack <PredictionContext> workList = new Stack <PredictionContext>();
visited[context] = context;
contextIds[context] = contextIds.Count;
workList.Push(context);
while (workList.Count > 0)
{
PredictionContext current = workList.Pop();
nodes.Append(" s").Append(contextIds[current]).Append('[');
if (current.Size > 1)
{
nodes.Append("shape=record, ");
}
nodes.Append("label=\"");
if (current.IsEmpty)
{
nodes.Append(PredictionContext.IsEmptyLocal(current) ? '*' : '$');
}
else if (current.Size > 1)
{
for (int i = 0; i < current.Size; i++)
{
if (i > 0)
{
nodes.Append('|');
}
nodes.Append("<p").Append(i).Append('>');
if (current.GetReturnState(i) == PredictionContext.EmptyFullStateKey)
{
nodes.Append('$');
}
else if (current.GetReturnState(i) == PredictionContext.EmptyLocalStateKey)
{
nodes.Append('*');
}
}
}
else
{
nodes.Append(contextIds[current]);
}
nodes.AppendLine("\"];");
for (int i = 0; i < current.Size; i++)
{
if (current.GetReturnState(i) == PredictionContext.EmptyFullStateKey ||
current.GetReturnState(i) == PredictionContext.EmptyLocalStateKey)
{
continue;
}
if (!visited.ContainsKey(current.GetParent(i)))
{
visited[current.GetParent(i)] = current.GetParent(i);
contextIds[current.GetParent(i)] = contextIds.Count;
workList.Push(current.GetParent(i));
}
edges.Append(" s").Append(contextIds[current]);
if (current.Size > 1)
{
edges.Append(":p").Append(i);
}
edges.Append("->");
edges.Append('s').Append(contextIds[current.GetParent(i)]);
edges.Append("[label=\"").Append(current.GetReturnState(i)).Append("\"]");
edges.AppendLine(";");
}
}
StringBuilder builder = new StringBuilder();
builder.AppendLine("digraph G {");
builder.AppendLine("rankdir=LR;");
builder.Append(nodes);
builder.Append(edges);
builder.AppendLine("}");
return(builder.ToString());
}
/// <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.EmptyLocal"/>
/// 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.EmptyLocal"/>
/// 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.EmptyLocal"/>
/// 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.EmptyLocal"/>
/// .
/// </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);
}
}
}
}
}
}
}