add antlr

lib/antlr4/include/atn/ATN.h

@@ -0,0 +1,112 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "RuleContext.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC ATN {
+  public:
+    static const size_t INVALID_ALT_NUMBER = 0;
+
+    /// Used for runtime deserialization of ATNs from strings.
+    ATN();
+    ATN(ATN &&other);
+    ATN(ATNType grammarType, size_t maxTokenType);
+    virtual ~ATN();
+
+    std::vector<ATNState *> states;
+
+    /// Each subrule/rule is a decision point and we must track them so we
+    /// can go back later and build DFA predictors for them.  This includes
+    /// all the rules, subrules, optional blocks, ()+, ()* etc...
+    std::vector<DecisionState *> decisionToState;
+
+    /// Maps from rule index to starting state number.
+    std::vector<RuleStartState *> ruleToStartState;
+
+    /// Maps from rule index to stop state number.
+    std::vector<RuleStopState *> ruleToStopState;
+
+    /// The type of the ATN.
+    ATNType grammarType;
+
+    /// The maximum value for any symbol recognized by a transition in the ATN.
+    size_t maxTokenType;
+
+    /// <summary>
+    /// For lexer ATNs, this maps the rule index to the resulting token type.
+    /// For parser ATNs, this maps the rule index to the generated bypass token
+    /// type if the
+    /// <seealso cref="ATNDeserializationOptions#isGenerateRuleBypassTransitions"/>
+    /// deserialization option was specified; otherwise, this is {@code null}.
+    /// </summary>
+    std::vector<size_t> ruleToTokenType;
+
+    /// For lexer ATNs, this is an array of {@link LexerAction} objects which may
+    /// be referenced by action transitions in the ATN.
+    std::vector<Ref<LexerAction>> lexerActions;
+
+    std::vector<TokensStartState *> modeToStartState;
+
+    ATN& operator = (ATN &other) NOEXCEPT;
+    ATN& operator = (ATN &&other) NOEXCEPT;
+
+    /// <summary>
+    /// Compute the set of valid tokens that can occur starting in state {@code s}.
+    ///  If {@code ctx} is null, the set of tokens will not include what can follow
+    ///  the rule surrounding {@code s}. In other words, the set will be
+    ///  restricted to tokens reachable staying within {@code s}'s rule.
+    /// </summary>
+    virtual misc::IntervalSet nextTokens(ATNState *s, RuleContext *ctx) const;
+
+    /// <summary>
+    /// Compute the set of valid tokens that can occur starting in {@code s} and
+    /// staying in same rule. <seealso cref="Token#EPSILON"/> is in set if we reach end of
+    /// rule.
+    /// </summary>
+    virtual misc::IntervalSet const& nextTokens(ATNState *s) const;
+
+    virtual void addState(ATNState *state);
+
+    virtual void removeState(ATNState *state);
+
+    virtual int defineDecisionState(DecisionState *s);
+
+    virtual DecisionState *getDecisionState(size_t decision) const;
+
+    virtual size_t getNumberOfDecisions() const;
+
+    /// <summary>
+    /// Computes the set of input symbols which could follow ATN state number
+    /// {@code stateNumber} in the specified full {@code context}. This method
+    /// considers the complete parser context, but does not evaluate semantic
+    /// predicates (i.e. all predicates encountered during the calculation are
+    /// assumed true). If a path in the ATN exists from the starting state to the
+    /// <seealso cref="RuleStopState"/> of the outermost context without matching any
+    /// symbols, <seealso cref="Token#EOF"/> is added to the returned set.
+    /// <p/>
+    /// If {@code context} is {@code null}, it is treated as
+    /// <seealso cref="ParserRuleContext#EMPTY"/>.
+    /// </summary>
+    /// <param name="stateNumber"> the ATN state number </param>
+    /// <param name="context"> the full parse context </param>
+    /// <returns> The set of potentially valid input symbols which could follow the
+    /// specified state in the specified context. </returns>
+    /// <exception cref="IllegalArgumentException"> if the ATN does not contain a state with
+    /// number {@code stateNumber} </exception>
+    virtual misc::IntervalSet getExpectedTokens(size_t stateNumber, RuleContext *context) const;
+
+    std::string toString() const;
+
+  private:
+    mutable std::mutex _mutex;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ATNConfig.h

@@ -0,0 +1,148 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// A tuple: (ATN state, predicted alt, syntactic, semantic context).
+  ///  The syntactic context is a graph-structured stack node whose
+  ///  path(s) to the root is the rule invocation(s)
+  ///  chain used to arrive at the state.  The semantic context is
+  ///  the tree of semantic predicates encountered before reaching
+  ///  an ATN state.
+  /// </summary>
+  class ANTLR4CPP_PUBLIC ATNConfig {
+  public:
+    struct Hasher
+    {
+      size_t operator()(ATNConfig const& k) const {
+        return k.hashCode();
+      }
+    };
+
+    struct Comparer {
+      bool operator()(ATNConfig const& lhs, ATNConfig const& rhs) const {
+        return (&lhs == &rhs) || (lhs == rhs);
+      }
+    };
+
+
+    using Set = std::unordered_set<Ref<ATNConfig>, Hasher, Comparer>;
+
+    /// The ATN state associated with this configuration.
+    ATNState * state;
+
+    /// What alt (or lexer rule) is predicted by this configuration.
+    const size_t alt;
+
+    /// The stack of invoking states leading to the rule/states associated
+    /// with this config.  We track only those contexts pushed during
+    /// execution of the ATN simulator.
+    ///
+    /// Can be shared between multiple ANTConfig instances.
+    Ref<PredictionContext> context;
+
+    /**
+     * We cannot execute predicates dependent upon local context unless
+     * we know for sure we are in the correct context. Because there is
+     * no way to do this efficiently, we simply cannot evaluate
+     * dependent predicates unless we are in the rule that initially
+     * invokes the ATN simulator.
+     *
+     * <p>
+     * closure() tracks the depth of how far we dip into the outer context:
+     * depth > 0.  Note that it may not be totally accurate depth since I
+     * don't ever decrement. TODO: make it a boolean then</p>
+     *
+     * <p>
+     * For memory efficiency, the {@link #isPrecedenceFilterSuppressed} method
+     * is also backed by this field. Since the field is publicly accessible, the
+     * highest bit which would not cause the value to become negative is used to
+     * store this field. This choice minimizes the risk that code which only
+     * compares this value to 0 would be affected by the new purpose of the
+     * flag. It also ensures the performance of the existing {@link ATNConfig}
+     * constructors as well as certain operations like
+     * {@link ATNConfigSet#add(ATNConfig, DoubleKeyMap)} method are
+     * <em>completely</em> unaffected by the change.</p>
+     */
+    size_t reachesIntoOuterContext;
+
+    /// Can be shared between multiple ATNConfig instances.
+    Ref<SemanticContext> semanticContext;
+
+    ATNConfig(ATNState *state, size_t alt, Ref<PredictionContext> const& context);
+    ATNConfig(ATNState *state, size_t alt, Ref<PredictionContext> const& context, Ref<SemanticContext> const& semanticContext);
+
+    ATNConfig(Ref<ATNConfig> const& c); // dup
+    ATNConfig(Ref<ATNConfig> const& c, ATNState *state);
+    ATNConfig(Ref<ATNConfig> const& c, ATNState *state, Ref<SemanticContext> const& semanticContext);
+    ATNConfig(Ref<ATNConfig> const& c, Ref<SemanticContext> const& semanticContext);
+    ATNConfig(Ref<ATNConfig> const& c, ATNState *state, Ref<PredictionContext> const& context);
+    ATNConfig(Ref<ATNConfig> const& c, ATNState *state, Ref<PredictionContext> const& context, Ref<SemanticContext> const& semanticContext);
+
+    ATNConfig(ATNConfig const&) = default;
+    virtual ~ATNConfig();
+
+    virtual size_t hashCode() const;
+
+    /**
+     * This method gets the value of the {@link #reachesIntoOuterContext} field
+     * as it existed prior to the introduction of the
+     * {@link #isPrecedenceFilterSuppressed} method.
+     */
+    size_t getOuterContextDepth() const ;
+    bool isPrecedenceFilterSuppressed() const;
+    void setPrecedenceFilterSuppressed(bool value);
+
+    /// An ATN configuration is equal to another if both have
+    /// the same state, they predict the same alternative, and
+    /// syntactic/semantic contexts are the same.
+    bool operator == (const ATNConfig &other) const;
+    bool operator != (const ATNConfig &other) const;
+
+    virtual std::string toString();
+    std::string toString(bool showAlt);
+
+  private:
+    /**
+     * This field stores the bit mask for implementing the
+     * {@link #isPrecedenceFilterSuppressed} property as a bit within the
+     * existing {@link #reachesIntoOuterContext} field.
+     */
+    static const size_t SUPPRESS_PRECEDENCE_FILTER;
+  };
+
+} // namespace atn
+} // namespace antlr4
+
+
+// Hash function for ATNConfig.
+
+namespace std {
+  using antlr4::atn::ATNConfig;
+
+  template <> struct hash<ATNConfig>
+  {
+    size_t operator() (const ATNConfig &x) const
+    {
+      return x.hashCode();
+    }
+  };
+
+  template <> struct hash<std::vector<Ref<ATNConfig>>>
+  {
+    size_t operator() (const std::vector<Ref<ATNConfig>> &vector) const
+    {
+      std::size_t seed = 0;
+      for (auto &config : vector) {
+        seed ^= config->hashCode() + 0x9e3779b9 + (seed << 6) + (seed >> 2);
+      }
+      return seed;
+    }
+  };
+}

lib/antlr4/include/atn/ATNConfigSet.h

@@ -0,0 +1,110 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "support/BitSet.h"
+#include "atn/PredictionContext.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// Specialized set that can track info about the set, with support for combining similar configurations using a
+  /// graph-structured stack.
+  class ANTLR4CPP_PUBLIC ATNConfigSet {
+  public:
+    /// Track the elements as they are added to the set; supports get(i)
+    std::vector<Ref<ATNConfig>> configs;
+
+    // TODO: these fields make me pretty uncomfortable but nice to pack up info together, saves recomputation
+    // TODO: can we track conflicts as they are added to save scanning configs later?
+    size_t uniqueAlt;
+
+    /** Currently this is only used when we detect SLL conflict; this does
+     *  not necessarily represent the ambiguous alternatives. In fact,
+     *  I should also point out that this seems to include predicated alternatives
+     *  that have predicates that evaluate to false. Computed in computeTargetState().
+     */
+    antlrcpp::BitSet conflictingAlts;
+
+    // Used in parser and lexer. In lexer, it indicates we hit a pred
+    // while computing a closure operation.  Don't make a DFA state from this.
+    bool hasSemanticContext;
+    bool dipsIntoOuterContext;
+
+    /// Indicates that this configuration set is part of a full context
+    /// LL prediction. It will be used to determine how to merge $. With SLL
+    /// it's a wildcard whereas it is not for LL context merge.
+    const bool fullCtx;
+
+    ATNConfigSet(bool fullCtx = true);
+    ATNConfigSet(const Ref<ATNConfigSet> &old);
+
+    virtual ~ATNConfigSet();
+
+    virtual bool add(const Ref<ATNConfig> &config);
+
+    /// <summary>
+    /// Adding a new config means merging contexts with existing configs for
+    /// {@code (s, i, pi, _)}, where {@code s} is the
+    /// <seealso cref="ATNConfig#state"/>, {@code i} is the <seealso cref="ATNConfig#alt"/>, and
+    /// {@code pi} is the <seealso cref="ATNConfig#semanticContext"/>. We use
+    /// {@code (s,i,pi)} as key.
+    /// <p/>
+    /// This method updates <seealso cref="#dipsIntoOuterContext"/> and
+    /// <seealso cref="#hasSemanticContext"/> when necessary.
+    /// </summary>
+    virtual bool add(const Ref<ATNConfig> &config, PredictionContextMergeCache *mergeCache);
+
+    virtual std::vector<ATNState *> getStates();
+
+    /**
+     * Gets the complete set of represented alternatives for the configuration
+     * set.
+     *
+     * @return the set of represented alternatives in this configuration set
+     *
+     * @since 4.3
+     */
+    antlrcpp::BitSet getAlts();
+    virtual std::vector<Ref<SemanticContext>> getPredicates();
+
+    virtual Ref<ATNConfig> get(size_t i) const;
+
+    virtual void optimizeConfigs(ATNSimulator *interpreter);
+
+    bool addAll(const Ref<ATNConfigSet> &other);
+
+    bool operator == (const ATNConfigSet &other);
+    virtual size_t hashCode();
+    virtual size_t size();
+    virtual bool isEmpty();
+    virtual void clear();
+    virtual bool isReadonly();
+    virtual void setReadonly(bool readonly);
+    virtual std::string toString();
+
+  protected:
+    /// Indicates that the set of configurations is read-only. Do not
+    /// allow any code to manipulate the set; DFA states will point at
+    /// the sets and they must not change. This does not protect the other
+    /// fields; in particular, conflictingAlts is set after
+    /// we've made this readonly.
+    bool _readonly;
+
+    virtual size_t getHash(ATNConfig *c); // Hash differs depending on set type.
+
+  private:
+    size_t _cachedHashCode;
+
+    /// All configs but hashed by (s, i, _, pi) not including context. Wiped out
+    /// when we go readonly as this set becomes a DFA state.
+    std::unordered_map<size_t, ATNConfig *> _configLookup;
+
+    void InitializeInstanceFields();
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ATNDeserializationOptions.h

@@ -0,0 +1,50 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "antlr4-common.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC ATNDeserializationOptions {
+  private:
+    static ATNDeserializationOptions defaultOptions;
+
+    bool readOnly;
+    bool verifyATN;
+    bool generateRuleBypassTransitions;
+
+  public:
+    ATNDeserializationOptions();
+    ATNDeserializationOptions(ATNDeserializationOptions *options);
+    ATNDeserializationOptions(ATNDeserializationOptions const&) = default;
+    virtual ~ATNDeserializationOptions();
+    ATNDeserializationOptions& operator=(ATNDeserializationOptions const&) = default;
+
+    static const ATNDeserializationOptions& getDefaultOptions();
+
+    bool isReadOnly();
+
+    void makeReadOnly();
+
+    bool isVerifyATN();
+
+    void setVerifyATN(bool verify);
+
+    bool isGenerateRuleBypassTransitions();
+
+    void setGenerateRuleBypassTransitions(bool generate);
+
+  protected:
+    virtual void throwIfReadOnly();
+
+  private:
+    void InitializeInstanceFields();
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ATNDeserializer.h

@@ -0,0 +1,85 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerAction.h"
+#include "atn/ATNDeserializationOptions.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC ATNDeserializer {
+  public:
+    static const size_t SERIALIZED_VERSION;
+
+    /// This is the current serialized UUID.
+    // ml: defined as function to avoid the “static initialization order fiasco”.
+    static Guid SERIALIZED_UUID();
+
+    ATNDeserializer();
+    ATNDeserializer(const ATNDeserializationOptions& dso);
+    virtual ~ATNDeserializer();
+
+    static Guid toUUID(const unsigned short *data, size_t offset);
+
+    virtual ATN deserialize(const std::vector<uint16_t> &input);
+    virtual void verifyATN(const ATN &atn);
+
+    static void checkCondition(bool condition);
+    static void checkCondition(bool condition, const std::string &message);
+
+    static Transition *edgeFactory(const ATN &atn, size_t type, size_t src, size_t trg, size_t arg1, size_t arg2,
+                                   size_t arg3, const std::vector<misc::IntervalSet> &sets);
+
+    static ATNState *stateFactory(size_t type, size_t ruleIndex);
+
+  protected:
+    /// Determines if a particular serialized representation of an ATN supports
+    /// a particular feature, identified by the <seealso cref="UUID"/> used for serializing
+    /// the ATN at the time the feature was first introduced.
+    ///
+    /// <param name="feature"> The <seealso cref="UUID"/> marking the first time the feature was
+    /// supported in the serialized ATN. </param>
+    /// <param name="actualUuid"> The <seealso cref="UUID"/> of the actual serialized ATN which is
+    /// currently being deserialized. </param>
+    /// <returns> {@code true} if the {@code actualUuid} value represents a
+    /// serialized ATN at or after the feature identified by {@code feature} was
+    /// introduced; otherwise, {@code false}. </returns>
+    virtual bool isFeatureSupported(const Guid &feature, const Guid &actualUuid);
+    void markPrecedenceDecisions(const ATN &atn);
+    Ref<LexerAction> lexerActionFactory(LexerActionType type, int data1, int data2);
+
+  private:
+    /// This is the earliest supported serialized UUID.
+    static Guid BASE_SERIALIZED_UUID();
+
+    /// This UUID indicates an extension of <seealso cref="BASE_SERIALIZED_UUID"/> for the
+    /// addition of precedence predicates.
+    static Guid ADDED_PRECEDENCE_TRANSITIONS();
+
+    /**
+     * This UUID indicates an extension of ADDED_PRECEDENCE_TRANSITIONS
+     * for the addition of lexer actions encoded as a sequence of
+     * LexerAction instances.
+     */
+    static Guid ADDED_LEXER_ACTIONS();
+
+    /**
+     * This UUID indicates the serialized ATN contains two sets of
+     * IntervalSets, where the second set's values are encoded as
+     * 32-bit integers to support the full Unicode SMP range up to U+10FFFF.
+     */
+    static Guid ADDED_UNICODE_SMP();
+
+    /// This list contains all of the currently supported UUIDs, ordered by when
+    /// the feature first appeared in this branch.
+    static std::vector<Guid>& SUPPORTED_UUIDS();
+
+    ATNDeserializationOptions deserializationOptions;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ATNSerializer.h

@@ -0,0 +1,61 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC ATNSerializer {
+  public:
+    ATN *atn;
+
+    ATNSerializer(ATN *atn);
+    ATNSerializer(ATN *atn, const std::vector<std::string> &tokenNames);
+    virtual ~ATNSerializer();
+
+    /// <summary>
+    /// Serialize state descriptors, edge descriptors, and decision->state map
+    ///  into list of ints:
+    ///
+    /// 		grammar-type, (ANTLRParser.LEXER, ...)
+    ///  	max token type,
+    ///  	num states,
+    ///  	state-0-type ruleIndex, state-1-type ruleIndex, ... state-i-type
+    ///  ruleIndex optional-arg ...
+    ///  	num rules,
+    ///  	rule-1-start-state rule-1-args, rule-2-start-state  rule-2-args, ...
+    ///  	(args are token type,actionIndex in lexer else 0,0)
+    ///      num modes,
+    ///      mode-0-start-state, mode-1-start-state, ... (parser has 0 modes)
+    ///      num sets
+    ///      set-0-interval-count intervals, set-1-interval-count intervals, ...
+    ///  	num total edges,
+    ///      src, trg, edge-type, edge arg1, optional edge arg2 (present always),
+    ///      ...
+    ///      num decisions,
+    ///      decision-0-start-state, decision-1-start-state, ...
+    ///
+    ///  Convenient to pack into unsigned shorts to make as Java string.
+    /// </summary>
+    virtual std::vector<size_t> serialize();
+
+    virtual std::string decode(const std::wstring& data);
+    virtual std::string getTokenName(size_t t);
+
+    /// Used by Java target to encode short/int array as chars in string.
+    static std::wstring getSerializedAsString(ATN *atn);
+    static std::vector<size_t> getSerialized(ATN *atn);
+
+    static std::string getDecoded(ATN *atn, std::vector<std::string> &tokenNames);
+
+  private:
+    std::vector<std::string> _tokenNames;
+
+    void serializeUUID(std::vector<size_t> &data, Guid uuid);
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ATNSimulator.h

@@ -0,0 +1,87 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATN.h"
+#include "misc/IntervalSet.h"
+#include "support/CPPUtils.h"
+#include "atn/PredictionContext.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC ATNSimulator {
+  public:
+    /// Must distinguish between missing edge and edge we know leads nowhere.
+    static const Ref<dfa::DFAState> ERROR;
+    const ATN &atn;
+
+    ATNSimulator(const ATN &atn, PredictionContextCache &sharedContextCache);
+    virtual ~ATNSimulator();
+
+    virtual void reset() = 0;
+
+    /**
+     * Clear the DFA cache used by the current instance. Since the DFA cache may
+     * be shared by multiple ATN simulators, this method may affect the
+     * performance (but not accuracy) of other parsers which are being used
+     * concurrently.
+     *
+     * @throws UnsupportedOperationException if the current instance does not
+     * support clearing the DFA.
+     *
+     * @since 4.3
+     */
+    virtual void clearDFA();
+    virtual PredictionContextCache& getSharedContextCache();
+    virtual Ref<PredictionContext> getCachedContext(Ref<PredictionContext> const& context);
+
+    /// @deprecated Use <seealso cref="ATNDeserializer#deserialize"/> instead.
+    static ATN deserialize(const std::vector<uint16_t> &data);
+
+    /// @deprecated Use <seealso cref="ATNDeserializer#checkCondition(boolean)"/> instead.
+    static void checkCondition(bool condition);
+
+    /// @deprecated Use <seealso cref="ATNDeserializer#checkCondition(boolean, String)"/> instead.
+    static void checkCondition(bool condition, const std::string &message);
+
+    /// @deprecated Use <seealso cref="ATNDeserializer#edgeFactory"/> instead.
+    static Transition *edgeFactory(const ATN &atn, int type, int src, int trg, int arg1, int arg2, int arg3,
+                                   const std::vector<misc::IntervalSet> &sets);
+
+    /// @deprecated Use <seealso cref="ATNDeserializer#stateFactory"/> instead.
+    static ATNState *stateFactory(int type, int ruleIndex);
+
+  protected:
+    static antlrcpp::SingleWriteMultipleReadLock _stateLock; // Lock for DFA states.
+    static antlrcpp::SingleWriteMultipleReadLock _edgeLock; // Lock for the sparse edge map in DFA states.
+
+    /// <summary>
+    /// The context cache maps all PredictionContext objects that are equals()
+    ///  to a single cached copy. This cache is shared across all contexts
+    ///  in all ATNConfigs in all DFA states.  We rebuild each ATNConfigSet
+    ///  to use only cached nodes/graphs in addDFAState(). We don't want to
+    ///  fill this during closure() since there are lots of contexts that
+    ///  pop up but are not used ever again. It also greatly slows down closure().
+    ///  <p/>
+    ///  This cache makes a huge difference in memory and a little bit in speed.
+    ///  For the Java grammar on java.*, it dropped the memory requirements
+    ///  at the end from 25M to 16M. We don't store any of the full context
+    ///  graphs in the DFA because they are limited to local context only,
+    ///  but apparently there's a lot of repetition there as well. We optimize
+    ///  the config contexts before storing the config set in the DFA states
+    ///  by literally rebuilding them with cached subgraphs only.
+    ///  <p/>
+    ///  I tried a cache for use during closure operations, that was
+    ///  whacked after each adaptivePredict(). It cost a little bit
+    ///  more time I think and doesn't save on the overall footprint
+    ///  so it's not worth the complexity.
+    /// </summary>
+    PredictionContextCache &_sharedContextCache;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ATNState.h

@@ -0,0 +1,133 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "misc/IntervalSet.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// The following images show the relation of states and
+  /// <seealso cref="ATNState#transitions"/> for various grammar constructs.
+  ///
+  /// <ul>
+  ///
+  /// <li>Solid edges marked with an &#0949; indicate a required
+  /// <seealso cref="EpsilonTransition"/>.</li>
+  ///
+  /// <li>Dashed edges indicate locations where any transition derived from
+  /// <seealso cref="Transition"/> might appear.</li>
+  ///
+  /// <li>Dashed nodes are place holders for either a sequence of linked
+  /// <seealso cref="BasicState"/> states or the inclusion of a block representing a nested
+  /// construct in one of the forms below.</li>
+  ///
+  /// <li>Nodes showing multiple outgoing alternatives with a {@code ...} support
+  /// any number of alternatives (one or more). Nodes without the {@code ...} only
+  /// support the exact number of alternatives shown in the diagram.</li>
+  ///
+  /// </ul>
+  ///
+  /// <h2>Basic Blocks</h2>
+  ///
+  /// <h3>Rule</h3>
+  ///
+  /// <embed src="images/Rule.svg" type="image/svg+xml"/>
+  ///
+  /// <h3>Block of 1 or more alternatives</h3>
+  ///
+  /// <embed src="images/Block.svg" type="image/svg+xml"/>
+  ///
+  /// <h2>Greedy Loops</h2>
+  ///
+  /// <h3>Greedy Closure: {@code (...)*}</h3>
+  ///
+  /// <embed src="images/ClosureGreedy.svg" type="image/svg+xml"/>
+  ///
+  /// <h3>Greedy Positive Closure: {@code (...)+}</h3>
+  ///
+  /// <embed src="images/PositiveClosureGreedy.svg" type="image/svg+xml"/>
+  ///
+  /// <h3>Greedy Optional: {@code (...)?}</h3>
+  ///
+  /// <embed src="images/OptionalGreedy.svg" type="image/svg+xml"/>
+  ///
+  /// <h2>Non-Greedy Loops</h2>
+  ///
+  /// <h3>Non-Greedy Closure: {@code (...)*?}</h3>
+  ///
+  /// <embed src="images/ClosureNonGreedy.svg" type="image/svg+xml"/>
+  ///
+  /// <h3>Non-Greedy Positive Closure: {@code (...)+?}</h3>
+  ///
+  /// <embed src="images/PositiveClosureNonGreedy.svg" type="image/svg+xml"/>
+  ///
+  /// <h3>Non-Greedy Optional: {@code (...)??}</h3>
+  ///
+  /// <embed src="images/OptionalNonGreedy.svg" type="image/svg+xml"/>
+  /// </summary>
+  class ANTLR4CPP_PUBLIC ATN;
+
+  class ANTLR4CPP_PUBLIC ATNState {
+  public:
+    ATNState();
+    ATNState(ATNState const&) = delete;
+
+    virtual ~ATNState();
+
+    ATNState& operator=(ATNState const&) = delete;
+
+    static const size_t INITIAL_NUM_TRANSITIONS = 4;
+    static const size_t INVALID_STATE_NUMBER = static_cast<size_t>(-1); // std::numeric_limits<size_t>::max();
+
+    enum {
+      ATN_INVALID_TYPE = 0,
+      BASIC = 1,
+      RULE_START = 2,
+      BLOCK_START = 3,
+      PLUS_BLOCK_START = 4,
+      STAR_BLOCK_START = 5,
+      TOKEN_START = 6,
+      RULE_STOP = 7,
+      BLOCK_END = 8,
+      STAR_LOOP_BACK = 9,
+      STAR_LOOP_ENTRY = 10,
+      PLUS_LOOP_BACK = 11,
+      LOOP_END = 12
+    };
+
+    static const std::vector<std::string> serializationNames;
+
+    size_t stateNumber = INVALID_STATE_NUMBER;
+    size_t ruleIndex = 0; // at runtime, we don't have Rule objects
+    bool epsilonOnlyTransitions = false;
+
+  public:
+    virtual size_t hashCode();
+    bool operator == (const ATNState &other);
+
+    /// Track the transitions emanating from this ATN state.
+    std::vector<Transition*> transitions;
+
+    virtual bool isNonGreedyExitState();
+    virtual std::string toString() const;
+    virtual void addTransition(Transition *e);
+    virtual void addTransition(size_t index, Transition *e);
+    virtual Transition* removeTransition(size_t index);
+    virtual size_t getStateType() = 0;
+
+  private:
+    /// Used to cache lookahead during parsing, not used during construction.
+
+    misc::IntervalSet _nextTokenWithinRule;
+    std::atomic<bool> _nextTokenUpdated { false };
+
+    friend class ATN;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ATNType.h

@@ -0,0 +1,20 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "antlr4-common.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// Represents the type of recognizer an ATN applies to.
+  enum class ATNType {
+    LEXER = 0,
+    PARSER = 1,
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/AbstractPredicateTransition.h

@@ -0,0 +1,24 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/Transition.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTState;
+
+  class ANTLR4CPP_PUBLIC AbstractPredicateTransition : public Transition {
+
+  public:
+    AbstractPredicateTransition(ATNState *target);
+    ~AbstractPredicateTransition();
+
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ActionTransition.h

@@ -0,0 +1,33 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/Transition.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC ActionTransition final : public Transition {
+  public:
+    const size_t ruleIndex;
+    const size_t actionIndex;
+    const bool isCtxDependent; // e.g., $i ref in action
+
+    ActionTransition(ATNState *target, size_t ruleIndex);
+
+    ActionTransition(ATNState *target, size_t ruleIndex, size_t actionIndex, bool isCtxDependent);
+
+    virtual SerializationType getSerializationType() const override;
+
+    virtual bool isEpsilon() const override;
+
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/AmbiguityInfo.h

@@ -0,0 +1,68 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionEventInfo.h"
+#include "support/BitSet.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// This class represents profiling event information for an ambiguity.
+  /// Ambiguities are decisions where a particular input resulted in an SLL
+  /// conflict, followed by LL prediction also reaching a conflict state
+  /// (indicating a true ambiguity in the grammar).
+  ///
+  /// <para>
+  /// This event may be reported during SLL prediction in cases where the
+  /// conflicting SLL configuration set provides sufficient information to
+  /// determine that the SLL conflict is truly an ambiguity. For example, if none
+  /// of the ATN configurations in the conflicting SLL configuration set have
+  /// traversed a global follow transition (i.e.
+  /// <seealso cref="ATNConfig#reachesIntoOuterContext"/> is 0 for all configurations), then
+  /// the result of SLL prediction for that input is known to be equivalent to the
+  /// result of LL prediction for that input.</para>
+  ///
+  /// <para>
+  /// In some cases, the minimum represented alternative in the conflicting LL
+  /// configuration set is not equal to the minimum represented alternative in the
+  /// conflicting SLL configuration set. Grammars and inputs which result in this
+  /// scenario are unable to use <seealso cref="PredictionMode#SLL"/>, which in turn means
+  /// they cannot use the two-stage parsing strategy to improve parsing performance
+  /// for that input.</para>
+  /// </summary>
+  /// <seealso cref= ParserATNSimulator#reportAmbiguity </seealso>
+  /// <seealso cref= ANTLRErrorListener#reportAmbiguity
+  ///
+  /// @since 4.3 </seealso>
+  class ANTLR4CPP_PUBLIC AmbiguityInfo : public DecisionEventInfo {
+  public:
+    /// The set of alternative numbers for this decision event that lead to a valid parse.
+    antlrcpp::BitSet ambigAlts;
+
+    /// <summary>
+    /// Constructs a new instance of the <seealso cref="AmbiguityInfo"/> class with the
+    /// specified detailed ambiguity information.
+    /// </summary>
+    /// <param name="decision"> The decision number </param>
+    /// <param name="configs"> The final configuration set identifying the ambiguous
+    /// alternatives for the current input </param>
+    /// <param name="ambigAlts"> The set of alternatives in the decision that lead to a valid parse.
+    ///                  The predicted alt is the min(ambigAlts) </param>
+    /// <param name="input"> The input token stream </param>
+    /// <param name="startIndex"> The start index for the current prediction </param>
+    /// <param name="stopIndex"> The index at which the ambiguity was identified during
+    /// prediction </param>
+    /// <param name="fullCtx"> {@code true} if the ambiguity was identified during LL
+    /// prediction; otherwise, {@code false} if the ambiguity was identified
+    /// during SLL prediction </param>
+    AmbiguityInfo(size_t decision, ATNConfigSet *configs, const antlrcpp::BitSet &ambigAlts, TokenStream *input,
+                  size_t startIndex, size_t stopIndex, bool fullCtx);
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ArrayPredictionContext.h

@@ -0,0 +1,43 @@
+
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/PredictionContext.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class SingletonPredictionContext;
+
+  class ANTLR4CPP_PUBLIC ArrayPredictionContext : public PredictionContext {
+  public:
+    /// Parent can be empty only if full ctx mode and we make an array
+    /// from EMPTY and non-empty. We merge EMPTY by using null parent and
+    /// returnState == EMPTY_RETURN_STATE.
+    // Also here: we use a strong reference to our parents to avoid having them freed prematurely.
+    //            See also SinglePredictionContext.
+    const std::vector<Ref<PredictionContext>> parents;
+
+    /// Sorted for merge, no duplicates; if present, EMPTY_RETURN_STATE is always last.
+    const std::vector<size_t> returnStates;
+
+    ArrayPredictionContext(Ref<SingletonPredictionContext> const& a);
+    ArrayPredictionContext(std::vector<Ref<PredictionContext>> const& parents_, std::vector<size_t> const& returnStates);
+    virtual ~ArrayPredictionContext();
+
+    virtual bool isEmpty() const override;
+    virtual size_t size() const override;
+    virtual Ref<PredictionContext> getParent(size_t index) const override;
+    virtual size_t getReturnState(size_t index) const override;
+    bool operator == (const PredictionContext &o) const override;
+
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4
+

lib/antlr4/include/atn/AtomTransition.h

@@ -0,0 +1,30 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/Transition.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// TODO: make all transitions sets? no, should remove set edges.
+  class ANTLR4CPP_PUBLIC AtomTransition final : public Transition {
+  public:
+    /// The token type or character value; or, signifies special label.
+    const size_t _label;
+
+    AtomTransition(ATNState *target, size_t label);
+
+    virtual SerializationType getSerializationType() const override;
+
+    virtual misc::IntervalSet label() const override;
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/BasicBlockStartState.h

@@ -0,0 +1,22 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "antlr4-common.h"
+#include "atn/BlockStartState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC BasicBlockStartState final : public BlockStartState {
+
+  public:
+    virtual size_t getStateType() override;
+
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/BasicState.h

@@ -0,0 +1,21 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC BasicState final : public ATNState {
+
+  public:
+    virtual size_t getStateType() override;
+
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/BlockEndState.h

@@ -0,0 +1,24 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// Terminal node of a simple {@code (a|b|c)} block.
+  class ANTLR4CPP_PUBLIC BlockEndState final : public ATNState {
+  public:
+    BlockStartState *startState = nullptr;
+
+    BlockEndState();
+
+    virtual size_t getStateType() override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/BlockStartState.h

@@ -0,0 +1,21 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  ///  The start of a regular {@code (...)} block.
+  class ANTLR4CPP_PUBLIC BlockStartState : public DecisionState {
+  public:
+    ~BlockStartState();
+    BlockEndState *endState = nullptr;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ContextSensitivityInfo.h

@@ -0,0 +1,47 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionEventInfo.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// This class represents profiling event information for a context sensitivity.
+  /// Context sensitivities are decisions where a particular input resulted in an
+  /// SLL conflict, but LL prediction produced a single unique alternative.
+  ///
+  /// <para>
+  /// In some cases, the unique alternative identified by LL prediction is not
+  /// equal to the minimum represented alternative in the conflicting SLL
+  /// configuration set. Grammars and inputs which result in this scenario are
+  /// unable to use <seealso cref="PredictionMode#SLL"/>, which in turn means they cannot use
+  /// the two-stage parsing strategy to improve parsing performance for that
+  /// input.</para>
+  /// </summary>
+  /// <seealso cref= ParserATNSimulator#reportContextSensitivity </seealso>
+  /// <seealso cref= ANTLRErrorListener#reportContextSensitivity
+  ///
+  /// @since 4.3 </seealso>
+  class ANTLR4CPP_PUBLIC ContextSensitivityInfo : public DecisionEventInfo {
+  public:
+    /// <summary>
+    /// Constructs a new instance of the <seealso cref="ContextSensitivityInfo"/> class
+    /// with the specified detailed context sensitivity information.
+    /// </summary>
+    /// <param name="decision"> The decision number </param>
+    /// <param name="configs"> The final configuration set containing the unique
+    /// alternative identified by full-context prediction </param>
+    /// <param name="input"> The input token stream </param>
+    /// <param name="startIndex"> The start index for the current prediction </param>
+    /// <param name="stopIndex"> The index at which the context sensitivity was
+    /// identified during full-context prediction </param>
+    ContextSensitivityInfo(size_t decision, ATNConfigSet *configs, TokenStream *input, size_t startIndex, size_t stopIndex);
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/DecisionEventInfo.h

@@ -0,0 +1,70 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "antlr4-common.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// This is the base class for gathering detailed information about prediction
+  /// events which occur during parsing.
+  ///
+  /// Note that we could record the parser call stack at the time this event
+  /// occurred but in the presence of left recursive rules, the stack is kind of
+  /// meaningless. It's better to look at the individual configurations for their
+  /// individual stacks. Of course that is a <seealso cref="PredictionContext"/> object
+  /// not a parse tree node and so it does not have information about the extent
+  /// (start...stop) of the various subtrees. Examining the stack tops of all
+  /// configurations provide the return states for the rule invocations.
+  /// From there you can get the enclosing rule.
+  ///
+  /// @since 4.3
+  /// </summary>
+  class ANTLR4CPP_PUBLIC DecisionEventInfo {
+  public:
+    /// <summary>
+    /// The invoked decision number which this event is related to.
+    /// </summary>
+    /// <seealso cref= ATN#decisionToState </seealso>
+    const size_t decision;
+
+    /// <summary>
+    /// The configuration set containing additional information relevant to the
+    /// prediction state when the current event occurred, or {@code null} if no
+    /// additional information is relevant or available.
+    /// </summary>
+    const ATNConfigSet *configs;
+
+    /// <summary>
+    /// The input token stream which is being parsed.
+    /// </summary>
+    const TokenStream *input;
+
+    /// <summary>
+    /// The token index in the input stream at which the current prediction was
+    /// originally invoked.
+    /// </summary>
+    const size_t startIndex;
+
+    /// <summary>
+    /// The token index in the input stream at which the current event occurred.
+    /// </summary>
+    const size_t stopIndex;
+
+    /// <summary>
+    /// {@code true} if the current event occurred during LL prediction;
+    /// otherwise, {@code false} if the input occurred during SLL prediction.
+    /// </summary>
+    const bool fullCtx;
+
+    DecisionEventInfo(size_t decision, ATNConfigSet *configs, TokenStream *input, size_t startIndex,
+                      size_t stopIndex, bool fullCtx);
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/DecisionInfo.h

@@ -0,0 +1,227 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ContextSensitivityInfo.h"
+#include "atn/AmbiguityInfo.h"
+#include "atn/PredicateEvalInfo.h"
+#include "atn/ErrorInfo.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class LookaheadEventInfo;
+
+  /// <summary>
+  /// This class contains profiling gathered for a particular decision.
+  ///
+  /// <para>
+  /// Parsing performance in ANTLR 4 is heavily influenced by both static factors
+  /// (e.g. the form of the rules in the grammar) and dynamic factors (e.g. the
+  /// choice of input and the state of the DFA cache at the time profiling
+  /// operations are started). For best results, gather and use aggregate
+  /// statistics from a large sample of inputs representing the inputs expected in
+  /// production before using the results to make changes in the grammar.</para>
+  ///
+  /// @since 4.3
+  /// </summary>
+  class ANTLR4CPP_PUBLIC DecisionInfo {
+  public:
+    /// <summary>
+    /// The decision number, which is an index into <seealso cref="ATN#decisionToState"/>.
+    /// </summary>
+    const size_t decision;
+
+    /// <summary>
+    /// The total number of times <seealso cref="ParserATNSimulator#adaptivePredict"/> was
+    /// invoked for this decision.
+    /// </summary>
+    long long invocations = 0;
+
+    /// <summary>
+    /// The total time spent in <seealso cref="ParserATNSimulator#adaptivePredict"/> for
+    /// this decision, in nanoseconds.
+    ///
+    /// <para>
+    /// The value of this field contains the sum of differential results obtained
+    /// by <seealso cref="System#nanoTime()"/>, and is not adjusted to compensate for JIT
+    /// and/or garbage collection overhead. For best accuracy, use a modern JVM
+    /// implementation that provides precise results from
+    /// <seealso cref="System#nanoTime()"/>, and perform profiling in a separate process
+    /// which is warmed up by parsing the input prior to profiling. If desired,
+    /// call <seealso cref="ATNSimulator#clearDFA"/> to reset the DFA cache to its initial
+    /// state before starting the profiling measurement pass.</para>
+    /// </summary>
+    long long timeInPrediction = 0;
+
+    /// <summary>
+    /// The sum of the lookahead required for SLL prediction for this decision.
+    /// Note that SLL prediction is used before LL prediction for performance
+    /// reasons even when <seealso cref="PredictionMode#LL"/> or
+    /// <seealso cref="PredictionMode#LL_EXACT_AMBIG_DETECTION"/> is used.
+    /// </summary>
+    long long SLL_TotalLook = 0;
+
+    /// <summary>
+    /// Gets the minimum lookahead required for any single SLL prediction to
+    /// complete for this decision, by reaching a unique prediction, reaching an
+    /// SLL conflict state, or encountering a syntax error.
+    /// </summary>
+    long long SLL_MinLook = 0;
+
+    /// <summary>
+    /// Gets the maximum lookahead required for any single SLL prediction to
+    /// complete for this decision, by reaching a unique prediction, reaching an
+    /// SLL conflict state, or encountering a syntax error.
+    /// </summary>
+    long long SLL_MaxLook = 0;
+
+    /// Gets the <seealso cref="LookaheadEventInfo"/> associated with the event where the
+    /// <seealso cref="#SLL_MaxLook"/> value was set.
+    Ref<LookaheadEventInfo> SLL_MaxLookEvent;
+
+    /// <summary>
+    /// The sum of the lookahead required for LL prediction for this decision.
+    /// Note that LL prediction is only used when SLL prediction reaches a
+    /// conflict state.
+    /// </summary>
+    long long LL_TotalLook = 0;
+
+    /// <summary>
+    /// Gets the minimum lookahead required for any single LL prediction to
+    /// complete for this decision. An LL prediction completes when the algorithm
+    /// reaches a unique prediction, a conflict state (for
+    /// <seealso cref="PredictionMode#LL"/>, an ambiguity state (for
+    /// <seealso cref="PredictionMode#LL_EXACT_AMBIG_DETECTION"/>, or a syntax error.
+    /// </summary>
+    long long LL_MinLook = 0;
+
+    /// <summary>
+    /// Gets the maximum lookahead required for any single LL prediction to
+    /// complete for this decision. An LL prediction completes when the algorithm
+    /// reaches a unique prediction, a conflict state (for
+    /// <seealso cref="PredictionMode#LL"/>, an ambiguity state (for
+    /// <seealso cref="PredictionMode#LL_EXACT_AMBIG_DETECTION"/>, or a syntax error.
+    /// </summary>
+    long long LL_MaxLook = 0;
+
+    /// <summary>
+    /// Gets the <seealso cref="LookaheadEventInfo"/> associated with the event where the
+    /// <seealso cref="#LL_MaxLook"/> value was set.
+    /// </summary>
+    Ref<LookaheadEventInfo> LL_MaxLookEvent;
+
+    /// <summary>
+    /// A collection of <seealso cref="ContextSensitivityInfo"/> instances describing the
+    /// context sensitivities encountered during LL prediction for this decision.
+    /// </summary>
+    /// <seealso cref= ContextSensitivityInfo </seealso>
+    std::vector<ContextSensitivityInfo> contextSensitivities;
+
+    /// <summary>
+    /// A collection of <seealso cref="ErrorInfo"/> instances describing the parse errors
+    /// identified during calls to <seealso cref="ParserATNSimulator#adaptivePredict"/> for
+    /// this decision.
+    /// </summary>
+    /// <seealso cref= ErrorInfo </seealso>
+    std::vector<ErrorInfo> errors;
+
+    /// <summary>
+    /// A collection of <seealso cref="AmbiguityInfo"/> instances describing the
+    /// ambiguities encountered during LL prediction for this decision.
+    /// </summary>
+    /// <seealso cref= AmbiguityInfo </seealso>
+    std::vector<AmbiguityInfo> ambiguities;
+
+    /// <summary>
+    /// A collection of <seealso cref="PredicateEvalInfo"/> instances describing the
+    /// results of evaluating individual predicates during prediction for this
+    /// decision.
+    /// </summary>
+    /// <seealso cref= PredicateEvalInfo </seealso>
+    std::vector<PredicateEvalInfo> predicateEvals;
+
+    /// <summary>
+    /// The total number of ATN transitions required during SLL prediction for
+    /// this decision. An ATN transition is determined by the number of times the
+    /// DFA does not contain an edge that is required for prediction, resulting
+    /// in on-the-fly computation of that edge.
+    ///
+    /// <para>
+    /// If DFA caching of SLL transitions is employed by the implementation, ATN
+    /// computation may cache the computed edge for efficient lookup during
+    /// future parsing of this decision. Otherwise, the SLL parsing algorithm
+    /// will use ATN transitions exclusively.</para>
+    /// </summary>
+    /// <seealso cref= #SLL_ATNTransitions </seealso>
+    /// <seealso cref= ParserATNSimulator#computeTargetState </seealso>
+    /// <seealso cref= LexerATNSimulator#computeTargetState </seealso>
+    long long SLL_ATNTransitions = 0;
+
+    /// <summary>
+    /// The total number of DFA transitions required during SLL prediction for
+    /// this decision.
+    ///
+    /// <para>If the ATN simulator implementation does not use DFA caching for SLL
+    /// transitions, this value will be 0.</para>
+    /// </summary>
+    /// <seealso cref= ParserATNSimulator#getExistingTargetState </seealso>
+    /// <seealso cref= LexerATNSimulator#getExistingTargetState </seealso>
+    long long SLL_DFATransitions = 0;
+
+    /// <summary>
+    /// Gets the total number of times SLL prediction completed in a conflict
+    /// state, resulting in fallback to LL prediction.
+    ///
+    /// <para>Note that this value is not related to whether or not
+    /// <seealso cref="PredictionMode#SLL"/> may be used successfully with a particular
+    /// grammar. If the ambiguity resolution algorithm applied to the SLL
+    /// conflicts for this decision produce the same result as LL prediction for
+    /// this decision, <seealso cref="PredictionMode#SLL"/> would produce the same overall
+    /// parsing result as <seealso cref="PredictionMode#LL"/>.</para>
+    /// </summary>
+    long long LL_Fallback = 0;
+
+    /// <summary>
+    /// The total number of ATN transitions required during LL prediction for
+    /// this decision. An ATN transition is determined by the number of times the
+    /// DFA does not contain an edge that is required for prediction, resulting
+    /// in on-the-fly computation of that edge.
+    ///
+    /// <para>
+    /// If DFA caching of LL transitions is employed by the implementation, ATN
+    /// computation may cache the computed edge for efficient lookup during
+    /// future parsing of this decision. Otherwise, the LL parsing algorithm will
+    /// use ATN transitions exclusively.</para>
+    /// </summary>
+    /// <seealso cref= #LL_DFATransitions </seealso>
+    /// <seealso cref= ParserATNSimulator#computeTargetState </seealso>
+    /// <seealso cref= LexerATNSimulator#computeTargetState </seealso>
+    long long LL_ATNTransitions = 0;
+
+    /// <summary>
+    /// The total number of DFA transitions required during LL prediction for
+    /// this decision.
+    ///
+    /// <para>If the ATN simulator implementation does not use DFA caching for LL
+    /// transitions, this value will be 0.</para>
+    /// </summary>
+    /// <seealso cref= ParserATNSimulator#getExistingTargetState </seealso>
+    /// <seealso cref= LexerATNSimulator#getExistingTargetState </seealso>
+    long long LL_DFATransitions = 0;
+
+    /// <summary>
+    /// Constructs a new instance of the <seealso cref="DecisionInfo"/> class to contain
+    /// statistics for a particular decision.
+    /// </summary>
+    /// <param name="decision"> The decision number </param>
+    DecisionInfo(size_t decision);
+
+    std::string toString() const;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/DecisionState.h

@@ -0,0 +1,30 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC DecisionState : public ATNState {
+  public:
+    int decision;
+    bool nonGreedy;
+
+  private:
+    void InitializeInstanceFields();
+
+  public:
+    DecisionState() {
+      InitializeInstanceFields();
+    }
+
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/EmptyPredictionContext.h

@@ -0,0 +1,27 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/SingletonPredictionContext.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC EmptyPredictionContext : public SingletonPredictionContext {
+  public:
+    EmptyPredictionContext();
+
+    virtual bool isEmpty() const override;
+    virtual size_t size() const override;
+    virtual Ref<PredictionContext> getParent(size_t index) const override;
+    virtual size_t getReturnState(size_t index) const override;
+    virtual std::string toString() const override;
+
+    virtual bool operator == (const PredictionContext &o) const override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/EpsilonTransition.h

@@ -0,0 +1,39 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/Transition.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC EpsilonTransition final : public Transition {
+  public:
+    EpsilonTransition(ATNState *target);
+    EpsilonTransition(ATNState *target, size_t outermostPrecedenceReturn);
+
+    /**
+     * @return the rule index of a precedence rule for which this transition is
+     * returning from, where the precedence value is 0; otherwise, INVALID_INDEX.
+     *
+     * @see ATNConfig#isPrecedenceFilterSuppressed()
+     * @see ParserATNSimulator#applyPrecedenceFilter(ATNConfigSet)
+     * @since 4.4.1
+     */
+    size_t outermostPrecedenceReturn();
+    virtual SerializationType getSerializationType() const override;
+
+    virtual bool isEpsilon() const override;
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+
+    virtual std::string toString() const override;
+
+  private:
+    const size_t _outermostPrecedenceReturn; // A rule index.
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ErrorInfo.h

@@ -0,0 +1,43 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionEventInfo.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// This class represents profiling event information for a syntax error
+  /// identified during prediction. Syntax errors occur when the prediction
+  /// algorithm is unable to identify an alternative which would lead to a
+  /// successful parse.
+  /// </summary>
+  /// <seealso cref= Parser#notifyErrorListeners(Token, String, RecognitionException) </seealso>
+  /// <seealso cref= ANTLRErrorListener#syntaxError
+  ///
+  /// @since 4.3 </seealso>
+  class ANTLR4CPP_PUBLIC ErrorInfo : public DecisionEventInfo {
+  public:
+    /// <summary>
+    /// Constructs a new instance of the <seealso cref="ErrorInfo"/> class with the
+    /// specified detailed syntax error information.
+    /// </summary>
+    /// <param name="decision"> The decision number </param>
+    /// <param name="configs"> The final configuration set reached during prediction
+    /// prior to reaching the <seealso cref="ATNSimulator#ERROR"/> state </param>
+    /// <param name="input"> The input token stream </param>
+    /// <param name="startIndex"> The start index for the current prediction </param>
+    /// <param name="stopIndex"> The index at which the syntax error was identified </param>
+    /// <param name="fullCtx"> {@code true} if the syntax error was identified during LL
+    /// prediction; otherwise, {@code false} if the syntax error was identified
+    /// during SLL prediction </param>
+    ErrorInfo(size_t decision, ATNConfigSet *configs, TokenStream *input, size_t startIndex, size_t stopIndex,
+              bool fullCtx);
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LL1Analyzer.h

@@ -0,0 +1,109 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "Token.h"
+#include "support/BitSet.h"
+#include "atn/PredictionContext.h"
+#include "atn/ATNConfig.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC LL1Analyzer {
+  public:
+    /// Special value added to the lookahead sets to indicate that we hit
+    ///  a predicate during analysis if {@code seeThruPreds==false}.
+    static const size_t HIT_PRED = Token::INVALID_TYPE;
+
+    const atn::ATN &_atn;
+
+    LL1Analyzer(const atn::ATN &atn);
+    virtual ~LL1Analyzer();
+
+    /// <summary>
+    /// Calculates the SLL(1) expected lookahead set for each outgoing transition
+    /// of an <seealso cref="ATNState"/>. The returned array has one element for each
+    /// outgoing transition in {@code s}. If the closure from transition
+    /// <em>i</em> leads to a semantic predicate before matching a symbol, the
+    /// element at index <em>i</em> of the result will be {@code null}.
+    /// </summary>
+    /// <param name="s"> the ATN state </param>
+    /// <returns> the expected symbols for each outgoing transition of {@code s}. </returns>
+    virtual std::vector<misc::IntervalSet> getDecisionLookahead(ATNState *s) const;
+
+    /// <summary>
+    /// Compute set of tokens that can follow {@code s} in the ATN in the
+    /// specified {@code ctx}.
+    /// <p/>
+    /// If {@code ctx} is {@code null} and the end of the rule containing
+    /// {@code s} is reached, <seealso cref="Token#EPSILON"/> is added to the result set.
+    /// If {@code ctx} is not {@code null} and the end of the outermost rule is
+    /// reached, <seealso cref="Token#EOF"/> is added to the result set.
+    /// </summary>
+    /// <param name="s"> the ATN state </param>
+    /// <param name="ctx"> the complete parser context, or {@code null} if the context
+    /// should be ignored
+    /// </param>
+    /// <returns> The set of tokens that can follow {@code s} in the ATN in the
+    /// specified {@code ctx}. </returns>
+    virtual misc::IntervalSet LOOK(ATNState *s, RuleContext *ctx) const;
+
+    /// <summary>
+    /// Compute set of tokens that can follow {@code s} in the ATN in the
+    /// specified {@code ctx}.
+    /// <p/>
+    /// If {@code ctx} is {@code null} and the end of the rule containing
+    /// {@code s} is reached, <seealso cref="Token#EPSILON"/> is added to the result set.
+    /// If {@code ctx} is not {@code null} and the end of the outermost rule is
+    /// reached, <seealso cref="Token#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
+    /// <seealso cref="BlockEndState"/> to detect epsilon paths through a closure. </param>
+    /// <param name="ctx"> the complete parser context, or {@code null} if the context
+    /// should be ignored
+    /// </param>
+    /// <returns> The set of tokens that can follow {@code s} in the ATN in the
+    /// specified {@code ctx}. </returns>
+    virtual misc::IntervalSet LOOK(ATNState *s, ATNState *stopState, RuleContext *ctx) const;
+
+    /// <summary>
+    /// Compute set of tokens that can follow {@code s} in the ATN in the
+    /// specified {@code ctx}.
+    /// <p/>
+    /// If {@code ctx} is {@code null} and {@code stopState} or the end of the
+    /// rule containing {@code s} is reached, <seealso cref="Token#EPSILON"/> is added to
+    /// the result set. If {@code ctx} is not {@code null} and {@code addEOF} is
+    /// {@code true} and {@code stopState} or the end of the outermost rule is
+    /// reached, <seealso cref="Token#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
+    /// <seealso cref="BlockEndState"/> to detect epsilon paths through a closure. </param>
+    /// <param name="ctx"> The outer context, or {@code null} 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>} 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()} for this argument. </param>
+    /// <param name="seeThruPreds"> {@code true} to true semantic predicates as
+    /// implicitly {@code true} and "see through them", otherwise {@code false}
+    /// to treat semantic predicates as opaque and add <seealso cref="#HIT_PRED"/> to the
+    /// result if one is encountered. </param>
+    /// <param name="addEOF"> Add <seealso cref="Token#EOF"/> to the result if the end of the
+    /// outermost context is reached. This parameter has no effect if {@code ctx}
+    /// is {@code null}. </param>
+  protected:
+    virtual void _LOOK(ATNState *s, ATNState *stopState, Ref<PredictionContext> const& ctx, misc::IntervalSet &look,
+      ATNConfig::Set &lookBusy, antlrcpp::BitSet &calledRuleStack, bool seeThruPreds, bool addEOF) const;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerATNConfig.h

@@ -0,0 +1,44 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNConfig.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC LexerATNConfig : public ATNConfig {
+  public:
+    LexerATNConfig(ATNState *state, int alt, Ref<PredictionContext> const& context);
+    LexerATNConfig(ATNState *state, int alt, Ref<PredictionContext> const& context, Ref<LexerActionExecutor> const& lexerActionExecutor);
+
+    LexerATNConfig(Ref<LexerATNConfig> const& c, ATNState *state);
+    LexerATNConfig(Ref<LexerATNConfig> const& c, ATNState *state, Ref<LexerActionExecutor> const& lexerActionExecutor);
+    LexerATNConfig(Ref<LexerATNConfig> const& c, ATNState *state, Ref<PredictionContext> const& context);
+
+    /**
+     * Gets the {@link LexerActionExecutor} capable of executing the embedded
+     * action(s) for the current configuration.
+     */
+    Ref<LexerActionExecutor> getLexerActionExecutor() const;
+    bool hasPassedThroughNonGreedyDecision();
+
+    virtual size_t hashCode() const override;
+
+    bool operator == (const LexerATNConfig& other) const;
+
+  private:
+    /**
+     * This is the backing field for {@link #getLexerActionExecutor}.
+     */
+    const Ref<LexerActionExecutor> _lexerActionExecutor;
+    const bool _passedThroughNonGreedyDecision;
+
+    static bool checkNonGreedyDecision(Ref<LexerATNConfig> const& source, ATNState *target);
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerATNSimulator.h

@@ -0,0 +1,210 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNSimulator.h"
+#include "atn/LexerATNConfig.h"
+#include "atn/ATNConfigSet.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// "dup" of ParserInterpreter
+  class ANTLR4CPP_PUBLIC LexerATNSimulator : public ATNSimulator {
+  protected:
+    class SimState {
+    public:
+      virtual ~SimState();
+
+    protected:
+      size_t index;
+      size_t line;
+      size_t charPos;
+      dfa::DFAState *dfaState;
+      virtual void reset();
+      friend class LexerATNSimulator;
+
+    private:
+      void InitializeInstanceFields();
+
+    public:
+      SimState() {
+        InitializeInstanceFields();
+      }
+    };
+
+
+  public:
+    static const size_t MIN_DFA_EDGE = 0;
+    static const size_t MAX_DFA_EDGE = 127; // forces unicode to stay in ATN
+
+  protected:
+    /// <summary>
+    /// When we hit an accept state in either the DFA or the ATN, we
+    ///  have to notify the character stream to start buffering characters
+    ///  via <seealso cref="IntStream#mark"/> and record the current state. The current sim state
+    ///  includes the current index into the input, the current line,
+    ///  and current character position in that line. Note that the Lexer is
+    ///  tracking the starting line and characterization of the token. These
+    ///  variables track the "state" of the simulator when it hits an accept state.
+    /// <p/>
+    ///  We track these variables separately for the DFA and ATN simulation
+    ///  because the DFA simulation often has to fail over to the ATN
+    ///  simulation. If the ATN simulation fails, we need the DFA to fall
+    ///  back to its previously accepted state, if any. If the ATN succeeds,
+    ///  then the ATN does the accept and the DFA simulator that invoked it
+    ///  can simply return the predicted token type.
+    /// </summary>
+    Lexer *const _recog;
+
+    /// The current token's starting index into the character stream.
+    ///  Shared across DFA to ATN simulation in case the ATN fails and the
+    ///  DFA did not have a previous accept state. In this case, we use the
+    ///  ATN-generated exception object.
+    size_t _startIndex;
+
+    /// line number 1..n within the input.
+    size_t _line;
+
+    /// The index of the character relative to the beginning of the line 0..n-1.
+    size_t _charPositionInLine;
+
+  public:
+    std::vector<dfa::DFA> &_decisionToDFA;
+
+  protected:
+    size_t _mode;
+
+    /// Used during DFA/ATN exec to record the most recent accept configuration info.
+    SimState _prevAccept;
+
+  public:
+    static int match_calls;
+
+    LexerATNSimulator(const ATN &atn, std::vector<dfa::DFA> &decisionToDFA, PredictionContextCache &sharedContextCache);
+    LexerATNSimulator(Lexer *recog, const ATN &atn, std::vector<dfa::DFA> &decisionToDFA, PredictionContextCache &sharedContextCache);
+    virtual ~LexerATNSimulator () {}
+
+    virtual void copyState(LexerATNSimulator *simulator);
+    virtual size_t match(CharStream *input, size_t mode);
+    virtual void reset() override;
+
+    virtual void clearDFA() override;
+
+  protected:
+    virtual size_t matchATN(CharStream *input);
+    virtual size_t execATN(CharStream *input, dfa::DFAState *ds0);
+
+    /// <summary>
+    /// Get an existing target state for an edge in the DFA. If the target state
+    /// for the edge has not yet been computed or is otherwise not available,
+    /// this method returns {@code null}.
+    /// </summary>
+    /// <param name="s"> The current DFA state </param>
+    /// <param name="t"> The next input symbol </param>
+    /// <returns> The existing target DFA state for the given input symbol
+    /// {@code t}, or {@code null} if the target state for this edge is not
+    /// already cached </returns>
+    virtual dfa::DFAState *getExistingTargetState(dfa::DFAState *s, size_t t);
+
+    /// <summary>
+    /// Compute a target state for an edge in the DFA, and attempt to add the
+    /// computed state and corresponding edge to the DFA.
+    /// </summary>
+    /// <param name="input"> The input stream </param>
+    /// <param name="s"> The current DFA state </param>
+    /// <param name="t"> The next input symbol
+    /// </param>
+    /// <returns> The computed target DFA state for the given input symbol
+    /// {@code t}. If {@code t} does not lead to a valid DFA state, this method
+    /// returns <seealso cref="#ERROR"/>. </returns>
+    virtual dfa::DFAState *computeTargetState(CharStream *input, dfa::DFAState *s, size_t t);
+
+    virtual size_t failOrAccept(CharStream *input, ATNConfigSet *reach, size_t t);
+
+    /// <summary>
+    /// Given a starting configuration set, figure out all ATN configurations
+    ///  we can reach upon input {@code t}. Parameter {@code reach} is a return
+    ///  parameter.
+    /// </summary>
+    void getReachableConfigSet(CharStream *input, ATNConfigSet *closure_, // closure_ as we have a closure() already
+                               ATNConfigSet *reach, size_t t);
+
+    virtual void accept(CharStream *input, const Ref<LexerActionExecutor> &lexerActionExecutor, size_t startIndex, size_t index,
+                        size_t line, size_t charPos);
+
+    virtual ATNState *getReachableTarget(Transition *trans, size_t t);
+
+    virtual std::unique_ptr<ATNConfigSet> computeStartState(CharStream *input, ATNState *p);
+
+    /// <summary>
+    /// 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.
+    /// </summary>
+    /// <returns> {@code true} if an accept state is reached, otherwise
+    /// {@code false}. </returns>
+    virtual bool closure(CharStream *input, const Ref<LexerATNConfig> &config, ATNConfigSet *configs,
+                         bool currentAltReachedAcceptState, bool speculative, bool treatEofAsEpsilon);
+
+    // side-effect: can alter configs.hasSemanticContext
+    virtual Ref<LexerATNConfig> getEpsilonTarget(CharStream *input, const Ref<LexerATNConfig> &config, Transition *t,
+      ATNConfigSet *configs, bool speculative, bool treatEofAsEpsilon);
+
+    /// <summary>
+    /// Evaluate a predicate specified in the lexer.
+    /// <p/>
+    /// If {@code speculative} is {@code true}, this method was called before
+    /// <seealso cref="#consume"/> for the matched character. This method should call
+    /// <seealso cref="#consume"/> before evaluating the predicate to ensure position
+    /// sensitive values, including <seealso cref="Lexer#getText"/>, <seealso cref="Lexer#getLine"/>,
+    /// and <seealso cref="Lexer#getCharPositionInLine"/>, properly reflect the current
+    /// lexer state. This method should restore {@code input} and the simulator
+    /// to the original state before returning (i.e. undo the actions made by the
+    /// call to <seealso cref="#consume"/>.
+    /// </summary>
+    /// <param name="input"> The input stream. </param>
+    /// <param name="ruleIndex"> The rule containing the predicate. </param>
+    /// <param name="predIndex"> The index of the predicate within the rule. </param>
+    /// <param name="speculative"> {@code true} if the current index in {@code input} is
+    /// one character before the predicate's location.
+    /// </param>
+    /// <returns> {@code true} if the specified predicate evaluates to
+    /// {@code true}. </returns>
+    virtual bool evaluatePredicate(CharStream *input, size_t ruleIndex, size_t predIndex, bool speculative);
+
+    virtual void captureSimState(CharStream *input, dfa::DFAState *dfaState);
+    virtual dfa::DFAState* addDFAEdge(dfa::DFAState *from, size_t t, ATNConfigSet *q);
+    virtual void addDFAEdge(dfa::DFAState *p, size_t t, dfa::DFAState *q);
+
+    /// <summary>
+    /// Add a new DFA state if there isn't one with this set of
+    /// configurations already. This method also detects the first
+    /// configuration containing an ATN rule stop state. Later, when
+    /// traversing the DFA, we will know which rule to accept.
+    /// </summary>
+    virtual dfa::DFAState *addDFAState(ATNConfigSet *configs);
+
+  public:
+    dfa::DFA& getDFA(size_t mode);
+
+    /// Get the text matched so far for the current token.
+    virtual std::string getText(CharStream *input);
+    virtual size_t getLine() const;
+    virtual void setLine(size_t line);
+    virtual size_t getCharPositionInLine();
+    virtual void setCharPositionInLine(size_t charPositionInLine);
+    virtual void consume(CharStream *input);
+    virtual std::string getTokenName(size_t t);
+
+  private:
+    void InitializeInstanceFields();
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerAction.h

@@ -0,0 +1,66 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerActionType.h"
+#include "antlr4-common.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// Represents a single action which can be executed following the successful
+  /// match of a lexer rule. Lexer actions are used for both embedded action syntax
+  /// and ANTLR 4's new lexer command syntax.
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  class ANTLR4CPP_PUBLIC LexerAction {
+  public:
+    virtual ~LexerAction();
+
+    /// <summary>
+    /// Gets the serialization type of the lexer action.
+    /// </summary>
+    /// <returns> The serialization type of the lexer action. </returns>
+    virtual LexerActionType getActionType() const = 0;
+
+    /// <summary>
+    /// Gets whether the lexer action is position-dependent. Position-dependent
+    /// actions may have different semantics depending on the <seealso cref="CharStream"/>
+    /// index at the time the action is executed.
+    ///
+    /// <para>Many lexer commands, including {@code type}, {@code skip}, and
+    /// {@code more}, do not check the input index during their execution.
+    /// Actions like this are position-independent, and may be stored more
+    /// efficiently as part of the <seealso cref="LexerATNConfig#lexerActionExecutor"/>.</para>
+    /// </summary>
+    /// <returns> {@code true} if the lexer action semantics can be affected by the
+    /// position of the input <seealso cref="CharStream"/> at the time it is executed;
+    /// otherwise, {@code false}. </returns>
+    virtual bool isPositionDependent() const = 0;
+
+    /// <summary>
+    /// Execute the lexer action in the context of the specified <seealso cref="Lexer"/>.
+    ///
+    /// <para>For position-dependent actions, the input stream must already be
+    /// positioned correctly prior to calling this method.</para>
+    /// </summary>
+    /// <param name="lexer"> The lexer instance. </param>
+    virtual void execute(Lexer *lexer) = 0;
+
+    virtual size_t hashCode() const = 0;
+    virtual bool operator == (const LexerAction &obj) const = 0;
+    virtual bool operator != (const LexerAction &obj) const {
+      return !(*this == obj);
+    }
+
+    virtual std::string toString() const = 0;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerActionExecutor.h

@@ -0,0 +1,115 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "CharStream.h"
+#include "atn/LexerAction.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// Represents an executor for a sequence of lexer actions which traversed during
+  /// the matching operation of a lexer rule (token).
+  ///
+  /// <para>The executor tracks position information for position-dependent lexer actions
+  /// efficiently, ensuring that actions appearing only at the end of the rule do
+  /// not cause bloating of the <seealso cref="DFA"/> created for the lexer.</para>
+  class ANTLR4CPP_PUBLIC LexerActionExecutor : public std::enable_shared_from_this<LexerActionExecutor> {
+  public:
+    /// <summary>
+    /// Constructs an executor for a sequence of <seealso cref="LexerAction"/> actions. </summary>
+    /// <param name="lexerActions"> The lexer actions to execute. </param>
+    LexerActionExecutor(const std::vector<Ref<LexerAction>> &lexerActions);
+    virtual ~LexerActionExecutor();
+
+    /// <summary>
+    /// Creates a <seealso cref="LexerActionExecutor"/> which executes the actions for
+    /// the input {@code lexerActionExecutor} followed by a specified
+    /// {@code lexerAction}.
+    /// </summary>
+    /// <param name="lexerActionExecutor"> The executor for actions already traversed by
+    /// the lexer while matching a token within a particular
+    /// <seealso cref="LexerATNConfig"/>. If this is {@code null}, the method behaves as
+    /// though it were an empty executor. </param>
+    /// <param name="lexerAction"> The lexer action to execute after the actions
+    /// specified in {@code lexerActionExecutor}.
+    /// </param>
+    /// <returns> A <seealso cref="LexerActionExecutor"/> for executing the combine actions
+    /// of {@code lexerActionExecutor} and {@code lexerAction}. </returns>
+    static Ref<LexerActionExecutor> append(Ref<LexerActionExecutor> const& lexerActionExecutor,
+                                           Ref<LexerAction> const& lexerAction);
+
+    /// <summary>
+    /// Creates a <seealso cref="LexerActionExecutor"/> which encodes the current offset
+    /// for position-dependent lexer actions.
+    ///
+    /// <para>Normally, when the executor encounters lexer actions where
+    /// <seealso cref="LexerAction#isPositionDependent"/> returns {@code true}, it calls
+    /// <seealso cref="IntStream#seek"/> on the input <seealso cref="CharStream"/> to set the input
+    /// position to the <em>end</em> of the current token. This behavior provides
+    /// for efficient DFA representation of lexer actions which appear at the end
+    /// of a lexer rule, even when the lexer rule matches a variable number of
+    /// characters.</para>
+    ///
+    /// <para>Prior to traversing a match transition in the ATN, the current offset
+    /// from the token start index is assigned to all position-dependent lexer
+    /// actions which have not already been assigned a fixed offset. By storing
+    /// the offsets relative to the token start index, the DFA representation of
+    /// lexer actions which appear in the middle of tokens remains efficient due
+    /// to sharing among tokens of the same length, regardless of their absolute
+    /// position in the input stream.</para>
+    ///
+    /// <para>If the current executor already has offsets assigned to all
+    /// position-dependent lexer actions, the method returns {@code this}.</para>
+    /// </summary>
+    /// <param name="offset"> The current offset to assign to all position-dependent
+    /// lexer actions which do not already have offsets assigned.
+    /// </param>
+    /// <returns> A <seealso cref="LexerActionExecutor"/> which stores input stream offsets
+    /// for all position-dependent lexer actions. </returns>
+    virtual Ref<LexerActionExecutor> fixOffsetBeforeMatch(int offset);
+
+    /// <summary>
+    /// Gets the lexer actions to be executed by this executor. </summary>
+    /// <returns> The lexer actions to be executed by this executor. </returns>
+    virtual std::vector<Ref<LexerAction>> getLexerActions() const;
+
+    /// <summary>
+    /// Execute the actions encapsulated by this executor within the context of a
+    /// particular <seealso cref="Lexer"/>.
+    ///
+    /// <para>This method calls <seealso cref="IntStream#seek"/> to set the position of the
+    /// {@code input} <seealso cref="CharStream"/> prior to calling
+    /// <seealso cref="LexerAction#execute"/> on a position-dependent action. Before the
+    /// method returns, the input position will be restored to the same position
+    /// it was in when the method was invoked.</para>
+    /// </summary>
+    /// <param name="lexer"> The lexer instance. </param>
+    /// <param name="input"> The input stream which is the source for the current token.
+    /// When this method is called, the current <seealso cref="IntStream#index"/> for
+    /// {@code input} should be the start of the following token, i.e. 1
+    /// character past the end of the current token. </param>
+    /// <param name="startIndex"> The token start index. This value may be passed to
+    /// <seealso cref="IntStream#seek"/> to set the {@code input} position to the beginning
+    /// of the token. </param>
+    virtual void execute(Lexer *lexer, CharStream *input, size_t startIndex);
+
+    virtual size_t hashCode() const;
+    virtual bool operator == (const LexerActionExecutor &obj) const;
+    virtual bool operator != (const LexerActionExecutor &obj) const;
+
+  private:
+    const std::vector<Ref<LexerAction>> _lexerActions;
+
+    /// Caches the result of <seealso cref="#hashCode"/> since the hash code is an element
+    /// of the performance-critical <seealso cref="LexerATNConfig#hashCode"/> operation.
+    const size_t _hashCode;
+
+    size_t generateHashCode() const;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerActionType.h

@@ -0,0 +1,55 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "antlr4-common.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// Represents the serialization type of a <seealso cref="LexerAction"/>.
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  enum class LexerActionType : size_t {
+    /// <summary>
+    /// The type of a <seealso cref="LexerChannelAction"/> action.
+    /// </summary>
+    CHANNEL,
+    /// <summary>
+    /// The type of a <seealso cref="LexerCustomAction"/> action.
+    /// </summary>
+    CUSTOM,
+    /// <summary>
+    /// The type of a <seealso cref="LexerModeAction"/> action.
+    /// </summary>
+    MODE,
+    /// <summary>
+    /// The type of a <seealso cref="LexerMoreAction"/> action.
+    /// </summary>
+    MORE,
+    /// <summary>
+    /// The type of a <seealso cref="LexerPopModeAction"/> action.
+    /// </summary>
+    POP_MODE,
+    /// <summary>
+    /// The type of a <seealso cref="LexerPushModeAction"/> action.
+    /// </summary>
+    PUSH_MODE,
+    /// <summary>
+    /// The type of a <seealso cref="LexerSkipAction"/> action.
+    /// </summary>
+    SKIP,
+    /// <summary>
+    /// The type of a <seealso cref="LexerTypeAction"/> action.
+    /// </summary>
+    TYPE,
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerChannelAction.h

@@ -0,0 +1,63 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerAction.h"
+#include "atn/LexerActionType.h"
+
+namespace antlr4 {
+namespace atn {
+
+  using antlr4::Lexer;
+
+  /// <summary>
+  /// Implements the {@code channel} lexer action by calling
+  /// <seealso cref="Lexer#setChannel"/> with the assigned channel.
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  class ANTLR4CPP_PUBLIC LexerChannelAction final : public LexerAction {
+  public:
+    /// <summary>
+    /// Constructs a new {@code channel} action with the specified channel value. </summary>
+    /// <param name="channel"> The channel value to pass to <seealso cref="Lexer#setChannel"/>. </param>
+    LexerChannelAction(int channel);
+
+    /// <summary>
+    /// Gets the channel to use for the <seealso cref="Token"/> created by the lexer.
+    /// </summary>
+    /// <returns> The channel to use for the <seealso cref="Token"/> created by the lexer. </returns>
+    int getChannel() const;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns <seealso cref="LexerActionType#CHANNEL"/>. </returns>
+    virtual LexerActionType getActionType() const override;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns {@code false}. </returns>
+    virtual bool isPositionDependent() const override;
+
+    /// <summary>
+    /// {@inheritDoc}
+    ///
+    /// <para>This action is implemented by calling <seealso cref="Lexer#setChannel"/> with the
+    /// value provided by <seealso cref="#getChannel"/>.</para>
+    /// </summary>
+    virtual void execute(Lexer *lexer) override;
+
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const LexerAction &obj) const override;
+    virtual std::string toString() const override;
+
+  private:
+    const int _channel;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerCustomAction.h

@@ -0,0 +1,87 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerAction.h"
+#include "atn/LexerActionType.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// Executes a custom lexer action by calling <seealso cref="Recognizer#action"/> with the
+  /// rule and action indexes assigned to the custom action. The implementation of
+  /// a custom action is added to the generated code for the lexer in an override
+  /// of <seealso cref="Recognizer#action"/> when the grammar is compiled.
+  ///
+  /// <para>This class may represent embedded actions created with the <code>{...}</code>
+  /// syntax in ANTLR 4, as well as actions created for lexer commands where the
+  /// command argument could not be evaluated when the grammar was compiled.</para>
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  class ANTLR4CPP_PUBLIC LexerCustomAction final : public LexerAction {
+  public:
+    /// <summary>
+    /// Constructs a custom lexer action with the specified rule and action
+    /// indexes.
+    /// </summary>
+    /// <param name="ruleIndex"> The rule index to use for calls to
+    /// <seealso cref="Recognizer#action"/>. </param>
+    /// <param name="actionIndex"> The action index to use for calls to
+    /// <seealso cref="Recognizer#action"/>. </param>
+    LexerCustomAction(size_t ruleIndex, size_t actionIndex);
+
+    /// <summary>
+    /// Gets the rule index to use for calls to <seealso cref="Recognizer#action"/>.
+    /// </summary>
+    /// <returns> The rule index for the custom action. </returns>
+    size_t getRuleIndex() const;
+
+    /// <summary>
+    /// Gets the action index to use for calls to <seealso cref="Recognizer#action"/>.
+    /// </summary>
+    /// <returns> The action index for the custom action. </returns>
+    size_t getActionIndex() const;
+
+    /// <summary>
+    /// {@inheritDoc}
+    /// </summary>
+    /// <returns> This method returns <seealso cref="LexerActionType#CUSTOM"/>. </returns>
+    virtual LexerActionType getActionType() const override;
+
+    /// <summary>
+    /// Gets whether the lexer action is position-dependent. Position-dependent
+    /// actions may have different semantics depending on the <seealso cref="CharStream"/>
+    /// index at the time the action is executed.
+    ///
+    /// <para>Custom actions are position-dependent since they may represent a
+    /// user-defined embedded action which makes calls to methods like
+    /// <seealso cref="Lexer#getText"/>.</para>
+    /// </summary>
+    /// <returns> This method returns {@code true}. </returns>
+    virtual bool isPositionDependent() const override;
+
+    /// <summary>
+    /// {@inheritDoc}
+    ///
+    /// <para>Custom actions are implemented by calling <seealso cref="Lexer#action"/> with the
+    /// appropriate rule and action indexes.</para>
+    /// </summary>
+    virtual void execute(Lexer *lexer) override;
+
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const LexerAction &obj) const override;
+    virtual std::string toString() const override;
+
+  private:
+    const size_t _ruleIndex;
+    const size_t _actionIndex;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerIndexedCustomAction.h

@@ -0,0 +1,82 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "RuleContext.h"
+#include "atn/LexerAction.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// This implementation of <seealso cref="LexerAction"/> is used for tracking input offsets
+  /// for position-dependent actions within a <seealso cref="LexerActionExecutor"/>.
+  ///
+  /// <para>This action is not serialized as part of the ATN, and is only required for
+  /// position-dependent lexer actions which appear at a location other than the
+  /// end of a rule. For more information about DFA optimizations employed for
+  /// lexer actions, see <seealso cref="LexerActionExecutor#append"/> and
+  /// <seealso cref="LexerActionExecutor#fixOffsetBeforeMatch"/>.</para>
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  class ANTLR4CPP_PUBLIC LexerIndexedCustomAction final : public LexerAction {
+  public:
+    /// <summary>
+    /// Constructs a new indexed custom action by associating a character offset
+    /// with a <seealso cref="LexerAction"/>.
+    ///
+    /// <para>Note: This class is only required for lexer actions for which
+    /// <seealso cref="LexerAction#isPositionDependent"/> returns {@code true}.</para>
+    /// </summary>
+    /// <param name="offset"> The offset into the input <seealso cref="CharStream"/>, relative to
+    /// the token start index, at which the specified lexer action should be
+    /// executed. </param>
+    /// <param name="action"> The lexer action to execute at a particular offset in the
+    /// input <seealso cref="CharStream"/>. </param>
+    LexerIndexedCustomAction(int offset, Ref<LexerAction> const& action);
+
+    /// <summary>
+    /// Gets the location in the input <seealso cref="CharStream"/> at which the lexer
+    /// action should be executed. The value is interpreted as an offset relative
+    /// to the token start index.
+    /// </summary>
+    /// <returns> The location in the input <seealso cref="CharStream"/> at which the lexer
+    /// action should be executed. </returns>
+    int getOffset() const;
+
+    /// <summary>
+    /// Gets the lexer action to execute.
+    /// </summary>
+    /// <returns> A <seealso cref="LexerAction"/> object which executes the lexer action. </returns>
+    Ref<LexerAction> getAction() const;
+
+    /// <summary>
+    /// {@inheritDoc}
+    /// </summary>
+    /// <returns> This method returns the result of calling <seealso cref="#getActionType"/>
+    /// on the <seealso cref="LexerAction"/> returned by <seealso cref="#getAction"/>. </returns>
+    virtual LexerActionType getActionType() const override;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns {@code true}. </returns>
+    virtual bool isPositionDependent() const override;
+
+    virtual void execute(Lexer *lexer) override;
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const LexerAction &obj) const override;
+    virtual std::string toString() const override;
+
+  private:
+    const int _offset;
+    const Ref<LexerAction> _action;
+  };
+
+} // namespace atn
+} // namespace antlr4
+

lib/antlr4/include/atn/LexerModeAction.h

@@ -0,0 +1,61 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerAction.h"
+#include "atn/LexerActionType.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// Implements the {@code mode} lexer action by calling <seealso cref="Lexer#mode"/> with
+  /// the assigned mode.
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  class ANTLR4CPP_PUBLIC LexerModeAction final : public LexerAction {
+  public:
+    /// <summary>
+    /// Constructs a new {@code mode} action with the specified mode value. </summary>
+    /// <param name="mode"> The mode value to pass to <seealso cref="Lexer#mode"/>. </param>
+    LexerModeAction(int mode);
+
+    /// <summary>
+    /// Get the lexer mode this action should transition the lexer to.
+    /// </summary>
+    /// <returns> The lexer mode for this {@code mode} command. </returns>
+    int getMode();
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns <seealso cref="LexerActionType#MODE"/>. </returns>
+    virtual LexerActionType getActionType() const override;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns {@code false}. </returns>
+    virtual bool isPositionDependent() const override;
+
+    /// <summary>
+    /// {@inheritDoc}
+    ///
+    /// <para>This action is implemented by calling <seealso cref="Lexer#mode"/> with the
+    /// value provided by <seealso cref="#getMode"/>.</para>
+    /// </summary>
+    virtual void execute(Lexer *lexer) override;
+
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const LexerAction &obj) const override;
+    virtual std::string toString() const override;
+
+  private:
+    const int _mode;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerMoreAction.h

@@ -0,0 +1,57 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerAction.h"
+#include "atn/LexerActionType.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// Implements the {@code more} lexer action by calling <seealso cref="Lexer#more"/>.
+  ///
+  /// <para>The {@code more} command does not have any parameters, so this action is
+  /// implemented as a singleton instance exposed by <seealso cref="#INSTANCE"/>.</para>
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  class ANTLR4CPP_PUBLIC LexerMoreAction final : public LexerAction {
+  public:
+    /// <summary>
+    /// Provides a singleton instance of this parameterless lexer action.
+    /// </summary>
+    static const Ref<LexerMoreAction> getInstance();
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns <seealso cref="LexerActionType#MORE"/>. </returns>
+    virtual LexerActionType getActionType() const override;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns {@code false}. </returns>
+    virtual bool isPositionDependent() const override;
+
+    /// <summary>
+    /// {@inheritDoc}
+    ///
+    /// <para>This action is implemented by calling <seealso cref="Lexer#more"/>.</para>
+    /// </summary>
+    virtual void execute(Lexer *lexer) override;
+
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const LexerAction &obj) const override;
+    virtual std::string toString() const override;
+
+  private:
+    /// Constructs the singleton instance of the lexer {@code more} command.
+    LexerMoreAction();
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerPopModeAction.h

@@ -0,0 +1,57 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerAction.h"
+#include "atn/LexerActionType.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// Implements the {@code popMode} lexer action by calling <seealso cref="Lexer#popMode"/>.
+  ///
+  /// <para>The {@code popMode} command does not have any parameters, so this action is
+  /// implemented as a singleton instance exposed by <seealso cref="#INSTANCE"/>.</para>
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  class ANTLR4CPP_PUBLIC LexerPopModeAction final : public LexerAction {
+  public:
+    /// <summary>
+    /// Provides a singleton instance of this parameterless lexer action.
+    /// </summary>
+    static const Ref<LexerPopModeAction> getInstance();
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns <seealso cref="LexerActionType#POP_MODE"/>. </returns>
+    virtual LexerActionType getActionType() const override;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns {@code false}. </returns>
+    virtual bool isPositionDependent() const override;
+
+    /// <summary>
+    /// {@inheritDoc}
+    ///
+    /// <para>This action is implemented by calling <seealso cref="Lexer#popMode"/>.</para>
+    /// </summary>
+    virtual void execute(Lexer *lexer) override;
+
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const LexerAction &obj) const override;
+    virtual std::string toString() const override;
+
+  private:
+    /// Constructs the singleton instance of the lexer {@code popMode} command.
+    LexerPopModeAction();
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerPushModeAction.h

@@ -0,0 +1,61 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerAction.h"
+#include "atn/LexerActionType.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// Implements the {@code pushMode} lexer action by calling
+  /// <seealso cref="Lexer#pushMode"/> with the assigned mode.
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  class ANTLR4CPP_PUBLIC LexerPushModeAction final : public LexerAction {
+  public:
+    /// <summary>
+    /// Constructs a new {@code pushMode} action with the specified mode value. </summary>
+    /// <param name="mode"> The mode value to pass to <seealso cref="Lexer#pushMode"/>. </param>
+    LexerPushModeAction(int mode);
+
+    /// <summary>
+    /// Get the lexer mode this action should transition the lexer to.
+    /// </summary>
+    /// <returns> The lexer mode for this {@code pushMode} command. </returns>
+    int getMode() const;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns <seealso cref="LexerActionType#PUSH_MODE"/>. </returns>
+    virtual LexerActionType getActionType() const override;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns {@code false}. </returns>
+    virtual bool isPositionDependent() const override;
+
+    /// <summary>
+    /// {@inheritDoc}
+    ///
+    /// <para>This action is implemented by calling <seealso cref="Lexer#pushMode"/> with the
+    /// value provided by <seealso cref="#getMode"/>.</para>
+    /// </summary>
+    virtual void execute(Lexer *lexer) override;
+
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const LexerAction &obj) const override;
+    virtual std::string toString() const override;
+
+  private:
+    const int _mode;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerSkipAction.h

@@ -0,0 +1,55 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerAction.h"
+#include "atn/LexerActionType.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// Implements the {@code skip} lexer action by calling <seealso cref="Lexer#skip"/>.
+  ///
+  /// <para>The {@code skip} command does not have any parameters, so this action is
+  /// implemented as a singleton instance exposed by <seealso cref="#INSTANCE"/>.</para>
+  ///
+  /// @author Sam Harwell
+  /// @since 4.2
+  /// </summary>
+  class ANTLR4CPP_PUBLIC LexerSkipAction final : public LexerAction {
+  public:
+    /// Provides a singleton instance of this parameterless lexer action.
+    static const Ref<LexerSkipAction> getInstance();
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns <seealso cref="LexerActionType#SKIP"/>. </returns>
+    virtual LexerActionType getActionType() const override;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns {@code false}. </returns>
+    virtual bool isPositionDependent() const override;
+
+    /// <summary>
+    /// {@inheritDoc}
+    ///
+    /// <para>This action is implemented by calling <seealso cref="Lexer#skip"/>.</para>
+    /// </summary>
+    virtual void execute(Lexer *lexer) override;
+
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const LexerAction &obj) const override;
+    virtual std::string toString() const override;
+
+  private:
+    /// Constructs the singleton instance of the lexer {@code skip} command.
+    LexerSkipAction();
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LexerTypeAction.h

@@ -0,0 +1,55 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/LexerActionType.h"
+#include "atn/LexerAction.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// Implements the {@code type} lexer action by calling <seealso cref="Lexer#setType"/>
+  /// with the assigned type.
+  class ANTLR4CPP_PUBLIC LexerTypeAction : public LexerAction {
+  public:
+    /// <summary>
+    /// Constructs a new {@code type} action with the specified token type value. </summary>
+    /// <param name="type"> The type to assign to the token using <seealso cref="Lexer#setType"/>. </param>
+    LexerTypeAction(int type);
+
+    /// <summary>
+    /// Gets the type to assign to a token created by the lexer. </summary>
+    /// <returns> The type to assign to a token created by the lexer. </returns>
+    virtual int getType() const;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns <seealso cref="LexerActionType#TYPE"/>. </returns>
+    virtual LexerActionType getActionType() const override;
+
+    /// <summary>
+    /// {@inheritDoc} </summary>
+    /// <returns> This method returns {@code false}. </returns>
+    virtual bool isPositionDependent() const override;
+
+    /// <summary>
+    /// {@inheritDoc}
+    ///
+    /// <para>This action is implemented by calling <seealso cref="Lexer#setType"/> with the
+    /// value provided by <seealso cref="#getType"/>.</para>
+    /// </summary>
+    virtual void execute(Lexer *lexer) override;
+
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const LexerAction &obj) const override;
+    virtual std::string toString() const override;
+
+  private:
+    const int _type;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LookaheadEventInfo.h

@@ -0,0 +1,42 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionEventInfo.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// This class represents profiling event information for tracking the lookahead
+  /// depth required in order to make a prediction.
+  class ANTLR4CPP_PUBLIC LookaheadEventInfo : public DecisionEventInfo {
+  public:
+    /// The alternative chosen by adaptivePredict(), not necessarily
+    ///  the outermost alt shown for a rule; left-recursive rules have
+    ///  user-level alts that differ from the rewritten rule with a (...) block
+    ///  and a (..)* loop.
+    size_t predictedAlt = 0;
+
+    /// <summary>
+    /// Constructs a new instance of the <seealso cref="LookaheadEventInfo"/> class with
+    /// the specified detailed lookahead information.
+    /// </summary>
+    /// <param name="decision"> The decision number </param>
+    /// <param name="configs"> The final configuration set containing the necessary
+    /// information to determine the result of a prediction, or {@code null} if
+    /// the final configuration set is not available </param>
+    /// <param name="input"> The input token stream </param>
+    /// <param name="startIndex"> The start index for the current prediction </param>
+    /// <param name="stopIndex"> The index at which the prediction was finally made </param>
+    /// <param name="fullCtx"> {@code true} if the current lookahead is part of an LL
+    /// prediction; otherwise, {@code false} if the current lookahead is part of
+    /// an SLL prediction </param>
+    LookaheadEventInfo(size_t decision, ATNConfigSet *configs, size_t predictedAlt, TokenStream *input, size_t startIndex,
+                       size_t stopIndex, bool fullCtx);
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/LoopEndState.h

@@ -0,0 +1,22 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// Mark the end of a * or + loop.
+  class ANTLR4CPP_PUBLIC LoopEndState final : public ATNState {
+  public:
+    ATNState *loopBackState = nullptr;
+
+    virtual size_t getStateType() override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/NotSetTransition.h

@@ -0,0 +1,25 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/SetTransition.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC NotSetTransition final : public SetTransition {
+  public:
+    NotSetTransition(ATNState *target, const misc::IntervalSet &set);
+
+    virtual SerializationType getSerializationType() const override;
+
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/OrderedATNConfigSet.h

@@ -0,0 +1,20 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNConfigSet.h"
+#include "atn/ATNConfig.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC OrderedATNConfigSet : public ATNConfigSet {
+  protected:
+    virtual size_t getHash(ATNConfig *c) override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ParseInfo.h

@@ -0,0 +1,102 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionInfo.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ProfilingATNSimulator;
+
+  /// This class provides access to specific and aggregate statistics gathered
+  /// during profiling of a parser.
+  class ANTLR4CPP_PUBLIC ParseInfo {
+  public:
+    ParseInfo(ProfilingATNSimulator *atnSimulator);
+    ParseInfo(ParseInfo const&) = default;
+    virtual ~ParseInfo();
+
+    ParseInfo& operator=(ParseInfo const&) = default;
+
+    /// <summary>
+    /// Gets an array of <seealso cref="DecisionInfo"/> instances containing the profiling
+    /// information gathered for each decision in the ATN.
+    /// </summary>
+    /// <returns> An array of <seealso cref="DecisionInfo"/> instances, indexed by decision
+    /// number. </returns>
+    virtual std::vector<DecisionInfo> getDecisionInfo();
+
+    /// <summary>
+    /// Gets the decision numbers for decisions that required one or more
+    /// full-context predictions during parsing. These are decisions for which
+    /// <seealso cref="DecisionInfo#LL_Fallback"/> is non-zero.
+    /// </summary>
+    /// <returns> A list of decision numbers which required one or more
+    /// full-context predictions during parsing. </returns>
+    virtual std::vector<size_t> getLLDecisions();
+
+    /// <summary>
+    /// Gets the total time spent during prediction across all decisions made
+    /// during parsing. This value is the sum of
+    /// <seealso cref="DecisionInfo#timeInPrediction"/> for all decisions.
+    /// </summary>
+    virtual long long getTotalTimeInPrediction();
+
+    /// <summary>
+    /// Gets the total number of SLL lookahead operations across all decisions
+    /// made during parsing. This value is the sum of
+    /// <seealso cref="DecisionInfo#SLL_TotalLook"/> for all decisions.
+    /// </summary>
+    virtual long long getTotalSLLLookaheadOps();
+
+    /// <summary>
+    /// Gets the total number of LL lookahead operations across all decisions
+    /// made during parsing. This value is the sum of
+    /// <seealso cref="DecisionInfo#LL_TotalLook"/> for all decisions.
+    /// </summary>
+    virtual long long getTotalLLLookaheadOps();
+
+    /// <summary>
+    /// Gets the total number of ATN lookahead operations for SLL prediction
+    /// across all decisions made during parsing.
+    /// </summary>
+    virtual long long getTotalSLLATNLookaheadOps();
+
+    /// <summary>
+    /// Gets the total number of ATN lookahead operations for LL prediction
+    /// across all decisions made during parsing.
+    /// </summary>
+    virtual long long getTotalLLATNLookaheadOps();
+
+    /// <summary>
+    /// Gets the total number of ATN lookahead operations for SLL and LL
+    /// prediction across all decisions made during parsing.
+    ///
+    /// <para>
+    /// This value is the sum of <seealso cref="#getTotalSLLATNLookaheadOps"/> and
+    /// <seealso cref="#getTotalLLATNLookaheadOps"/>.</para>
+    /// </summary>
+    virtual long long getTotalATNLookaheadOps();
+
+    /// <summary>
+    /// Gets the total number of DFA states stored in the DFA cache for all
+    /// decisions in the ATN.
+    /// </summary>
+    virtual size_t getDFASize();
+
+    /// <summary>
+    /// Gets the total number of DFA states stored in the DFA cache for a
+    /// particular decision.
+    /// </summary>
+    virtual size_t getDFASize(size_t decision);
+
+  protected:
+    const ProfilingATNSimulator *_atnSimulator; // non-owning, we are created by this simulator.
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ParserATNSimulator.h

@@ -0,0 +1,904 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "PredictionMode.h"
+#include "dfa/DFAState.h"
+#include "atn/ATNSimulator.h"
+#include "atn/PredictionContext.h"
+#include "SemanticContext.h"
+#include "atn/ATNConfig.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /**
+   * The embodiment of the adaptive LL(*), ALL(*), parsing strategy.
+   *
+   * <p>
+   * The basic complexity of the adaptive strategy makes it harder to understand.
+   * We begin with ATN simulation to build paths in a DFA. Subsequent prediction
+   * requests go through the DFA first. If they reach a state without an edge for
+   * the current symbol, the algorithm fails over to the ATN simulation to
+   * complete the DFA path for the current input (until it finds a conflict state
+   * or uniquely predicting state).</p>
+   *
+   * <p>
+   * All of that is done without using the outer context because we want to create
+   * a DFA that is not dependent upon the rule invocation stack when we do a
+   * prediction. One DFA works in all contexts. We avoid using context not
+   * necessarily because it's slower, although it can be, but because of the DFA
+   * caching problem. The closure routine only considers the rule invocation stack
+   * created during prediction beginning in the decision rule. For example, if
+   * prediction occurs without invoking another rule's ATN, there are no context
+   * stacks in the configurations. When lack of context leads to a conflict, we
+   * don't know if it's an ambiguity or a weakness in the strong LL(*) parsing
+   * strategy (versus full LL(*)).</p>
+   *
+   * <p>
+   * When SLL yields a configuration set with conflict, we rewind the input and
+   * retry the ATN simulation, this time using full outer context without adding
+   * to the DFA. Configuration context stacks will be the full invocation stacks
+   * from the start rule. If we get a conflict using full context, then we can
+   * definitively say we have a true ambiguity for that input sequence. If we
+   * don't get a conflict, it implies that the decision is sensitive to the outer
+   * context. (It is not context-sensitive in the sense of context-sensitive
+   * grammars.)</p>
+   *
+   * <p>
+   * The next time we reach this DFA state with an SLL conflict, through DFA
+   * simulation, we will again retry the ATN simulation using full context mode.
+   * This is slow because we can't save the results and have to "interpret" the
+   * ATN each time we get that input.</p>
+   *
+   * <p>
+   * <strong>CACHING FULL CONTEXT PREDICTIONS</strong></p>
+   *
+   * <p>
+   * We could cache results from full context to predicted alternative easily and
+   * that saves a lot of time but doesn't work in presence of predicates. The set
+   * of visible predicates from the ATN start state changes depending on the
+   * context, because closure can fall off the end of a rule. I tried to cache
+   * tuples (stack context, semantic context, predicted alt) but it was slower
+   * than interpreting and much more complicated. Also required a huge amount of
+   * memory. The goal is not to create the world's fastest parser anyway. I'd like
+   * to keep this algorithm simple. By launching multiple threads, we can improve
+   * the speed of parsing across a large number of files.</p>
+   *
+   * <p>
+   * There is no strict ordering between the amount of input used by SLL vs LL,
+   * which makes it really hard to build a cache for full context. Let's say that
+   * we have input A B C that leads to an SLL conflict with full context X. That
+   * implies that using X we might only use A B but we could also use A B C D to
+   * resolve conflict. Input A B C D could predict alternative 1 in one position
+   * in the input and A B C E could predict alternative 2 in another position in
+   * input. The conflicting SLL configurations could still be non-unique in the
+   * full context prediction, which would lead us to requiring more input than the
+   * original A B C.	To make a	prediction cache work, we have to track	the exact
+   * input	used during the previous prediction. That amounts to a cache that maps
+   * X to a specific DFA for that context.</p>
+   *
+   * <p>
+   * Something should be done for left-recursive expression predictions. They are
+   * likely LL(1) + pred eval. Easier to do the whole SLL unless error and retry
+   * with full LL thing Sam does.</p>
+   *
+   * <p>
+   * <strong>AVOIDING FULL CONTEXT PREDICTION</strong></p>
+   *
+   * <p>
+   * We avoid doing full context retry when the outer context is empty, we did not
+   * dip into the outer context by falling off the end of the decision state rule,
+   * or when we force SLL mode.</p>
+   *
+   * <p>
+   * As an example of the not dip into outer context case, consider as super
+   * constructor calls versus function calls. One grammar might look like
+   * this:</p>
+   *
+   * <pre>
+   * ctorBody
+   *   : '{' superCall? stat* '}'
+   *   ;
+   * </pre>
+   *
+   * <p>
+   * Or, you might see something like</p>
+   *
+   * <pre>
+   * stat
+   *   : superCall ';'
+   *   | expression ';'
+   *   | ...
+   *   ;
+   * </pre>
+   *
+   * <p>
+   * In both cases I believe that no closure operations will dip into the outer
+   * context. In the first case ctorBody in the worst case will stop at the '}'.
+   * In the 2nd case it should stop at the ';'. Both cases should stay within the
+   * entry rule and not dip into the outer context.</p>
+   *
+   * <p>
+   * <strong>PREDICATES</strong></p>
+   *
+   * <p>
+   * Predicates are always evaluated if present in either SLL or LL both. SLL and
+   * LL simulation deals with predicates differently. SLL collects predicates as
+   * it performs closure operations like ANTLR v3 did. It delays predicate
+   * evaluation until it reaches and accept state. This allows us to cache the SLL
+   * ATN simulation whereas, if we had evaluated predicates on-the-fly during
+   * closure, the DFA state configuration sets would be different and we couldn't
+   * build up a suitable DFA.</p>
+   *
+   * <p>
+   * When building a DFA accept state during ATN simulation, we evaluate any
+   * predicates and return the sole semantically valid alternative. If there is
+   * more than 1 alternative, we report an ambiguity. If there are 0 alternatives,
+   * we throw an exception. Alternatives without predicates act like they have
+   * true predicates. The simple way to think about it is to strip away all
+   * alternatives with false predicates and choose the minimum alternative that
+   * remains.</p>
+   *
+   * <p>
+   * When we start in the DFA and reach an accept state that's predicated, we test
+   * those and return the minimum semantically viable alternative. If no
+   * alternatives are viable, we throw an exception.</p>
+   *
+   * <p>
+   * During full LL ATN simulation, closure always evaluates predicates and
+   * on-the-fly. This is crucial to reducing the configuration set size during
+   * closure. It hits a landmine when parsing with the Java grammar, for example,
+   * without this on-the-fly evaluation.</p>
+   *
+   * <p>
+   * <strong>SHARING DFA</strong></p>
+   *
+   * <p>
+   * All instances of the same parser share the same decision DFAs through a
+   * static field. Each instance gets its own ATN simulator but they share the
+   * same {@link #decisionToDFA} field. They also share a
+   * {@link PredictionContextCache} object that makes sure that all
+   * {@link PredictionContext} objects are shared among the DFA states. This makes
+   * a big size difference.</p>
+   *
+   * <p>
+   * <strong>THREAD SAFETY</strong></p>
+   *
+   * <p>
+   * The {@link ParserATNSimulator} locks on the {@link #decisionToDFA} field when
+   * it adds a new DFA object to that array. {@link #addDFAEdge}
+   * locks on the DFA for the current decision when setting the
+   * {@link DFAState#edges} field. {@link #addDFAState} locks on
+   * the DFA for the current decision when looking up a DFA state to see if it
+   * already exists. We must make sure that all requests to add DFA states that
+   * are equivalent result in the same shared DFA object. This is because lots of
+   * threads will be trying to update the DFA at once. The
+   * {@link #addDFAState} method also locks inside the DFA lock
+   * but this time on the shared context cache when it rebuilds the
+   * configurations' {@link PredictionContext} objects using cached
+   * subgraphs/nodes. No other locking occurs, even during DFA simulation. This is
+   * safe as long as we can guarantee that all threads referencing
+   * {@code s.edge[t]} get the same physical target {@link DFAState}, or
+   * {@code null}. Once into the DFA, the DFA simulation does not reference the
+   * {@link DFA#states} map. It follows the {@link DFAState#edges} field to new
+   * targets. The DFA simulator will either find {@link DFAState#edges} to be
+   * {@code null}, to be non-{@code null} and {@code dfa.edges[t]} null, or
+   * {@code dfa.edges[t]} to be non-null. The
+   * {@link #addDFAEdge} method could be racing to set the field
+   * but in either case the DFA simulator works; if {@code null}, and requests ATN
+   * simulation. It could also race trying to get {@code dfa.edges[t]}, but either
+   * way it will work because it's not doing a test and set operation.</p>
+   *
+   * <p>
+   * <strong>Starting with SLL then failing to combined SLL/LL (Two-Stage
+   * Parsing)</strong></p>
+   *
+   * <p>
+   * Sam pointed out that if SLL does not give a syntax error, then there is no
+   * point in doing full LL, which is slower. We only have to try LL if we get a
+   * syntax error. For maximum speed, Sam starts the parser set to pure SLL
+   * mode with the {@link BailErrorStrategy}:</p>
+   *
+   * <pre>
+   * parser.{@link Parser#getInterpreter() getInterpreter()}.{@link #setPredictionMode setPredictionMode}{@code (}{@link PredictionMode#SLL}{@code )};
+   * parser.{@link Parser#setErrorHandler setErrorHandler}(new {@link BailErrorStrategy}());
+   * </pre>
+   *
+   * <p>
+   * If it does not get a syntax error, then we're done. If it does get a syntax
+   * error, we need to retry with the combined SLL/LL strategy.</p>
+   *
+   * <p>
+   * The reason this works is as follows. If there are no SLL conflicts, then the
+   * grammar is SLL (at least for that input set). If there is an SLL conflict,
+   * the full LL analysis must yield a set of viable alternatives which is a
+   * subset of the alternatives reported by SLL. If the LL set is a singleton,
+   * then the grammar is LL but not SLL. If the LL set is the same size as the SLL
+   * set, the decision is SLL. If the LL set has size &gt; 1, then that decision
+   * is truly ambiguous on the current input. If the LL set is smaller, then the
+   * SLL conflict resolution might choose an alternative that the full LL would
+   * rule out as a possibility based upon better context information. If that's
+   * the case, then the SLL parse will definitely get an error because the full LL
+   * analysis says it's not viable. If SLL conflict resolution chooses an
+   * alternative within the LL set, them both SLL and LL would choose the same
+   * alternative because they both choose the minimum of multiple conflicting
+   * alternatives.</p>
+   *
+   * <p>
+   * Let's say we have a set of SLL conflicting alternatives {@code {1, 2, 3}} and
+   * a smaller LL set called <em>s</em>. If <em>s</em> is {@code {2, 3}}, then SLL
+   * parsing will get an error because SLL will pursue alternative 1. If
+   * <em>s</em> is {@code {1, 2}} or {@code {1, 3}} then both SLL and LL will
+   * choose the same alternative because alternative one is the minimum of either
+   * set. If <em>s</em> is {@code {2}} or {@code {3}} then SLL will get a syntax
+   * error. If <em>s</em> is {@code {1}} then SLL will succeed.</p>
+   *
+   * <p>
+   * Of course, if the input is invalid, then we will get an error for sure in
+   * both SLL and LL parsing. Erroneous input will therefore require 2 passes over
+   * the input.</p>
+   */
+  class ANTLR4CPP_PUBLIC ParserATNSimulator : public ATNSimulator {
+  public:
+    /// Testing only!
+    ParserATNSimulator(const ATN &atn, std::vector<dfa::DFA> &decisionToDFA,
+                       PredictionContextCache &sharedContextCache);
+
+    ParserATNSimulator(Parser *parser, const ATN &atn, std::vector<dfa::DFA> &decisionToDFA,
+                       PredictionContextCache &sharedContextCache);
+
+    virtual void reset() override;
+    virtual void clearDFA() override;
+    virtual size_t adaptivePredict(TokenStream *input, size_t decision, ParserRuleContext *outerContext);
+    
+    static const bool TURN_OFF_LR_LOOP_ENTRY_BRANCH_OPT;
+
+    std::vector<dfa::DFA> &decisionToDFA;
+    
+    /** Implements first-edge (loop entry) elimination as an optimization
+     *  during closure operations.  See antlr/antlr4#1398.
+     *
+     * The optimization is to avoid adding the loop entry config when
+     * the exit path can only lead back to the same
+     * StarLoopEntryState after popping context at the rule end state
+     * (traversing only epsilon edges, so we're still in closure, in
+     * this same rule).
+     *
+     * We need to detect any state that can reach loop entry on
+     * epsilon w/o exiting rule. We don't have to look at FOLLOW
+     * links, just ensure that all stack tops for config refer to key
+     * states in LR rule.
+     *
+     * To verify we are in the right situation we must first check
+     * closure is at a StarLoopEntryState generated during LR removal.
+     * Then we check that each stack top of context is a return state
+     * from one of these cases:
+     *
+     *   1. 'not' expr, '(' type ')' expr. The return state points at loop entry state
+     *   2. expr op expr. The return state is the block end of internal block of (...)*
+     *   3. 'between' expr 'and' expr. The return state of 2nd expr reference.
+     *      That state points at block end of internal block of (...)*.
+     *   4. expr '?' expr ':' expr. The return state points at block end,
+     *      which points at loop entry state.
+     *
+     * If any is true for each stack top, then closure does not add a
+     * config to the current config set for edge[0], the loop entry branch.
+     *
+     *  Conditions fail if any context for the current config is:
+     *
+     *   a. empty (we'd fall out of expr to do a global FOLLOW which could
+     *      even be to some weird spot in expr) or,
+     *   b. lies outside of expr or,
+     *   c. lies within expr but at a state not the BlockEndState
+     *   generated during LR removal
+     *
+     * Do we need to evaluate predicates ever in closure for this case?
+     *
+     * No. Predicates, including precedence predicates, are only
+     * evaluated when computing a DFA start state. I.e., only before
+     * the lookahead (but not parser) consumes a token.
+     *
+     * There are no epsilon edges allowed in LR rule alt blocks or in
+     * the "primary" part (ID here). If closure is in
+     * StarLoopEntryState any lookahead operation will have consumed a
+     * token as there are no epsilon-paths that lead to
+     * StarLoopEntryState. We do not have to evaluate predicates
+     * therefore if we are in the generated StarLoopEntryState of a LR
+     * rule. Note that when making a prediction starting at that
+     * decision point, decision d=2, compute-start-state performs
+     * closure starting at edges[0], edges[1] emanating from
+     * StarLoopEntryState. That means it is not performing closure on
+     * StarLoopEntryState during compute-start-state.
+     *
+     * How do we know this always gives same prediction answer?
+     *
+     * Without predicates, loop entry and exit paths are ambiguous
+     * upon remaining input +b (in, say, a+b). Either paths lead to
+     * valid parses. Closure can lead to consuming + immediately or by
+     * falling out of this call to expr back into expr and loop back
+     * again to StarLoopEntryState to match +b. In this special case,
+     * we choose the more efficient path, which is to take the bypass
+     * path.
+     *
+     * The lookahead language has not changed because closure chooses
+     * one path over the other. Both paths lead to consuming the same
+     * remaining input during a lookahead operation. If the next token
+     * is an operator, lookahead will enter the choice block with
+     * operators. If it is not, lookahead will exit expr. Same as if
+     * closure had chosen to enter the choice block immediately.
+     *
+     * Closure is examining one config (some loopentrystate, some alt,
+     * context) which means it is considering exactly one alt. Closure
+     * always copies the same alt to any derived configs.
+     *
+     * How do we know this optimization doesn't mess up precedence in
+     * our parse trees?
+     *
+     * Looking through expr from left edge of stat only has to confirm
+     * that an input, say, a+b+c; begins with any valid interpretation
+     * of an expression. The precedence actually doesn't matter when
+     * making a decision in stat seeing through expr. It is only when
+     * parsing rule expr that we must use the precedence to get the
+     * right interpretation and, hence, parse tree.
+     */
+    bool canDropLoopEntryEdgeInLeftRecursiveRule(ATNConfig *config) const;
+    virtual std::string getRuleName(size_t index);
+
+    virtual Ref<ATNConfig> precedenceTransition(Ref<ATNConfig> const& config, PrecedencePredicateTransition *pt,
+                                                bool collectPredicates, bool inContext, bool fullCtx);
+
+    void setPredictionMode(PredictionMode newMode);
+    PredictionMode getPredictionMode();
+
+    Parser* getParser();
+    
+    virtual std::string getTokenName(size_t t);
+
+    virtual std::string getLookaheadName(TokenStream *input);
+
+    /// <summary>
+    /// Used for debugging in adaptivePredict around execATN but I cut
+    ///  it out for clarity now that alg. works well. We can leave this
+    ///  "dead" code for a bit.
+    /// </summary>
+    virtual void dumpDeadEndConfigs(NoViableAltException &nvae);
+    
+  protected:
+    Parser *const parser;
+
+    /// <summary>
+    /// Each prediction operation uses a cache for merge of prediction contexts.
+    /// Don't keep around as it wastes huge amounts of memory. The merge cache
+    /// isn't synchronized but we're ok since two threads shouldn't reuse same
+    /// parser/atnsim object because it can only handle one input at a time.
+    /// This maps graphs a and b to merged result c. (a,b)->c. We can avoid
+    /// the merge if we ever see a and b again.  Note that (b,a)->c should
+    /// also be examined during cache lookup.
+    /// </summary>
+    PredictionContextMergeCache mergeCache;
+
+    // LAME globals to avoid parameters!!!!! I need these down deep in predTransition
+    TokenStream *_input;
+    size_t _startIndex;
+    ParserRuleContext *_outerContext;
+    dfa::DFA *_dfa; // Reference into the decisionToDFA vector.
+    
+    /// <summary>
+    /// Performs ATN simulation to compute a predicted alternative based
+    ///  upon the remaining input, but also updates the DFA cache to avoid
+    ///  having to traverse the ATN again for the same input sequence.
+    ///
+    /// There are some key conditions we're looking for after computing a new
+    /// set of ATN configs (proposed DFA state):
+    /// if the set is empty, there is no viable alternative for current symbol
+    /// does the state uniquely predict an alternative?
+    /// does the state have a conflict that would prevent us from
+    ///         putting it on the work list?
+    ///
+    /// We also have some key operations to do:
+    /// add an edge from previous DFA state to potentially new DFA state, D,
+    ///         upon current symbol but only if adding to work list, which means in all
+    ///         cases except no viable alternative (and possibly non-greedy decisions?)
+    /// collecting predicates and adding semantic context to DFA accept states
+    /// adding rule context to context-sensitive DFA accept states
+    /// consuming an input symbol
+    /// reporting a conflict
+    /// reporting an ambiguity
+    /// reporting a context sensitivity
+    /// reporting insufficient predicates
+    ///
+    /// cover these cases:
+    ///    dead end
+    ///    single alt
+    ///    single alt + preds
+    ///    conflict
+    ///    conflict + preds
+    /// </summary>
+    virtual size_t execATN(dfa::DFA &dfa, dfa::DFAState *s0, TokenStream *input, size_t startIndex,
+                           ParserRuleContext *outerContext);
+
+    /// <summary>
+    /// Get an existing target state for an edge in the DFA. If the target state
+    /// for the edge has not yet been computed or is otherwise not available,
+    /// this method returns {@code null}.
+    /// </summary>
+    /// <param name="previousD"> The current DFA state </param>
+    /// <param name="t"> The next input symbol </param>
+    /// <returns> The existing target DFA state for the given input symbol
+    /// {@code t}, or {@code null} if the target state for this edge is not
+    /// already cached </returns>
+    virtual dfa::DFAState* getExistingTargetState(dfa::DFAState *previousD, size_t t);
+
+    /// <summary>
+    /// Compute a target state for an edge in the DFA, and attempt to add the
+    /// computed state and corresponding edge to the DFA.
+    /// </summary>
+    /// <param name="dfa"> The DFA </param>
+    /// <param name="previousD"> The current DFA state </param>
+    /// <param name="t"> The next input symbol
+    /// </param>
+    /// <returns> The computed target DFA state for the given input symbol
+    /// {@code t}. If {@code t} does not lead to a valid DFA state, this method
+    /// returns <seealso cref="#ERROR"/>. </returns>
+    virtual dfa::DFAState *computeTargetState(dfa::DFA &dfa, dfa::DFAState *previousD, size_t t);
+
+    virtual void predicateDFAState(dfa::DFAState *dfaState, DecisionState *decisionState);
+
+    // comes back with reach.uniqueAlt set to a valid alt
+    virtual size_t execATNWithFullContext(dfa::DFA &dfa, dfa::DFAState *D, ATNConfigSet *s0,
+                                          TokenStream *input, size_t startIndex, ParserRuleContext *outerContext); // how far we got before failing over
+
+    virtual std::unique_ptr<ATNConfigSet> computeReachSet(ATNConfigSet *closure, size_t t, bool fullCtx);
+
+    /// <summary>
+    /// Return a configuration set containing only the configurations from
+    /// {@code configs} which are in a <seealso cref="RuleStopState"/>. If all
+    /// configurations in {@code configs} are already in a rule stop state, this
+    /// method simply returns {@code configs}.
+    /// <p/>
+    /// When {@code lookToEndOfRule} is true, this method uses
+    /// <seealso cref="ATN#nextTokens"/> for each configuration in {@code configs} which is
+    /// not already in a rule stop state to see if a rule stop state is reachable
+    /// from the configuration via epsilon-only transitions.
+    /// </summary>
+    /// <param name="configs"> the configuration set to update </param>
+    /// <param name="lookToEndOfRule"> when true, this method checks for rule stop states
+    /// reachable by epsilon-only transitions from each configuration in
+    /// {@code configs}.
+    /// </param>
+    /// <returns> {@code configs} if all configurations in {@code configs} are in a
+    /// rule stop state, otherwise return a new configuration set containing only
+    /// the configurations from {@code configs} which are in a rule stop state </returns>
+    virtual ATNConfigSet* removeAllConfigsNotInRuleStopState(ATNConfigSet *configs, bool lookToEndOfRule);
+
+    virtual std::unique_ptr<ATNConfigSet> computeStartState(ATNState *p, RuleContext *ctx, bool fullCtx);
+
+    /* parrt internal source braindump that doesn't mess up
+     * external API spec.
+
+     applyPrecedenceFilter is an optimization to avoid highly
+     nonlinear prediction of expressions and other left recursive
+     rules. The precedence predicates such as {3>=prec}? Are highly
+     context-sensitive in that they can only be properly evaluated
+     in the context of the proper prec argument. Without pruning,
+     these predicates are normal predicates evaluated when we reach
+     conflict state (or unique prediction). As we cannot evaluate
+     these predicates out of context, the resulting conflict leads
+     to full LL evaluation and nonlinear prediction which shows up
+     very clearly with fairly large expressions.
+
+     Example grammar:
+
+     e : e '*' e
+     | e '+' e
+     | INT
+     ;
+
+     We convert that to the following:
+
+     e[int prec]
+     :   INT
+     ( {3>=prec}? '*' e[4]
+     | {2>=prec}? '+' e[3]
+     )*
+     ;
+
+     The (..)* loop has a decision for the inner block as well as
+     an enter or exit decision, which is what concerns us here. At
+     the 1st + of input 1+2+3, the loop entry sees both predicates
+     and the loop exit also sees both predicates by falling off the
+     edge of e.  This is because we have no stack information with
+     SLL and find the follow of e, which will hit the return states
+     inside the loop after e[4] and e[3], which brings it back to
+     the enter or exit decision. In this case, we know that we
+     cannot evaluate those predicates because we have fallen off
+     the edge of the stack and will in general not know which prec
+     parameter is the right one to use in the predicate.
+
+     Because we have special information, that these are precedence
+     predicates, we can resolve them without failing over to full
+     LL despite their context sensitive nature. We make an
+     assumption that prec[-1] <= prec[0], meaning that the current
+     precedence level is greater than or equal to the precedence
+     level of recursive invocations above us in the stack. For
+     example, if predicate {3>=prec}? is true of the current prec,
+     then one option is to enter the loop to match it now. The
+     other option is to exit the loop and the left recursive rule
+     to match the current operator in rule invocation further up
+     the stack. But, we know that all of those prec are lower or
+     the same value and so we can decide to enter the loop instead
+     of matching it later. That means we can strip out the other
+     configuration for the exit branch.
+
+     So imagine we have (14,1,$,{2>=prec}?) and then
+     (14,2,$-dipsIntoOuterContext,{2>=prec}?). The optimization
+     allows us to collapse these two configurations. We know that
+     if {2>=prec}? is true for the current prec parameter, it will
+     also be true for any prec from an invoking e call, indicated
+     by dipsIntoOuterContext. As the predicates are both true, we
+     have the option to evaluate them early in the decision start
+     state. We do this by stripping both predicates and choosing to
+     enter the loop as it is consistent with the notion of operator
+     precedence. It's also how the full LL conflict resolution
+     would work.
+
+     The solution requires a different DFA start state for each
+     precedence level.
+
+     The basic filter mechanism is to remove configurations of the
+     form (p, 2, pi) if (p, 1, pi) exists for the same p and pi. In
+     other words, for the same ATN state and predicate context,
+     remove any configuration associated with an exit branch if
+     there is a configuration associated with the enter branch.
+
+     It's also the case that the filter evaluates precedence
+     predicates and resolves conflicts according to precedence
+     levels. For example, for input 1+2+3 at the first +, we see
+     prediction filtering
+
+     [(11,1,[$],{3>=prec}?), (14,1,[$],{2>=prec}?), (5,2,[$],up=1),
+     (11,2,[$],up=1), (14,2,[$],up=1)],hasSemanticContext=true,dipsIntoOuterContext
+
+     to
+
+     [(11,1,[$]), (14,1,[$]), (5,2,[$],up=1)],dipsIntoOuterContext
+
+     This filters because {3>=prec}? evals to true and collapses
+     (11,1,[$],{3>=prec}?) and (11,2,[$],up=1) since early conflict
+     resolution based upon rules of operator precedence fits with
+     our usual match first alt upon conflict.
+
+     We noticed a problem where a recursive call resets precedence
+     to 0. Sam's fix: each config has flag indicating if it has
+     returned from an expr[0] call. then just don't filter any
+     config with that flag set. flag is carried along in
+     closure(). so to avoid adding field, set bit just under sign
+     bit of dipsIntoOuterContext (SUPPRESS_PRECEDENCE_FILTER).
+     With the change you filter "unless (p, 2, pi) was reached
+     after leaving the rule stop state of the LR rule containing
+     state p, corresponding to a rule invocation with precedence
+     level 0"
+     */
+
+    /**
+     * This method transforms the start state computed by
+     * {@link #computeStartState} to the special start state used by a
+     * precedence DFA for a particular precedence value. The transformation
+     * process applies the following changes to the start state's configuration
+     * set.
+     *
+     * <ol>
+     * <li>Evaluate the precedence predicates for each configuration using
+     * {@link SemanticContext#evalPrecedence}.</li>
+     * <li>When {@link ATNConfig#isPrecedenceFilterSuppressed} is {@code false},
+     * remove all configurations which predict an alternative greater than 1,
+     * for which another configuration that predicts alternative 1 is in the
+     * same ATN state with the same prediction context. This transformation is
+     * valid for the following reasons:
+     * <ul>
+     * <li>The closure block cannot contain any epsilon transitions which bypass
+     * the body of the closure, so all states reachable via alternative 1 are
+     * part of the precedence alternatives of the transformed left-recursive
+     * rule.</li>
+     * <li>The "primary" portion of a left recursive rule cannot contain an
+     * epsilon transition, so the only way an alternative other than 1 can exist
+     * in a state that is also reachable via alternative 1 is by nesting calls
+     * to the left-recursive rule, with the outer calls not being at the
+     * preferred precedence level. The
+     * {@link ATNConfig#isPrecedenceFilterSuppressed} property marks ATN
+     * configurations which do not meet this condition, and therefore are not
+     * eligible for elimination during the filtering process.</li>
+     * </ul>
+     * </li>
+     * </ol>
+     *
+     * <p>
+     * The prediction context must be considered by this filter to address
+     * situations like the following.
+     * </p>
+     * <code>
+     * <pre>
+     * grammar TA;
+     * prog: statement* EOF;
+     * statement: letterA | statement letterA 'b' ;
+     * letterA: 'a';
+     * </pre>
+     * </code>
+     * <p>
+     * If the above grammar, the ATN state immediately before the token
+     * reference {@code 'a'} in {@code letterA} is reachable from the left edge
+     * of both the primary and closure blocks of the left-recursive rule
+     * {@code statement}. The prediction context associated with each of these
+     * configurations distinguishes between them, and prevents the alternative
+     * which stepped out to {@code prog} (and then back in to {@code statement}
+     * from being eliminated by the filter.
+     * </p>
+     *
+     * @param configs The configuration set computed by
+     * {@link #computeStartState} as the start state for the DFA.
+     * @return The transformed configuration set representing the start state
+     * for a precedence DFA at a particular precedence level (determined by
+     * calling {@link Parser#getPrecedence}).
+     */
+    std::unique_ptr<ATNConfigSet> applyPrecedenceFilter(ATNConfigSet *configs);
+
+    virtual ATNState *getReachableTarget(Transition *trans, size_t ttype);
+
+    virtual std::vector<Ref<SemanticContext>> getPredsForAmbigAlts(const antlrcpp::BitSet &ambigAlts,
+                                                                   ATNConfigSet *configs, size_t nalts);
+
+    virtual std::vector<dfa::DFAState::PredPrediction*> getPredicatePredictions(const antlrcpp::BitSet &ambigAlts,
+                                                                                std::vector<Ref<SemanticContext>> const& altToPred);
+
+    /**
+     * This method is used to improve the localization of error messages by
+     * choosing an alternative rather than throwing a
+     * {@link NoViableAltException} in particular prediction scenarios where the
+     * {@link #ERROR} state was reached during ATN simulation.
+     *
+     * <p>
+     * The default implementation of this method uses the following
+     * algorithm to identify an ATN configuration which successfully parsed the
+     * decision entry rule. Choosing such an alternative ensures that the
+     * {@link ParserRuleContext} returned by the calling rule will be complete
+     * and valid, and the syntax error will be reported later at a more
+     * localized location.</p>
+     *
+     * <ul>
+     * <li>If a syntactically valid path or paths reach the end of the decision rule and
+     * they are semantically valid if predicated, return the min associated alt.</li>
+     * <li>Else, if a semantically invalid but syntactically valid path exist
+     * or paths exist, return the minimum associated alt.
+     * </li>
+     * <li>Otherwise, return {@link ATN#INVALID_ALT_NUMBER}.</li>
+     * </ul>
+     *
+     * <p>
+     * In some scenarios, the algorithm described above could predict an
+     * alternative which will result in a {@link FailedPredicateException} in
+     * the parser. Specifically, this could occur if the <em>only</em> configuration
+     * capable of successfully parsing to the end of the decision rule is
+     * blocked by a semantic predicate. By choosing this alternative within
+     * {@link #adaptivePredict} instead of throwing a
+     * {@link NoViableAltException}, the resulting
+     * {@link FailedPredicateException} in the parser will identify the specific
+     * predicate which is preventing the parser from successfully parsing the
+     * decision rule, which helps developers identify and correct logic errors
+     * in semantic predicates.
+     * </p>
+     *
+     * @param configs The ATN configurations which were valid immediately before
+     * the {@link #ERROR} state was reached
+     * @param outerContext The is the \gamma_0 initial parser context from the paper
+     * or the parser stack at the instant before prediction commences.
+     *
+     * @return The value to return from {@link #adaptivePredict}, or
+     * {@link ATN#INVALID_ALT_NUMBER} if a suitable alternative was not
+     * identified and {@link #adaptivePredict} should report an error instead.
+     */
+    size_t getSynValidOrSemInvalidAltThatFinishedDecisionEntryRule(ATNConfigSet *configs,
+                                                                   ParserRuleContext *outerContext);
+
+    virtual size_t getAltThatFinishedDecisionEntryRule(ATNConfigSet *configs);
+
+    /** Walk the list of configurations and split them according to
+     *  those that have preds evaluating to true/false.  If no pred, assume
+     *  true pred and include in succeeded set.  Returns Pair of sets.
+     *
+     *  Create a new set so as not to alter the incoming parameter.
+     *
+     *  Assumption: the input stream has been restored to the starting point
+     *  prediction, which is where predicates need to evaluate.
+     */
+    std::pair<ATNConfigSet *, ATNConfigSet *> splitAccordingToSemanticValidity(ATNConfigSet *configs,
+                                                                               ParserRuleContext *outerContext);
+
+    /// <summary>
+    /// Look through a list of predicate/alt pairs, returning alts for the
+    ///  pairs that win. A {@code NONE} predicate indicates an alt containing an
+    ///  unpredicated config which behaves as "always true." If !complete
+    ///  then we stop at the first predicate that evaluates to true. This
+    ///  includes pairs with null predicates.
+    /// </summary>
+    virtual antlrcpp::BitSet evalSemanticContext(std::vector<dfa::DFAState::PredPrediction*> predPredictions,
+                                                 ParserRuleContext *outerContext, bool complete);
+
+    /**
+     * Evaluate a semantic context within a specific parser context.
+     *
+     * <p>
+     * This method might not be called for every semantic context evaluated
+     * during the prediction process. In particular, we currently do not
+     * evaluate the following but it may change in the future:</p>
+     *
+     * <ul>
+     * <li>Precedence predicates (represented by
+     * {@link SemanticContext.PrecedencePredicate}) are not currently evaluated
+     * through this method.</li>
+     * <li>Operator predicates (represented by {@link SemanticContext.AND} and
+     * {@link SemanticContext.OR}) are evaluated as a single semantic
+     * context, rather than evaluating the operands individually.
+     * Implementations which require evaluation results from individual
+     * predicates should override this method to explicitly handle evaluation of
+     * the operands within operator predicates.</li>
+     * </ul>
+     *
+     * @param pred The semantic context to evaluate
+     * @param parserCallStack The parser context in which to evaluate the
+     * semantic context
+     * @param alt The alternative which is guarded by {@code pred}
+     * @param fullCtx {@code true} if the evaluation is occurring during LL
+     * prediction; otherwise, {@code false} if the evaluation is occurring
+     * during SLL prediction
+     *
+     * @since 4.3
+     */
+    virtual bool evalSemanticContext(Ref<SemanticContext> const& pred, ParserRuleContext *parserCallStack,
+                                     size_t alt, bool fullCtx);
+
+    /* TODO: If we are doing predicates, there is no point in pursuing
+     closure operations if we reach a DFA state that uniquely predicts
+     alternative. We will not be caching that DFA state and it is a
+     waste to pursue the closure. Might have to advance when we do
+     ambig detection thought :(
+     */
+    virtual void closure(Ref<ATNConfig> const& config, ATNConfigSet *configs, ATNConfig::Set &closureBusy,
+                         bool collectPredicates, bool fullCtx, bool treatEofAsEpsilon);
+
+    virtual void closureCheckingStopState(Ref<ATNConfig> const& config, ATNConfigSet *configs, ATNConfig::Set &closureBusy,
+                                          bool collectPredicates, bool fullCtx, int depth, bool treatEofAsEpsilon);
+    
+    /// Do the actual work of walking epsilon edges.
+    virtual void closure_(Ref<ATNConfig> const& config, ATNConfigSet *configs, ATNConfig::Set &closureBusy,
+                          bool collectPredicates, bool fullCtx, int depth, bool treatEofAsEpsilon);
+    
+    virtual Ref<ATNConfig> getEpsilonTarget(Ref<ATNConfig> const& config, Transition *t, bool collectPredicates,
+                                            bool inContext, bool fullCtx, bool treatEofAsEpsilon);
+    virtual Ref<ATNConfig> actionTransition(Ref<ATNConfig> const& config, ActionTransition *t);
+
+    virtual Ref<ATNConfig> predTransition(Ref<ATNConfig> const& config, PredicateTransition *pt, bool collectPredicates,
+                                          bool inContext, bool fullCtx);
+
+    virtual Ref<ATNConfig> ruleTransition(Ref<ATNConfig> const& config, RuleTransition *t);
+
+    /**
+     * Gets a {@link BitSet} containing the alternatives in {@code configs}
+     * which are part of one or more conflicting alternative subsets.
+     *
+     * @param configs The {@link ATNConfigSet} to analyze.
+     * @return The alternatives in {@code configs} which are part of one or more
+     * conflicting alternative subsets. If {@code configs} does not contain any
+     * conflicting subsets, this method returns an empty {@link BitSet}.
+     */
+    virtual antlrcpp::BitSet getConflictingAlts(ATNConfigSet *configs);
+
+    /// <summary>
+    /// Sam pointed out a problem with the previous definition, v3, of
+    /// ambiguous states. If we have another state associated with conflicting
+    /// alternatives, we should keep going. For example, the following grammar
+    ///
+    /// s : (ID | ID ID?) ';' ;
+    ///
+    /// When the ATN simulation reaches the state before ';', it has a DFA
+    /// state that looks like: [12|1|[], 6|2|[], 12|2|[]]. Naturally
+    /// 12|1|[] and 12|2|[] conflict, but we cannot stop processing this node
+    /// because alternative to has another way to continue, via [6|2|[]].
+    /// The key is that we have a single state that has config's only associated
+    /// with a single alternative, 2, and crucially the state transitions
+    /// among the configurations are all non-epsilon transitions. That means
+    /// we don't consider any conflicts that include alternative 2. So, we
+    /// ignore the conflict between alts 1 and 2. We ignore a set of
+    /// conflicting alts when there is an intersection with an alternative
+    /// associated with a single alt state in the state->config-list map.
+    ///
+    /// It's also the case that we might have two conflicting configurations but
+    /// also a 3rd nonconflicting configuration for a different alternative:
+    /// [1|1|[], 1|2|[], 8|3|[]]. This can come about from grammar:
+    ///
+    /// a : A | A | A B ;
+    ///
+    /// After matching input A, we reach the stop state for rule A, state 1.
+    /// State 8 is the state right before B. Clearly alternatives 1 and 2
+    /// conflict and no amount of further lookahead will separate the two.
+    /// However, alternative 3 will be able to continue and so we do not
+    /// stop working on this state. In the previous example, we're concerned
+    /// with states associated with the conflicting alternatives. Here alt
+    /// 3 is not associated with the conflicting configs, but since we can continue
+    /// looking for input reasonably, I don't declare the state done. We
+    /// ignore a set of conflicting alts when we have an alternative
+    /// that we still need to pursue.
+    /// </summary>
+
+    virtual antlrcpp::BitSet getConflictingAltsOrUniqueAlt(ATNConfigSet *configs);
+
+    virtual NoViableAltException noViableAlt(TokenStream *input, ParserRuleContext *outerContext,
+                                              ATNConfigSet *configs, size_t startIndex, bool deleteConfigs);
+
+    static size_t getUniqueAlt(ATNConfigSet *configs);
+
+    /// <summary>
+    /// Add an edge to the DFA, if possible. This method calls
+    /// <seealso cref="#addDFAState"/> to ensure the {@code to} state is present in the
+    /// DFA. If {@code from} is {@code null}, or if {@code t} is outside the
+    /// range of edges that can be represented in the DFA tables, this method
+    /// returns without adding the edge to the DFA.
+    /// <p/>
+    /// If {@code to} is {@code null}, this method returns {@code null}.
+    /// Otherwise, this method returns the <seealso cref="DFAState"/> returned by calling
+    /// <seealso cref="#addDFAState"/> for the {@code to} state.
+    /// </summary>
+    /// <param name="dfa"> The DFA </param>
+    /// <param name="from"> The source state for the edge </param>
+    /// <param name="t"> The input symbol </param>
+    /// <param name="to"> The target state for the edge
+    /// </param>
+    /// <returns> If {@code to} is {@code null}, this method returns {@code null};
+    /// otherwise this method returns the result of calling <seealso cref="#addDFAState"/>
+    /// on {@code to} </returns>
+    virtual dfa::DFAState *addDFAEdge(dfa::DFA &dfa, dfa::DFAState *from, ssize_t t, dfa::DFAState *to);
+
+    /// <summary>
+    /// Add state {@code D} to the DFA if it is not already present, and return
+    /// the actual instance stored in the DFA. If a state equivalent to {@code D}
+    /// is already in the DFA, the existing state is returned. Otherwise this
+    /// method returns {@code D} after adding it to the DFA.
+    /// <p/>
+    /// If {@code D} is <seealso cref="#ERROR"/>, this method returns <seealso cref="#ERROR"/> and
+    /// does not change the DFA.
+    /// </summary>
+    /// <param name="dfa"> The dfa </param>
+    /// <param name="D"> The DFA state to add </param>
+    /// <returns> The state stored in the DFA. This will be either the existing
+    /// state if {@code D} is already in the DFA, or {@code D} itself if the
+    /// state was not already present. </returns>
+    virtual dfa::DFAState *addDFAState(dfa::DFA &dfa, dfa::DFAState *D);
+
+    virtual void reportAttemptingFullContext(dfa::DFA &dfa, const antlrcpp::BitSet &conflictingAlts,
+      ATNConfigSet *configs, size_t startIndex, size_t stopIndex);
+
+    virtual void reportContextSensitivity(dfa::DFA &dfa, size_t prediction, ATNConfigSet *configs,
+                                          size_t startIndex, size_t stopIndex);
+
+    /// If context sensitive parsing, we know it's ambiguity not conflict.
+    virtual void reportAmbiguity(dfa::DFA &dfa,
+                                 dfa::DFAState *D, // the DFA state from execATN() that had SLL conflicts
+                                 size_t startIndex, size_t stopIndex,
+                                 bool exact,
+                                 const antlrcpp::BitSet &ambigAlts,
+                                 ATNConfigSet *configs); // configs that LL not SLL considered conflicting
+
+  private:
+    // SLL, LL, or LL + exact ambig detection?
+    PredictionMode _mode;
+
+    static bool getLrLoopSetting();
+    void InitializeInstanceFields();
+  };
+
+} // namespace atn
+} // namespace antlr4
+

lib/antlr4/include/atn/PlusBlockStartState.h

@@ -0,0 +1,25 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/BlockStartState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// Start of {@code (A|B|...)+} loop. Technically a decision state, but
+  /// we don't use for code generation; somebody might need it, so I'm defining
+  /// it for completeness. In reality, the <seealso cref="PlusLoopbackState"/> node is the
+  /// real decision-making note for {@code A+}.
+  class ANTLR4CPP_PUBLIC PlusBlockStartState final : public BlockStartState {
+  public:
+    PlusLoopbackState *loopBackState = nullptr;
+
+    virtual size_t getStateType() override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/PlusLoopbackState.h

@@ -0,0 +1,22 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// Decision state for {@code A+} and {@code (A|B)+}. It has two transitions:
+  /// one to the loop back to start of the block and one to exit.
+  class ANTLR4CPP_PUBLIC PlusLoopbackState final : public DecisionState {
+
+  public:
+    virtual size_t getStateType() override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/PrecedencePredicateTransition.h

@@ -0,0 +1,29 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/AbstractPredicateTransition.h"
+#include "SemanticContext.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC PrecedencePredicateTransition final : public AbstractPredicateTransition {
+  public:
+    const int precedence;
+
+    PrecedencePredicateTransition(ATNState *target, int precedence);
+
+    virtual SerializationType getSerializationType() const override;
+    virtual bool isEpsilon() const override;
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+    Ref<SemanticContext::PrecedencePredicate> getPredicate() const;
+    virtual std::string toString() const override;
+
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/PredicateEvalInfo.h

@@ -0,0 +1,62 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionEventInfo.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// This class represents profiling event information for semantic predicate
+  /// evaluations which occur during prediction.
+  /// </summary>
+  /// <seealso cref= ParserATNSimulator#evalSemanticContext
+  ///
+  /// @since 4.3 </seealso>
+  class ANTLR4CPP_PUBLIC PredicateEvalInfo : public DecisionEventInfo {
+  public:
+    /// The semantic context which was evaluated.
+    const Ref<SemanticContext> semctx;
+
+    /// <summary>
+    /// The alternative number for the decision which is guarded by the semantic
+    /// context <seealso cref="#semctx"/>. Note that other ATN
+    /// configurations may predict the same alternative which are guarded by
+    /// other semantic contexts and/or <seealso cref="SemanticContext#NONE"/>.
+    /// </summary>
+    const size_t predictedAlt;
+
+    /// The result of evaluating the semantic context <seealso cref="#semctx"/>.
+    const bool evalResult;
+
+    /// <summary>
+    /// Constructs a new instance of the <seealso cref="PredicateEvalInfo"/> class with the
+    /// specified detailed predicate evaluation information.
+    /// </summary>
+    /// <param name="decision"> The decision number </param>
+    /// <param name="input"> The input token stream </param>
+    /// <param name="startIndex"> The start index for the current prediction </param>
+    /// <param name="stopIndex"> The index at which the predicate evaluation was
+    /// triggered. Note that the input stream may be reset to other positions for
+    /// the actual evaluation of individual predicates. </param>
+    /// <param name="semctx"> The semantic context which was evaluated </param>
+    /// <param name="evalResult"> The results of evaluating the semantic context </param>
+    /// <param name="predictedAlt"> The alternative number for the decision which is
+    /// guarded by the semantic context {@code semctx}. See <seealso cref="#predictedAlt"/>
+    /// for more information. </param>
+    /// <param name="fullCtx"> {@code true} if the semantic context was
+    /// evaluated during LL prediction; otherwise, {@code false} if the semantic
+    /// context was evaluated during SLL prediction
+    /// </param>
+    /// <seealso cref= ParserATNSimulator#evalSemanticContext(SemanticContext, ParserRuleContext, int, boolean) </seealso>
+    /// <seealso cref= SemanticContext#eval(Recognizer, RuleContext) </seealso>
+    PredicateEvalInfo(size_t decision, TokenStream *input, size_t startIndex, size_t stopIndex,
+                      Ref<SemanticContext> const& semctx, bool evalResult, size_t predictedAlt, bool fullCtx);
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/PredicateTransition.h

@@ -0,0 +1,39 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/AbstractPredicateTransition.h"
+#include "SemanticContext.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// TODO: this is old comment:
+  ///  A tree of semantic predicates from the grammar AST if label==SEMPRED.
+  ///  In the ATN, labels will always be exactly one predicate, but the DFA
+  ///  may have to combine a bunch of them as it collects predicates from
+  ///  multiple ATN configurations into a single DFA state.
+  class ANTLR4CPP_PUBLIC PredicateTransition final : public AbstractPredicateTransition {
+  public:
+    const size_t ruleIndex;
+    const size_t predIndex;
+    const bool isCtxDependent; // e.g., $i ref in pred
+
+    PredicateTransition(ATNState *target, size_t ruleIndex, size_t predIndex, bool isCtxDependent);
+
+    virtual SerializationType getSerializationType() const override;
+
+    virtual bool isEpsilon() const override;
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+
+    Ref<SemanticContext::Predicate> getPredicate() const;
+
+    virtual std::string toString() const override;
+
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/PredictionContext.h

@@ -0,0 +1,254 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "Recognizer.h"
+#include "atn/ATN.h"
+#include "atn/ATNState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  struct PredictionContextHasher;
+  struct PredictionContextComparer;
+  class PredictionContextMergeCache;
+
+  typedef std::unordered_set<Ref<PredictionContext>, PredictionContextHasher, PredictionContextComparer> PredictionContextCache;
+
+  class ANTLR4CPP_PUBLIC PredictionContext {
+  public:
+    /// Represents $ in local context prediction, which means wildcard.
+    /// *+x = *.
+    static const Ref<PredictionContext> EMPTY;
+
+    /// Represents $ in an array in full context mode, when $
+    /// doesn't mean wildcard: $ + x = [$,x]. Here,
+    /// $ = EMPTY_RETURN_STATE.
+    // ml: originally Integer.MAX_VALUE, which would be -1 for us, but this is already used in places where
+    //     -1 is converted to unsigned, so we use a different value here. Any value does the job provided it doesn't
+    //     conflict with real return states.
+    static const size_t EMPTY_RETURN_STATE = static_cast<size_t>(-10); // std::numeric_limits<size_t>::max() - 9;
+
+  private:
+    static const size_t INITIAL_HASH = 1;
+
+  public:
+    static size_t globalNodeCount;
+    const size_t id;
+
+    /// <summary>
+    /// Stores the computed hash code of this <seealso cref="PredictionContext"/>. The hash
+    /// code is computed in parts to match the following reference algorithm.
+    ///
+    /// <pre>
+    ///  private int referenceHashCode() {
+    ///      int hash = <seealso cref="MurmurHash#initialize"/>(<seealso cref="#INITIAL_HASH"/>);
+    ///
+    ///      for (int i = 0; i < <seealso cref="#size()"/>; i++) {
+    ///          hash = <seealso cref="MurmurHash#update"/>(hash, <seealso cref="#getParent"/>(i));
+    ///      }
+    ///
+    ///      for (int i = 0; i < <seealso cref="#size()"/>; i++) {
+    ///          hash = <seealso cref="MurmurHash#update"/>(hash, <seealso cref="#getReturnState"/>(i));
+    ///      }
+    ///
+    ///      hash = <seealso cref="MurmurHash#finish"/>(hash, 2 * <seealso cref="#size()"/>);
+    ///      return hash;
+    ///  }
+    /// </pre>
+    /// </summary>
+    const size_t cachedHashCode;
+
+  protected:
+    PredictionContext(size_t cachedHashCode);
+    ~PredictionContext();
+
+  public:
+    /// Convert a RuleContext tree to a PredictionContext graph.
+    /// Return EMPTY if outerContext is empty.
+    static Ref<PredictionContext> fromRuleContext(const ATN &atn, RuleContext *outerContext);
+
+    virtual size_t size() const = 0;
+    virtual Ref<PredictionContext> getParent(size_t index) const = 0;
+    virtual size_t getReturnState(size_t index) const = 0;
+
+    virtual bool operator == (const PredictionContext &o) const = 0;
+
+    /// This means only the EMPTY (wildcard? not sure) context is in set.
+    virtual bool isEmpty() const;
+    virtual bool hasEmptyPath() const;
+    virtual size_t hashCode() const;
+
+  protected:
+    static size_t calculateEmptyHashCode();
+    static size_t calculateHashCode(Ref<PredictionContext> parent, size_t returnState);
+    static size_t calculateHashCode(const std::vector<Ref<PredictionContext>> &parents,
+                                    const std::vector<size_t> &returnStates);
+
+  public:
+    // dispatch
+    static Ref<PredictionContext> merge(const Ref<PredictionContext> &a, const Ref<PredictionContext> &b,
+                                        bool rootIsWildcard, PredictionContextMergeCache *mergeCache);
+
+    /// <summary>
+    /// Merge two <seealso cref="SingletonPredictionContext"/> instances.
+    ///
+    /// <p/>
+    ///
+    /// Stack tops equal, parents merge is same; return left graph.<br/>
+    /// <embed src="images/SingletonMerge_SameRootSamePar.svg" type="image/svg+xml"/>
+    ///
+    /// <p/>
+    ///
+    /// Same stack top, parents differ; merge parents giving array node, then
+    /// remainders of those graphs. A new root node is created to point to the
+    /// merged parents.<br/>
+    /// <embed src="images/SingletonMerge_SameRootDiffPar.svg" type="image/svg+xml"/>
+    ///
+    /// <p/>
+    ///
+    /// Different stack tops pointing to same parent. Make array node for the
+    /// root where both element in the root point to the same (original)
+    /// parent.<br/>
+    /// <embed src="images/SingletonMerge_DiffRootSamePar.svg" type="image/svg+xml"/>
+    ///
+    /// <p/>
+    ///
+    /// Different stack tops pointing to different parents. Make array node for
+    /// the root where each element points to the corresponding original
+    /// parent.<br/>
+    /// <embed src="images/SingletonMerge_DiffRootDiffPar.svg" type="image/svg+xml"/>
+    /// </summary>
+    /// <param name="a"> the first <seealso cref="SingletonPredictionContext"/> </param>
+    /// <param name="b"> the second <seealso cref="SingletonPredictionContext"/> </param>
+    /// <param name="rootIsWildcard"> {@code true} if this is a local-context merge,
+    /// otherwise false to indicate a full-context merge </param>
+    /// <param name="mergeCache"> </param>
+    static Ref<PredictionContext> mergeSingletons(const Ref<SingletonPredictionContext> &a,
+      const Ref<SingletonPredictionContext> &b, bool rootIsWildcard, PredictionContextMergeCache *mergeCache);
+
+    /**
+     * Handle case where at least one of {@code a} or {@code b} is
+     * {@link #EMPTY}. In the following diagrams, the symbol {@code $} is used
+     * to represent {@link #EMPTY}.
+     *
+     * <h2>Local-Context Merges</h2>
+     *
+     * <p>These local-context merge operations are used when {@code rootIsWildcard}
+     * is true.</p>
+     *
+     * <p>{@link #EMPTY} is superset of any graph; return {@link #EMPTY}.<br>
+     * <embed src="images/LocalMerge_EmptyRoot.svg" type="image/svg+xml"/></p>
+     *
+     * <p>{@link #EMPTY} and anything is {@code #EMPTY}, so merged parent is
+     * {@code #EMPTY}; return left graph.<br>
+     * <embed src="images/LocalMerge_EmptyParent.svg" type="image/svg+xml"/></p>
+     *
+     * <p>Special case of last merge if local context.<br>
+     * <embed src="images/LocalMerge_DiffRoots.svg" type="image/svg+xml"/></p>
+     *
+     * <h2>Full-Context Merges</h2>
+     *
+     * <p>These full-context merge operations are used when {@code rootIsWildcard}
+     * is false.</p>
+     *
+     * <p><embed src="images/FullMerge_EmptyRoots.svg" type="image/svg+xml"/></p>
+     *
+     * <p>Must keep all contexts; {@link #EMPTY} in array is a special value (and
+     * null parent).<br>
+     * <embed src="images/FullMerge_EmptyRoot.svg" type="image/svg+xml"/></p>
+     *
+     * <p><embed src="images/FullMerge_SameRoot.svg" type="image/svg+xml"/></p>
+     *
+     * @param a the first {@link SingletonPredictionContext}
+     * @param b the second {@link SingletonPredictionContext}
+     * @param rootIsWildcard {@code true} if this is a local-context merge,
+     * otherwise false to indicate a full-context merge
+     */
+    static Ref<PredictionContext> mergeRoot(const Ref<SingletonPredictionContext> &a,
+      const Ref<SingletonPredictionContext> &b, bool rootIsWildcard);
+
+    /**
+     * Merge two {@link ArrayPredictionContext} instances.
+     *
+     * <p>Different tops, different parents.<br>
+     * <embed src="images/ArrayMerge_DiffTopDiffPar.svg" type="image/svg+xml"/></p>
+     *
+     * <p>Shared top, same parents.<br>
+     * <embed src="images/ArrayMerge_ShareTopSamePar.svg" type="image/svg+xml"/></p>
+     *
+     * <p>Shared top, different parents.<br>
+     * <embed src="images/ArrayMerge_ShareTopDiffPar.svg" type="image/svg+xml"/></p>
+     *
+     * <p>Shared top, all shared parents.<br>
+     * <embed src="images/ArrayMerge_ShareTopSharePar.svg" type="image/svg+xml"/></p>
+     *
+     * <p>Equal tops, merge parents and reduce top to
+     * {@link SingletonPredictionContext}.<br>
+     * <embed src="images/ArrayMerge_EqualTop.svg" type="image/svg+xml"/></p>
+     */
+    static Ref<PredictionContext> mergeArrays(const Ref<ArrayPredictionContext> &a,
+      const Ref<ArrayPredictionContext> &b, bool rootIsWildcard, PredictionContextMergeCache *mergeCache);
+
+  protected:
+    /// Make pass over all M parents; merge any equal() ones.
+    /// @returns true if the list has been changed (i.e. duplicates where found).
+    static bool combineCommonParents(std::vector<Ref<PredictionContext>> &parents);
+
+  public:
+    static std::string toDOTString(const Ref<PredictionContext> &context);
+
+    static Ref<PredictionContext> getCachedContext(const Ref<PredictionContext> &context,
+      PredictionContextCache &contextCache,
+      std::map<Ref<PredictionContext>, Ref<PredictionContext>> &visited);
+
+    // ter's recursive version of Sam's getAllNodes()
+    static std::vector<Ref<PredictionContext>> getAllContextNodes(const Ref<PredictionContext> &context);
+    static void getAllContextNodes_(const Ref<PredictionContext> &context,
+      std::vector<Ref<PredictionContext>> &nodes, std::set<PredictionContext *> &visited);
+
+    virtual std::string toString() const;
+    virtual std::string toString(Recognizer *recog) const;
+
+    std::vector<std::string> toStrings(Recognizer *recognizer, int currentState);
+    std::vector<std::string> toStrings(Recognizer *recognizer, const Ref<PredictionContext> &stop, int currentState);
+  };
+
+  struct PredictionContextHasher {
+    size_t operator () (const Ref<PredictionContext> &k) const {
+      return k->hashCode();
+    }
+  };
+
+  struct PredictionContextComparer {
+    bool operator () (const Ref<PredictionContext> &lhs, const Ref<PredictionContext> &rhs) const
+    {
+      if (lhs == rhs) // Object identity.
+        return true;
+      return (lhs->hashCode() == rhs->hashCode()) && (*lhs == *rhs);
+    }
+  };
+
+  class PredictionContextMergeCache {
+  public:
+    Ref<PredictionContext> put(Ref<PredictionContext> const& key1, Ref<PredictionContext> const& key2,
+                               Ref<PredictionContext> const& value);
+    Ref<PredictionContext> get(Ref<PredictionContext> const& key1, Ref<PredictionContext> const& key2);
+
+    void clear();
+    std::string toString() const;
+    size_t count() const;
+
+  private:
+    std::unordered_map<Ref<PredictionContext>,
+      std::unordered_map<Ref<PredictionContext>, Ref<PredictionContext>, PredictionContextHasher, PredictionContextComparer>,
+      PredictionContextHasher, PredictionContextComparer> _data;
+
+  };
+
+} // namespace atn
+} // namespace antlr4
+

lib/antlr4/include/atn/PredictionMode.h

@@ -0,0 +1,436 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "support/BitSet.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /**
+   * This enumeration defines the prediction modes available in ANTLR 4 along with
+   * utility methods for analyzing configuration sets for conflicts and/or
+   * ambiguities.
+   */
+  enum class PredictionMode {
+    /**
+     * The SLL(*) prediction mode. This prediction mode ignores the current
+     * parser context when making predictions. This is the fastest prediction
+     * mode, and provides correct results for many grammars. This prediction
+     * mode is more powerful than the prediction mode provided by ANTLR 3, but
+     * may result in syntax errors for grammar and input combinations which are
+     * not SLL.
+     *
+     * <p>
+     * When using this prediction mode, the parser will either return a correct
+     * parse tree (i.e. the same parse tree that would be returned with the
+     * {@link #LL} prediction mode), or it will report a syntax error. If a
+     * syntax error is encountered when using the {@link #SLL} prediction mode,
+     * it may be due to either an actual syntax error in the input or indicate
+     * that the particular combination of grammar and input requires the more
+     * powerful {@link #LL} prediction abilities to complete successfully.</p>
+     *
+     * <p>
+     * This prediction mode does not provide any guarantees for prediction
+     * behavior for syntactically-incorrect inputs.</p>
+     */
+    SLL,
+
+    /**
+     * The LL(*) prediction mode. This prediction mode allows the current parser
+     * context to be used for resolving SLL conflicts that occur during
+     * prediction. This is the fastest prediction mode that guarantees correct
+     * parse results for all combinations of grammars with syntactically correct
+     * inputs.
+     *
+     * <p>
+     * When using this prediction mode, the parser will make correct decisions
+     * for all syntactically-correct grammar and input combinations. However, in
+     * cases where the grammar is truly ambiguous this prediction mode might not
+     * report a precise answer for <em>exactly which</em> alternatives are
+     * ambiguous.</p>
+     *
+     * <p>
+     * This prediction mode does not provide any guarantees for prediction
+     * behavior for syntactically-incorrect inputs.</p>
+     */
+    LL,
+
+    /**
+     * The LL(*) prediction mode with exact ambiguity detection. In addition to
+     * the correctness guarantees provided by the {@link #LL} prediction mode,
+     * this prediction mode instructs the prediction algorithm to determine the
+     * complete and exact set of ambiguous alternatives for every ambiguous
+     * decision encountered while parsing.
+     *
+     * <p>
+     * This prediction mode may be used for diagnosing ambiguities during
+     * grammar development. Due to the performance overhead of calculating sets
+     * of ambiguous alternatives, this prediction mode should be avoided when
+     * the exact results are not necessary.</p>
+     *
+     * <p>
+     * This prediction mode does not provide any guarantees for prediction
+     * behavior for syntactically-incorrect inputs.</p>
+     */
+    LL_EXACT_AMBIG_DETECTION
+  };
+
+  class ANTLR4CPP_PUBLIC PredictionModeClass {
+  public:
+    /**
+     * Computes the SLL prediction termination condition.
+     *
+     * <p>
+     * This method computes the SLL prediction termination condition for both of
+     * the following cases.</p>
+     *
+     * <ul>
+     * <li>The usual SLL+LL fallback upon SLL conflict</li>
+     * <li>Pure SLL without LL fallback</li>
+     * </ul>
+     *
+     * <p><strong>COMBINED SLL+LL PARSING</strong></p>
+     *
+     * <p>When LL-fallback is enabled upon SLL conflict, correct predictions are
+     * ensured regardless of how the termination condition is computed by this
+     * method. Due to the substantially higher cost of LL prediction, the
+     * prediction should only fall back to LL when the additional lookahead
+     * cannot lead to a unique SLL prediction.</p>
+     *
+     * <p>Assuming combined SLL+LL parsing, an SLL configuration set with only
+     * conflicting subsets should fall back to full LL, even if the
+     * configuration sets don't resolve to the same alternative (e.g.
+     * {@code {1,2}} and {@code {3,4}}. If there is at least one non-conflicting
+     * configuration, SLL could continue with the hopes that more lookahead will
+     * resolve via one of those non-conflicting configurations.</p>
+     *
+     * <p>Here's the prediction termination rule them: SLL (for SLL+LL parsing)
+     * stops when it sees only conflicting configuration subsets. In contrast,
+     * full LL keeps going when there is uncertainty.</p>
+     *
+     * <p><strong>HEURISTIC</strong></p>
+     *
+     * <p>As a heuristic, we stop prediction when we see any conflicting subset
+     * unless we see a state that only has one alternative associated with it.
+     * The single-alt-state thing lets prediction continue upon rules like
+     * (otherwise, it would admit defeat too soon):</p>
+     *
+     * <p>{@code [12|1|[], 6|2|[], 12|2|[]]. s : (ID | ID ID?) ';' ;}</p>
+     *
+     * <p>When the ATN simulation reaches the state before {@code ';'}, it has a
+     * DFA state that looks like: {@code [12|1|[], 6|2|[], 12|2|[]]}. Naturally
+     * {@code 12|1|[]} and {@code 12|2|[]} conflict, but we cannot stop
+     * processing this node because alternative to has another way to continue,
+     * via {@code [6|2|[]]}.</p>
+     *
+     * <p>It also let's us continue for this rule:</p>
+     *
+     * <p>{@code [1|1|[], 1|2|[], 8|3|[]] a : A | A | A B ;}</p>
+     *
+     * <p>After matching input A, we reach the stop state for rule A, state 1.
+     * State 8 is the state right before B. Clearly alternatives 1 and 2
+     * conflict and no amount of further lookahead will separate the two.
+     * However, alternative 3 will be able to continue and so we do not stop
+     * working on this state. In the previous example, we're concerned with
+     * states associated with the conflicting alternatives. Here alt 3 is not
+     * associated with the conflicting configs, but since we can continue
+     * looking for input reasonably, don't declare the state done.</p>
+     *
+     * <p><strong>PURE SLL PARSING</strong></p>
+     *
+     * <p>To handle pure SLL parsing, all we have to do is make sure that we
+     * combine stack contexts for configurations that differ only by semantic
+     * predicate. From there, we can do the usual SLL termination heuristic.</p>
+     *
+     * <p><strong>PREDICATES IN SLL+LL PARSING</strong></p>
+     *
+     * <p>SLL decisions don't evaluate predicates until after they reach DFA stop
+     * states because they need to create the DFA cache that works in all
+     * semantic situations. In contrast, full LL evaluates predicates collected
+     * during start state computation so it can ignore predicates thereafter.
+     * This means that SLL termination detection can totally ignore semantic
+     * predicates.</p>
+     *
+     * <p>Implementation-wise, {@link ATNConfigSet} combines stack contexts but not
+     * semantic predicate contexts so we might see two configurations like the
+     * following.</p>
+     *
+     * <p>{@code (s, 1, x, {}), (s, 1, x', {p})}</p>
+     *
+     * <p>Before testing these configurations against others, we have to merge
+     * {@code x} and {@code x'} (without modifying the existing configurations).
+     * For example, we test {@code (x+x')==x''} when looking for conflicts in
+     * the following configurations.</p>
+     *
+     * <p>{@code (s, 1, x, {}), (s, 1, x', {p}), (s, 2, x'', {})}</p>
+     *
+     * <p>If the configuration set has predicates (as indicated by
+     * {@link ATNConfigSet#hasSemanticContext}), this algorithm makes a copy of
+     * the configurations to strip out all of the predicates so that a standard
+     * {@link ATNConfigSet} will merge everything ignoring predicates.</p>
+     */
+    static bool hasSLLConflictTerminatingPrediction(PredictionMode mode, ATNConfigSet *configs);
+
+    /// <summary>
+    /// Checks if any configuration in {@code configs} is in a
+    /// <seealso cref="RuleStopState"/>. Configurations meeting this condition have
+    /// reached
+    /// the end of the decision rule (local context) or end of start rule (full
+    /// context).
+    /// </summary>
+    /// <param name="configs"> the configuration set to test </param>
+    /// <returns> {@code true} if any configuration in {@code configs} is in a
+    /// <seealso cref="RuleStopState"/>, otherwise {@code false} </returns>
+    static bool hasConfigInRuleStopState(ATNConfigSet *configs);
+
+    /// <summary>
+    /// Checks if all configurations in {@code configs} are in a
+    /// <seealso cref="RuleStopState"/>. Configurations meeting this condition have
+    /// reached
+    /// the end of the decision rule (local context) or end of start rule (full
+    /// context).
+    /// </summary>
+    /// <param name="configs"> the configuration set to test </param>
+    /// <returns> {@code true} if all configurations in {@code configs} are in a
+    /// <seealso cref="RuleStopState"/>, otherwise {@code false} </returns>
+    static bool allConfigsInRuleStopStates(ATNConfigSet *configs);
+
+    /**
+     * Full LL prediction termination.
+     *
+     * <p>Can we stop looking ahead during ATN simulation or is there some
+     * uncertainty as to which alternative we will ultimately pick, after
+     * consuming more input? Even if there are partial conflicts, we might know
+     * that everything is going to resolve to the same minimum alternative. That
+     * means we can stop since no more lookahead will change that fact. On the
+     * other hand, there might be multiple conflicts that resolve to different
+     * minimums. That means we need more look ahead to decide which of those
+     * alternatives we should predict.</p>
+     *
+     * <p>The basic idea is to split the set of configurations {@code C}, into
+     * conflicting subsets {@code (s, _, ctx, _)} and singleton subsets with
+     * non-conflicting configurations. Two configurations conflict if they have
+     * identical {@link ATNConfig#state} and {@link ATNConfig#context} values
+     * but different {@link ATNConfig#alt} value, e.g. {@code (s, i, ctx, _)}
+     * and {@code (s, j, ctx, _)} for {@code i!=j}.</p>
+     *
+     * <p>Reduce these configuration subsets to the set of possible alternatives.
+     * You can compute the alternative subsets in one pass as follows:</p>
+     *
+     * <p>{@code A_s,ctx = {i | (s, i, ctx, _)}} for each configuration in
+     * {@code C} holding {@code s} and {@code ctx} fixed.</p>
+     *
+     * <p>Or in pseudo-code, for each configuration {@code c} in {@code C}:</p>
+     *
+     * <pre>
+     * map[c] U= c.{@link ATNConfig#alt alt} # map hash/equals uses s and x, not
+     * alt and not pred
+     * </pre>
+     *
+     * <p>The values in {@code map} are the set of {@code A_s,ctx} sets.</p>
+     *
+     * <p>If {@code |A_s,ctx|=1} then there is no conflict associated with
+     * {@code s} and {@code ctx}.</p>
+     *
+     * <p>Reduce the subsets to singletons by choosing a minimum of each subset. If
+     * the union of these alternative subsets is a singleton, then no amount of
+     * more lookahead will help us. We will always pick that alternative. If,
+     * however, there is more than one alternative, then we are uncertain which
+     * alternative to predict and must continue looking for resolution. We may
+     * or may not discover an ambiguity in the future, even if there are no
+     * conflicting subsets this round.</p>
+     *
+     * <p>The biggest sin is to terminate early because it means we've made a
+     * decision but were uncertain as to the eventual outcome. We haven't used
+     * enough lookahead. On the other hand, announcing a conflict too late is no
+     * big deal; you will still have the conflict. It's just inefficient. It
+     * might even look until the end of file.</p>
+     *
+     * <p>No special consideration for semantic predicates is required because
+     * predicates are evaluated on-the-fly for full LL prediction, ensuring that
+     * no configuration contains a semantic context during the termination
+     * check.</p>
+     *
+     * <p><strong>CONFLICTING CONFIGS</strong></p>
+     *
+     * <p>Two configurations {@code (s, i, x)} and {@code (s, j, x')}, conflict
+     * when {@code i!=j} but {@code x=x'}. Because we merge all
+     * {@code (s, i, _)} configurations together, that means that there are at
+     * most {@code n} configurations associated with state {@code s} for
+     * {@code n} possible alternatives in the decision. The merged stacks
+     * complicate the comparison of configuration contexts {@code x} and
+     * {@code x'}. Sam checks to see if one is a subset of the other by calling
+     * merge and checking to see if the merged result is either {@code x} or
+     * {@code x'}. If the {@code x} associated with lowest alternative {@code i}
+     * is the superset, then {@code i} is the only possible prediction since the
+     * others resolve to {@code min(i)} as well. However, if {@code x} is
+     * associated with {@code j>i} then at least one stack configuration for
+     * {@code j} is not in conflict with alternative {@code i}. The algorithm
+     * should keep going, looking for more lookahead due to the uncertainty.</p>
+     *
+     * <p>For simplicity, I'm doing a equality check between {@code x} and
+     * {@code x'} that lets the algorithm continue to consume lookahead longer
+     * than necessary. The reason I like the equality is of course the
+     * simplicity but also because that is the test you need to detect the
+     * alternatives that are actually in conflict.</p>
+     *
+     * <p><strong>CONTINUE/STOP RULE</strong></p>
+     *
+     * <p>Continue if union of resolved alternative sets from non-conflicting and
+     * conflicting alternative subsets has more than one alternative. We are
+     * uncertain about which alternative to predict.</p>
+     *
+     * <p>The complete set of alternatives, {@code [i for (_,i,_)]}, tells us which
+     * alternatives are still in the running for the amount of input we've
+     * consumed at this point. The conflicting sets let us to strip away
+     * configurations that won't lead to more states because we resolve
+     * conflicts to the configuration with a minimum alternate for the
+     * conflicting set.</p>
+     *
+     * <p><strong>CASES</strong></p>
+     *
+     * <ul>
+     *
+     * <li>no conflicts and more than 1 alternative in set =&gt; continue</li>
+     *
+     * <li> {@code (s, 1, x)}, {@code (s, 2, x)}, {@code (s, 3, z)},
+     * {@code (s', 1, y)}, {@code (s', 2, y)} yields non-conflicting set
+     * {@code {3}} U conflicting sets {@code min({1,2})} U {@code min({1,2})} =
+     * {@code {1,3}} =&gt; continue
+     * </li>
+     *
+     * <li>{@code (s, 1, x)}, {@code (s, 2, x)}, {@code (s', 1, y)},
+     * {@code (s', 2, y)}, {@code (s'', 1, z)} yields non-conflicting set
+     * {@code {1}} U conflicting sets {@code min({1,2})} U {@code min({1,2})} =
+     * {@code {1}} =&gt; stop and predict 1</li>
+     *
+     * <li>{@code (s, 1, x)}, {@code (s, 2, x)}, {@code (s', 1, y)},
+     * {@code (s', 2, y)} yields conflicting, reduced sets {@code {1}} U
+     * {@code {1}} = {@code {1}} =&gt; stop and predict 1, can announce
+     * ambiguity {@code {1,2}}</li>
+     *
+     * <li>{@code (s, 1, x)}, {@code (s, 2, x)}, {@code (s', 2, y)},
+     * {@code (s', 3, y)} yields conflicting, reduced sets {@code {1}} U
+     * {@code {2}} = {@code {1,2}} =&gt; continue</li>
+     *
+     * <li>{@code (s, 1, x)}, {@code (s, 2, x)}, {@code (s', 3, y)},
+     * {@code (s', 4, y)} yields conflicting, reduced sets {@code {1}} U
+     * {@code {3}} = {@code {1,3}} =&gt; continue</li>
+     *
+     * </ul>
+     *
+     * <p><strong>EXACT AMBIGUITY DETECTION</strong></p>
+     *
+     * <p>If all states report the same conflicting set of alternatives, then we
+     * know we have the exact ambiguity set.</p>
+     *
+     * <p><code>|A_<em>i</em>|&gt;1</code> and
+     * <code>A_<em>i</em> = A_<em>j</em></code> for all <em>i</em>, <em>j</em>.</p>
+     *
+     * <p>In other words, we continue examining lookahead until all {@code A_i}
+     * have more than one alternative and all {@code A_i} are the same. If
+     * {@code A={{1,2}, {1,3}}}, then regular LL prediction would terminate
+     * because the resolved set is {@code {1}}. To determine what the real
+     * ambiguity is, we have to know whether the ambiguity is between one and
+     * two or one and three so we keep going. We can only stop prediction when
+     * we need exact ambiguity detection when the sets look like
+     * {@code A={{1,2}}} or {@code {{1,2},{1,2}}}, etc...</p>
+     */
+    static size_t resolvesToJustOneViableAlt(const std::vector<antlrcpp::BitSet> &altsets);
+
+    /// <summary>
+    /// Determines if every alternative subset in {@code altsets} contains more
+    /// than one alternative.
+    /// </summary>
+    /// <param name="altsets"> a collection of alternative subsets </param>
+    /// <returns> {@code true} if every <seealso cref="BitSet"/> in {@code altsets}
+    /// has
+    /// <seealso cref="BitSet#cardinality cardinality"/> &gt; 1, otherwise {@code
+    /// false} </returns>
+    static bool allSubsetsConflict(const std::vector<antlrcpp::BitSet> &altsets);
+
+    /// <summary>
+    /// Determines if any single alternative subset in {@code altsets} contains
+    /// exactly one alternative.
+    /// </summary>
+    /// <param name="altsets"> a collection of alternative subsets </param>
+    /// <returns> {@code true} if {@code altsets} contains a <seealso
+    /// cref="BitSet"/> with
+    /// <seealso cref="BitSet#cardinality cardinality"/> 1, otherwise {@code false}
+    /// </returns>
+    static bool hasNonConflictingAltSet(const std::vector<antlrcpp::BitSet> &altsets);
+
+    /// <summary>
+    /// Determines if any single alternative subset in {@code altsets} contains
+    /// more than one alternative.
+    /// </summary>
+    /// <param name="altsets"> a collection of alternative subsets </param>
+    /// <returns> {@code true} if {@code altsets} contains a <seealso
+    /// cref="BitSet"/> with
+    /// <seealso cref="BitSet#cardinality cardinality"/> &gt; 1, otherwise {@code
+    /// false} </returns>
+    static bool hasConflictingAltSet(const std::vector<antlrcpp::BitSet> &altsets);
+
+    /// <summary>
+    /// Determines if every alternative subset in {@code altsets} is equivalent.
+    /// </summary>
+    /// <param name="altsets"> a collection of alternative subsets </param>
+    /// <returns> {@code true} if every member of {@code altsets} is equal to the
+    /// others, otherwise {@code false} </returns>
+    static bool allSubsetsEqual(const std::vector<antlrcpp::BitSet> &altsets);
+
+    /// <summary>
+    /// Returns the unique alternative predicted by all alternative subsets in
+    /// {@code altsets}. If no such alternative exists, this method returns
+    /// <seealso cref="ATN#INVALID_ALT_NUMBER"/>.
+    /// </summary>
+    /// <param name="altsets"> a collection of alternative subsets </param>
+    static size_t getUniqueAlt(const std::vector<antlrcpp::BitSet> &altsets);
+
+    /// <summary>
+    /// Gets the complete set of represented alternatives for a collection of
+    /// alternative subsets. This method returns the union of each <seealso
+    /// cref="BitSet"/>
+    /// in {@code altsets}.
+    /// </summary>
+    /// <param name="altsets"> a collection of alternative subsets </param>
+    /// <returns> the set of represented alternatives in {@code altsets} </returns>
+    static antlrcpp::BitSet getAlts(const std::vector<antlrcpp::BitSet> &altsets);
+
+    /** Get union of all alts from configs. @since 4.5.1 */
+    static antlrcpp::BitSet getAlts(ATNConfigSet *configs);
+
+    /// <summary>
+    /// This function gets the conflicting alt subsets from a configuration set.
+    /// For each configuration {@code c} in {@code configs}:
+    ///
+    /// <pre>
+    /// map[c] U= c.<seealso cref="ATNConfig#alt alt"/> # map hash/equals uses s and
+    /// x, not
+    /// alt and not pred
+    /// </pre>
+    /// </summary>
+    static std::vector<antlrcpp::BitSet> getConflictingAltSubsets(ATNConfigSet *configs);
+
+    /// <summary>
+    /// Get a map from state to alt subset from a configuration set. For each
+    /// configuration {@code c} in {@code configs}:
+    ///
+    /// <pre>
+    /// map[c.<seealso cref="ATNConfig#state state"/>] U= c.<seealso
+    /// cref="ATNConfig#alt alt"/>
+    /// </pre>
+    /// </summary>
+    static std::map<ATNState*, antlrcpp::BitSet> getStateToAltMap(ATNConfigSet *configs);
+
+    static bool hasStateAssociatedWithOneAlt(ATNConfigSet *configs);
+
+    static size_t getSingleViableAlt(const std::vector<antlrcpp::BitSet> &altsets);
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/ProfilingATNSimulator.h

@@ -0,0 +1,60 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ParserATNSimulator.h"
+#include "atn/DecisionInfo.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC ProfilingATNSimulator : public ParserATNSimulator {
+  public:
+    ProfilingATNSimulator(Parser *parser);
+
+    virtual size_t adaptivePredict(TokenStream *input, size_t decision, ParserRuleContext *outerContext) override;
+
+    virtual std::vector<DecisionInfo> getDecisionInfo() const;
+    virtual dfa::DFAState* getCurrentState() const;
+
+  protected:
+    std::vector<DecisionInfo> _decisions;
+
+    int _sllStopIndex = 0;
+    int _llStopIndex = 0;
+
+    size_t _currentDecision = 0;
+    dfa::DFAState *_currentState;
+
+    /// <summary>
+    /// At the point of LL failover, we record how SLL would resolve the conflict so that
+    ///  we can determine whether or not a decision / input pair is context-sensitive.
+    ///  If LL gives a different result than SLL's predicted alternative, we have a
+    ///  context sensitivity for sure. The converse is not necessarily true, however.
+    ///  It's possible that after conflict resolution chooses minimum alternatives,
+    ///  SLL could get the same answer as LL. Regardless of whether or not the result indicates
+    ///  an ambiguity, it is not treated as a context sensitivity because LL prediction
+    ///  was not required in order to produce a correct prediction for this decision and input sequence.
+    ///  It may in fact still be a context sensitivity but we don't know by looking at the
+    ///  minimum alternatives for the current input.
+    /// </summary>
+    size_t conflictingAltResolvedBySLL = 0;
+
+    virtual dfa::DFAState* getExistingTargetState(dfa::DFAState *previousD, size_t t) override;
+    virtual dfa::DFAState* computeTargetState(dfa::DFA &dfa, dfa::DFAState *previousD, size_t t) override;
+    virtual std::unique_ptr<ATNConfigSet> computeReachSet(ATNConfigSet *closure, size_t t, bool fullCtx) override;
+    virtual bool evalSemanticContext(Ref<SemanticContext> const& pred, ParserRuleContext *parserCallStack,
+                                     size_t alt, bool fullCtx) override;
+    virtual void reportAttemptingFullContext(dfa::DFA &dfa, const antlrcpp::BitSet &conflictingAlts, ATNConfigSet *configs,
+                                             size_t startIndex, size_t stopIndex) override;
+    virtual void reportContextSensitivity(dfa::DFA &dfa, size_t prediction, ATNConfigSet *configs,
+                                          size_t startIndex, size_t stopIndex) override;
+    virtual void reportAmbiguity(dfa::DFA &dfa, dfa::DFAState *D, size_t startIndex, size_t stopIndex, bool exact,
+                                 const antlrcpp::BitSet &ambigAlts, ATNConfigSet *configs) override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/RangeTransition.h

@@ -0,0 +1,29 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/Transition.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC RangeTransition final : public Transition {
+  public:
+    const size_t from;
+    const size_t to;
+
+    RangeTransition(ATNState *target, size_t from, size_t to);
+
+    virtual SerializationType getSerializationType() const override;
+
+    virtual misc::IntervalSet label() const override;
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/RuleStartState.h

@@ -0,0 +1,25 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC RuleStartState final : public ATNState {
+  public:
+    RuleStartState();
+
+    RuleStopState *stopState = nullptr;
+    bool isLeftRecursiveRule = false;
+
+    virtual size_t getStateType() override;
+
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/RuleStopState.h

@@ -0,0 +1,25 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// The last node in the ATN for a rule, unless that rule is the start symbol.
+  /// In that case, there is one transition to EOF. Later, we might encode
+  /// references to all calls to this rule to compute FOLLOW sets for
+  /// error handling.
+  class ANTLR4CPP_PUBLIC RuleStopState final : public ATNState {
+
+  public:
+    virtual size_t getStateType() override;
+
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/RuleTransition.h

@@ -0,0 +1,40 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/Transition.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC RuleTransition : public Transition {
+  public:
+    /// Ptr to the rule definition object for this rule ref.
+    const size_t ruleIndex; // no Rule object at runtime
+
+    const int precedence;
+
+    /// What node to begin computations following ref to rule.
+    ATNState *followState;
+
+    /// @deprecated Use
+    /// <seealso cref="#RuleTransition(RuleStartState, size_t, int, ATNState)"/> instead.
+    RuleTransition(RuleStartState *ruleStart, size_t ruleIndex, ATNState *followState);
+
+    RuleTransition(RuleStartState *ruleStart, size_t ruleIndex, int precedence, ATNState *followState);
+    RuleTransition(RuleTransition const&) = delete;
+    RuleTransition& operator=(RuleTransition const&) = delete;
+
+    virtual SerializationType getSerializationType() const override;
+
+    virtual bool isEpsilon() const override;
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/SemanticContext.h

@@ -0,0 +1,222 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "Recognizer.h"
+#include "support/CPPUtils.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// A tree structure used to record the semantic context in which
+  ///  an ATN configuration is valid.  It's either a single predicate,
+  ///  a conjunction "p1 && p2", or a sum of products "p1||p2".
+  ///
+  ///  I have scoped the AND, OR, and Predicate subclasses of
+  ///  SemanticContext within the scope of this outer class.
+  class ANTLR4CPP_PUBLIC SemanticContext : public std::enable_shared_from_this<SemanticContext> {
+  public:
+    struct Hasher
+    {
+      size_t operator()(Ref<SemanticContext> const& k) const {
+        return k->hashCode();
+      }
+    };
+
+    struct Comparer {
+      bool operator()(Ref<SemanticContext> const& lhs, Ref<SemanticContext> const& rhs) const {
+        if (lhs == rhs)
+          return true;
+        return (lhs->hashCode() == rhs->hashCode()) && (*lhs == *rhs);
+      }
+    };
+
+
+    using Set = std::unordered_set<Ref<SemanticContext>, Hasher, Comparer>;
+
+    /**
+     * The default {@link SemanticContext}, which is semantically equivalent to
+     * a predicate of the form {@code {true}?}.
+     */
+    static const Ref<SemanticContext> NONE;
+
+    virtual ~SemanticContext();
+
+    virtual size_t hashCode() const = 0;
+    virtual std::string toString() const = 0;
+    virtual bool operator == (const SemanticContext &other) const = 0;
+    virtual bool operator != (const SemanticContext &other) const;
+
+    /// <summary>
+    /// For context independent predicates, we evaluate them without a local
+    /// context (i.e., null context). That way, we can evaluate them without
+    /// having to create proper rule-specific context during prediction (as
+    /// opposed to the parser, which creates them naturally). In a practical
+    /// sense, this avoids a cast exception from RuleContext to myruleContext.
+    /// <p/>
+    /// For context dependent predicates, we must pass in a local context so that
+    /// references such as $arg evaluate properly as _localctx.arg. We only
+    /// capture context dependent predicates in the context in which we begin
+    /// prediction, so we passed in the outer context here in case of context
+    /// dependent predicate evaluation.
+    /// </summary>
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) = 0;
+
+    /**
+     * Evaluate the precedence predicates for the context and reduce the result.
+     *
+     * @param parser The parser instance.
+     * @param parserCallStack
+     * @return The simplified semantic context after precedence predicates are
+     * evaluated, which will be one of the following values.
+     * <ul>
+     * <li>{@link #NONE}: if the predicate simplifies to {@code true} after
+     * precedence predicates are evaluated.</li>
+     * <li>{@code null}: if the predicate simplifies to {@code false} after
+     * precedence predicates are evaluated.</li>
+     * <li>{@code this}: if the semantic context is not changed as a result of
+     * precedence predicate evaluation.</li>
+     * <li>A non-{@code null} {@link SemanticContext}: the new simplified
+     * semantic context after precedence predicates are evaluated.</li>
+     * </ul>
+     */
+    virtual Ref<SemanticContext> evalPrecedence(Recognizer *parser, RuleContext *parserCallStack);
+
+    static Ref<SemanticContext> And(Ref<SemanticContext> const& a, Ref<SemanticContext> const& b);
+
+    /// See also: ParserATNSimulator::getPredsForAmbigAlts.
+    static Ref<SemanticContext> Or(Ref<SemanticContext> const& a, Ref<SemanticContext> const& b);
+
+    class Predicate;
+    class PrecedencePredicate;
+    class Operator;
+    class AND;
+    class OR;
+
+  private:
+    static std::vector<Ref<PrecedencePredicate>> filterPrecedencePredicates(const Set &collection);
+  };
+
+  class ANTLR4CPP_PUBLIC SemanticContext::Predicate : public SemanticContext {
+  public:
+    const size_t ruleIndex;
+    const size_t predIndex;
+    const bool isCtxDependent; // e.g., $i ref in pred
+
+  protected:
+    Predicate();
+
+  public:
+    Predicate(size_t ruleIndex, size_t predIndex, bool isCtxDependent);
+
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const SemanticContext &other) const override;
+    virtual std::string toString() const override;
+  };
+
+  class ANTLR4CPP_PUBLIC SemanticContext::PrecedencePredicate : public SemanticContext {
+  public:
+    const int precedence;
+
+  protected:
+    PrecedencePredicate();
+
+  public:
+    PrecedencePredicate(int precedence);
+
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual Ref<SemanticContext> evalPrecedence(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual int compareTo(PrecedencePredicate *o);
+    virtual size_t hashCode() const override;
+    virtual bool operator == (const SemanticContext &other) const override;
+    virtual std::string toString() const override;
+  };
+
+  /**
+   * This is the base class for semantic context "operators", which operate on
+   * a collection of semantic context "operands".
+   *
+   * @since 4.3
+   */
+  class ANTLR4CPP_PUBLIC SemanticContext::Operator : public SemanticContext {
+  public:
+    virtual ~Operator() override;
+
+    /**
+     * Gets the operands for the semantic context operator.
+     *
+     * @return a collection of {@link SemanticContext} operands for the
+     * operator.
+     *
+     * @since 4.3
+     */
+
+    virtual std::vector<Ref<SemanticContext>> getOperands() const = 0;
+  };
+
+  /**
+   * A semantic context which is true whenever none of the contained contexts
+   * is false.
+   */
+  class ANTLR4CPP_PUBLIC SemanticContext::AND : public SemanticContext::Operator {
+  public:
+    std::vector<Ref<SemanticContext>> opnds;
+
+    AND(Ref<SemanticContext> const& a, Ref<SemanticContext> const& b) ;
+
+    virtual std::vector<Ref<SemanticContext>> getOperands() const override;
+    virtual bool operator == (const SemanticContext &other) const override;
+    virtual size_t hashCode() const override;
+
+    /**
+     * The evaluation of predicates by this context is short-circuiting, but
+     * unordered.</p>
+     */
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual Ref<SemanticContext> evalPrecedence(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual std::string toString() const override;
+  };
+
+  /**
+   * A semantic context which is true whenever at least one of the contained
+   * contexts is true.
+   */
+  class ANTLR4CPP_PUBLIC SemanticContext::OR : public SemanticContext::Operator {
+  public:
+    std::vector<Ref<SemanticContext>> opnds;
+
+    OR(Ref<SemanticContext> const& a, Ref<SemanticContext> const& b);
+
+    virtual std::vector<Ref<SemanticContext>> getOperands() const override;
+    virtual bool operator == (const SemanticContext &other) const override;
+    virtual size_t hashCode() const override;
+
+    /**
+     * The evaluation of predicates by this context is short-circuiting, but
+     * unordered.
+     */
+    virtual bool eval(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual Ref<SemanticContext> evalPrecedence(Recognizer *parser, RuleContext *parserCallStack) override;
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4
+
+// Hash function for SemanticContext, used in the MurmurHash::update function
+
+namespace std {
+  using antlr4::atn::SemanticContext;
+
+  template <> struct hash<SemanticContext>
+  {
+    size_t operator () (SemanticContext &x) const
+    {
+      return x.hashCode();
+    }
+  };
+}

lib/antlr4/include/atn/SetTransition.h

@@ -0,0 +1,30 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/Transition.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// A transition containing a set of values. </summary>
+  class ANTLR4CPP_PUBLIC SetTransition : public Transition {
+  public:
+    const misc::IntervalSet set;
+
+    SetTransition(ATNState *target, const misc::IntervalSet &set);
+
+    virtual SerializationType getSerializationType() const override;
+
+    virtual misc::IntervalSet label() const override;
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/SingletonPredictionContext.h

@@ -0,0 +1,36 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/PredictionContext.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC SingletonPredictionContext : public PredictionContext {
+  public:
+    // Usually a parent is linked via a weak ptr. Not so here as we have kinda reverse reference chain.
+    // There are no child contexts stored here and often the parent context is left dangling when it's
+    // owning ATNState is released. In order to avoid having this context released as well (leaving all other contexts
+    // which got this one as parent with a null reference) we use a shared_ptr here instead, to keep those left alone
+    // parent contexts alive.
+    const Ref<PredictionContext> parent;
+    const size_t returnState;
+
+    SingletonPredictionContext(Ref<PredictionContext> const& parent, size_t returnState);
+    virtual ~SingletonPredictionContext();
+
+    static Ref<SingletonPredictionContext> create(Ref<PredictionContext> const& parent, size_t returnState);
+
+    virtual size_t size() const override;
+    virtual Ref<PredictionContext> getParent(size_t index) const override;
+    virtual size_t getReturnState(size_t index) const override;
+    virtual bool operator == (const PredictionContext &o) const override;
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/StarBlockStartState.h

@@ -0,0 +1,21 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/BlockStartState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// The block that begins a closure loop.
+  class ANTLR4CPP_PUBLIC StarBlockStartState final : public BlockStartState {
+
+  public:
+    virtual size_t getStateType() override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/StarLoopEntryState.h

@@ -0,0 +1,35 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC StarLoopEntryState final : public DecisionState {
+  public:
+    StarLoopEntryState();
+
+    /**
+     * Indicates whether this state can benefit from a precedence DFA during SLL
+     * decision making.
+     *
+     * <p>This is a computed property that is calculated during ATN deserialization
+     * and stored for use in {@link ParserATNSimulator} and
+     * {@link ParserInterpreter}.</p>
+     *
+     * @see DFA#isPrecedenceDfa()
+     */
+    bool isPrecedenceDecision = false;
+
+    StarLoopbackState *loopBackState = nullptr;
+
+    virtual size_t getStateType() override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/StarLoopbackState.h

@@ -0,0 +1,21 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/ATNState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC StarLoopbackState final : public ATNState {
+  public:
+    StarLoopEntryState *getLoopEntryState();
+
+    virtual size_t getStateType() override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/TokensStartState.h

@@ -0,0 +1,21 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/DecisionState.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// The Tokens rule start state linking to each lexer rule start state.
+  class ANTLR4CPP_PUBLIC TokensStartState final : public DecisionState {
+
+  public:
+    virtual size_t getStateType() override;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/Transition.h

@@ -0,0 +1,76 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "misc/IntervalSet.h"
+
+namespace antlr4 {
+namespace atn {
+
+  /// <summary>
+  /// An ATN transition between any two ATN states.  Subclasses define
+  ///  atom, set, epsilon, action, predicate, rule transitions.
+  /// <p/>
+  ///  This is a one way link.  It emanates from a state (usually via a list of
+  ///  transitions) and has a target state.
+  /// <p/>
+  ///  Since we never have to change the ATN transitions once we construct it,
+  ///  we can fix these transitions as specific classes. The DFA transitions
+  ///  on the other hand need to update the labels as it adds transitions to
+  ///  the states. We'll use the term Edge for the DFA to distinguish them from
+  ///  ATN transitions.
+  /// </summary>
+  class ANTLR4CPP_PUBLIC Transition {
+  public:
+    // constants for serialization
+    enum SerializationType {
+      EPSILON = 1,
+      RANGE = 2,
+      RULE = 3,
+      PREDICATE = 4, // e.g., {isType(input.LT(1))}?
+      ATOM = 5,
+      ACTION = 6,
+      SET = 7, // ~(A|B) or ~atom, wildcard, which convert to next 2
+      NOT_SET = 8,
+      WILDCARD = 9,
+      PRECEDENCE = 10,
+    };
+
+    static const std::vector<std::string> serializationNames;
+
+    /// The target of this transition.
+    // ml: this is a reference into the ATN.
+    ATNState *target;
+
+    virtual ~Transition();
+
+  protected:
+    Transition(ATNState *target);
+
+  public:
+    virtual SerializationType getSerializationType() const = 0;
+
+    /**
+     * Determines if the transition is an "epsilon" transition.
+     *
+     * <p>The default implementation returns {@code false}.</p>
+     *
+     * @return {@code true} if traversing this transition in the ATN does not
+     * consume an input symbol; otherwise, {@code false} if traversing this
+     * transition consumes (matches) an input symbol.
+     */
+    virtual bool isEpsilon() const;
+    virtual misc::IntervalSet label() const;
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const = 0;
+
+    virtual std::string toString() const;
+
+    Transition(Transition const&) = delete;
+    Transition& operator=(Transition const&) = delete;
+  };
+
+} // namespace atn
+} // namespace antlr4

lib/antlr4/include/atn/WildcardTransition.h

@@ -0,0 +1,25 @@
+/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+#pragma once
+
+#include "atn/Transition.h"
+
+namespace antlr4 {
+namespace atn {
+
+  class ANTLR4CPP_PUBLIC WildcardTransition final : public Transition {
+  public:
+    WildcardTransition(ATNState *target);
+
+    virtual SerializationType getSerializationType() const override;
+
+    virtual bool matches(size_t symbol, size_t minVocabSymbol, size_t maxVocabSymbol) const override;
+
+    virtual std::string toString() const override;
+  };
+
+} // namespace atn
+} // namespace antlr4