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[toc] / antlr4-cpp-runtime-4.9.2-source / runtime / src / DiagnosticErrorListener.h

diff --git a/antlr4-cpp-runtime-4.9.2-source/runtime/src/DiagnosticErrorListener.h b/antlr4-cpp-runtime-4.9.2-source/runtime/src/DiagnosticErrorListener.h
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+/* 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 "BaseErrorListener.h"
+
+namespace antlr4 {
+
+  /// <summary>
+  /// This implementation of <seealso cref="ANTLRErrorListener"/> can be used to identify
+  /// certain potential correctness and performance problems in grammars. "Reports"
+  /// are made by calling <seealso cref="Parser#notifyErrorListeners"/> with the appropriate
+  /// message.
+  ///
+  /// <ul>
+  /// <li><b>Ambiguities</b>: These are cases where more than one path through the
+  /// grammar can match the input.</li>
+  /// <li><b>Weak context sensitivity</b>: These are cases where full-context
+  /// prediction resolved an SLL conflict to a unique alternative which equaled the
+  /// minimum alternative of the SLL conflict.</li>
+  /// <li><b>Strong (forced) context sensitivity</b>: These are cases where the
+  /// full-context prediction resolved an SLL conflict to a unique alternative,
+  /// <em>and</em> the minimum alternative of the SLL conflict was found to not be
+  /// a truly viable alternative. Two-stage parsing cannot be used for inputs where
+  /// this situation occurs.</li>
+  /// </ul>
+  ///
+  /// @author Sam Harwell
+  /// </summary>
+  class ANTLR4CPP_PUBLIC DiagnosticErrorListener : public BaseErrorListener {
+    /// <summary>
+    /// When {@code true}, only exactly known ambiguities are reported.
+    /// </summary>
+  protected:
+    const bool exactOnly;
+
+    /// <summary>
+    /// Initializes a new instance of <seealso cref="DiagnosticErrorListener"/> which only
+    /// reports exact ambiguities.
+    /// </summary>
+  public:
+    DiagnosticErrorListener();
+
+    /// <summary>
+    /// Initializes a new instance of <seealso cref="DiagnosticErrorListener"/>, specifying
+    /// whether all ambiguities or only exact ambiguities are reported.
+    /// </summary>
+    /// <param name="exactOnly"> {@code true} to report only exact ambiguities, otherwise
+    /// {@code false} to report all ambiguities. </param>
+    DiagnosticErrorListener(bool exactOnly);
+
+    virtual void reportAmbiguity(Parser *recognizer, const dfa::DFA &dfa, size_t startIndex, size_t stopIndex, bool exact,
+      const antlrcpp::BitSet &ambigAlts, atn::ATNConfigSet *configs) override;
+
+    virtual void reportAttemptingFullContext(Parser *recognizer, const dfa::DFA &dfa, size_t startIndex, size_t stopIndex,
+      const antlrcpp::BitSet &conflictingAlts, atn::ATNConfigSet *configs) override;
+
+    virtual void reportContextSensitivity(Parser *recognizer, const dfa::DFA &dfa, size_t startIndex, size_t stopIndex,
+      size_t prediction, atn::ATNConfigSet *configs) override;
+
+  protected:
+    virtual std::string getDecisionDescription(Parser *recognizer, const dfa::DFA &dfa);
+
+    /// <summary>
+    /// Computes the set of conflicting or ambiguous alternatives from a
+    /// configuration set, if that information was not already provided by the
+    /// parser.
+    /// </summary>
+    /// <param name="reportedAlts"> The set of conflicting or ambiguous alternatives, as
+    /// reported by the parser. </param>
+    /// <param name="configs"> The conflicting or ambiguous configuration set. </param>
+    /// <returns> Returns {@code reportedAlts} if it is not {@code null}, otherwise
+    /// returns the set of alternatives represented in {@code configs}. </returns>
+    virtual antlrcpp::BitSet getConflictingAlts(const antlrcpp::BitSet &reportedAlts, atn::ATNConfigSet *configs);
+  };
+
+} // namespace antlr4