cpp/third_party/antlr4-cpp-runtime-4/runtime/src/BailErrorStrategy.h

/* 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 "DefaultErrorStrategy.h"

namespace antlr4 {

  /**
   * This implementation of {@link ANTLRErrorStrategy} responds to syntax errors
   * by immediately canceling the parse operation with a
   * {@link ParseCancellationException}. The implementation ensures that the
   * {@link ParserRuleContext#exception} field is set for all parse tree nodes
   * that were not completed prior to encountering the error.
   *
   * <p>
   * This error strategy is useful in the following scenarios.</p>
   *
   * <ul>
   * <li><strong>Two-stage parsing:</strong> This error strategy allows the first
   * stage of two-stage parsing to immediately terminate if an error is
   * encountered, and immediately fall back to the second stage. In addition to
   * avoiding wasted work by attempting to recover from errors here, the empty
   * implementation of {@link BailErrorStrategy#sync} improves the performance of
   * the first stage.</li>
   * <li><strong>Silent validation:</strong> When syntax errors are not being
   * reported or logged, and the parse result is simply ignored if errors occur,
   * the {@link BailErrorStrategy} avoids wasting work on recovering from errors
   * when the result will be ignored either way.</li>
   * </ul>
   *
   * <p>
   * {@code myparser.setErrorHandler(new BailErrorStrategy());}</p>
   *
   * @see Parser#setErrorHandler(ANTLRErrorStrategy)
   */
  class ANTLR4CPP_PUBLIC BailErrorStrategy : public DefaultErrorStrategy {
    /// <summary>
    /// Instead of recovering from exception {@code e}, re-throw it wrapped
    ///  in a <seealso cref="ParseCancellationException"/> so it is not caught by the
    ///  rule function catches.  Use <seealso cref="Exception#getCause()"/> to get the
    ///  original <seealso cref="RecognitionException"/>.
    /// </summary>
  public:
    virtual void recover(Parser *recognizer, std::exception_ptr e) override;

    /// Make sure we don't attempt to recover inline; if the parser
    ///  successfully recovers, it won't throw an exception.
    virtual Token* recoverInline(Parser *recognizer) override;

    /// <summary>
    /// Make sure we don't attempt to recover from problems in subrules. </summary>
    virtual void sync(Parser *recognizer) override;
  };

} // namespace antlr4