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Kotlin multiplatform port of ANTLR

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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.
 */

package org.antlr.v4.kotlinruntime

import org.antlr.v4.kotlinruntime.misc.ParseCancellationException

/**
 * This implementation of [ANTLRErrorStrategy] responds to syntax errors
 * by immediately canceling the parse operation with a
 * [ParseCancellationException]. The implementation ensures that the
 * [ParserRuleContext.exception] field is set for all parse tree nodes
 * that were not completed prior to encountering the error.
 *
 *
 *
 * This error strategy is useful in the following scenarios.
 *
 *
 *  * **Two-stage parsing:** 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 [BailErrorStrategy.sync] improves the performance of
 * the first stage.
 *  * **Silent validation:** When syntax errors are not being
 * reported or logged, and the parse result is simply ignored if errors occur,
 * the [BailErrorStrategy] avoids wasting work on recovering from errors
 * when the result will be ignored either way.
 *
 *
 *
 *
 * `myparser.setErrorHandler(new BailErrorStrategy());`
 *
 * @see Parser.setErrorHandler
 */
class BailErrorStrategy : DefaultErrorStrategy() {
    /** Instead of recovering from exception `e`, re-throw it wrapped
     * in a [ParseCancellationException] so it is not caught by the
     * rule function catches.  Use [Exception.getCause] to get the
     * original [RecognitionException].
     */
    override fun recover(recognizer: Parser, e: RecognitionException) {
        var context = recognizer.context
        while (context != null) {
            context!!.exception = e
            context = context!!.readParent() as ParserRuleContext?
        }

        throw ParseCancellationException(e)
    }

    /** Make sure we don't attempt to recover inline; if the parser
     * successfully recovers, it won't throw an exception.
     */
    override fun recoverInline(recognizer: Parser): Token {
        val e = InputMismatchException(recognizer)
        var context = recognizer.context
        while (context != null) {
            context!!.exception = e
            context = context!!.readParent() as ParserRuleContext?
        }

        throw ParseCancellationException(e)
    }

    /** Make sure we don't attempt to recover from problems in subrules.  */
    override fun sync(recognizer: Parser) {}
}