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Statistical sampling library for use in virtdata libraries, based on apache commons math 4

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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.runtime.atn;

import org.antlr.v4.runtime.ANTLRErrorListener;
import org.antlr.v4.runtime.TokenStream;

import java.util.BitSet;

/**
 * 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).
 *
 * 

* 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. * {@link 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.

* *

* 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 {@link PredictionMode#SLL}, which in turn means * they cannot use the two-stage parsing strategy to improve parsing performance * for that input.

* * @see ParserATNSimulator#reportAmbiguity * @see ANTLRErrorListener#reportAmbiguity * * @since 4.3 */ public class AmbiguityInfo extends DecisionEventInfo { /** The set of alternative numbers for this decision event that lead to a valid parse. */ public BitSet ambigAlts; /** * Constructs a new instance of the {@link AmbiguityInfo} class with the * specified detailed ambiguity information. * * @param decision The decision number * @param configs The final configuration set identifying the ambiguous * alternatives for the current input * @param ambigAlts The set of alternatives in the decision that lead to a valid parse. * The predicted alt is the min(ambigAlts) * @param input The input token stream * @param startIndex The start index for the current prediction * @param stopIndex The index at which the ambiguity was identified during * prediction * @param fullCtx {@code true} if the ambiguity was identified during LL * prediction; otherwise, {@code false} if the ambiguity was identified * during SLL prediction */ public AmbiguityInfo(int decision, ATNConfigSet configs, BitSet ambigAlts, TokenStream input, int startIndex, int stopIndex, boolean fullCtx) { super(decision, configs, input, startIndex, stopIndex, fullCtx); this.ambigAlts = ambigAlts; } }




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