commonMain.org.antlr.v4.kotlinruntime.atn.AmbiguityInfo.kt Maven / Gradle / Ivy
// Copyright 2017-present Strumenta and contributors, licensed under Apache 2.0.
// Copyright 2024-present Strumenta and contributors, licensed under BSD 3-Clause.
package org.antlr.v4.kotlinruntime.atn
import com.strumenta.antlrkotlin.runtime.BitSet
import org.antlr.v4.kotlinruntime.ANTLRErrorListener
import org.antlr.v4.kotlinruntime.TokenStream
/**
* 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.
* [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 [PredictionMode.SLL], which in turn means
* they cannot use the two-stage parsing strategy to improve parsing performance
* for that input.
*
* @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 `true` if the ambiguity was identified during LL prediction,
* otherwise `false` if the ambiguity was identified during SLL prediction
*
* @see ParserATNSimulator.reportAmbiguity
* @see ANTLRErrorListener.reportAmbiguity
*
* @since 4.3
*/
@Suppress("MemberVisibilityCanBePrivate")
public class AmbiguityInfo(
decision: Int,
configs: ATNConfigSet?,
public var ambigAlts: BitSet,
input: TokenStream,
startIndex: Int,
stopIndex: Int,
fullCtx: Boolean,
) : DecisionEventInfo(decision, configs, input, startIndex, stopIndex, fullCtx)