/*! * Copyright 2016 The ANTLR Project. All rights reserved. * Licensed under the BSD-3-Clause license. See LICENSE file in the project root for license information. */ import { ANTLRErrorListener } from './ANTLRErrorListener'; import { ATNConfigSet } from './atn/ATNConfigSet'; import { BitSet } from './misc/BitSet'; import { DFA } from './dfa/DFA'; import { Parser } from './Parser'; import { SimulatorState } from './atn/SimulatorState'; import { Token } from './Token'; /** How to emit recognition errors for parsers. */ export interface ParserErrorListener extends ANTLRErrorListener { /** * This method is called by the parser when a full-context prediction * results in an ambiguity. * *

Each full-context prediction which does not result in a syntax error * will call either {@link #reportContextSensitivity} or * {@link #reportAmbiguity}.

* *

* When {@code ambigAlts} is not null, it contains the set of potentially * viable alternatives identified by the prediction algorithm. When * {@code ambigAlts} is null, use * {@link ATNConfigSet#getRepresentedAlternatives} to obtain the represented * alternatives from the {@code configs} argument.

* *

When {@code exact} is {@code true}, all of the potentially * viable alternatives are truly viable, i.e. this is reporting an exact * ambiguity. When {@code exact} is {@code false}, at least two of * the potentially viable alternatives are viable for the current input, but * the prediction algorithm terminated as soon as it determined that at * least the minimum potentially viable alternative is truly * viable.

* *

When the {@link PredictionMode#LL_EXACT_AMBIG_DETECTION} prediction * mode is used, the parser is required to identify exact ambiguities so * {@code exact} will always be {@code true}.

* * @param recognizer the parser instance * @param dfa the DFA for the current decision * @param startIndex the input index where the decision started * @param stopIndex the input input where the ambiguity was identified * @param exact {@code true} if the ambiguity is exactly known, otherwise * {@code false}. This is always {@code true} when * {@link PredictionMode#LL_EXACT_AMBIG_DETECTION} is used. * @param ambigAlts the potentially ambiguous alternatives, or {@code null} * to indicate that the potentially ambiguous alternatives are the complete * set of represented alternatives in {@code configs} * @param configs the ATN configuration set where the ambiguity was * identified */ reportAmbiguity?: (recognizer: Parser, dfa: DFA, startIndex: number, stopIndex: number, exact: boolean, ambigAlts: BitSet | undefined, configs: ATNConfigSet) => void; /** * This method is called when an SLL conflict occurs and the parser is about * to use the full context information to make an LL decision. * *

If one or more configurations in {@code configs} contains a semantic * predicate, the predicates are evaluated before this method is called. The * subset of alternatives which are still viable after predicates are * evaluated is reported in {@code conflictingAlts}.

* * @param recognizer the parser instance * @param dfa the DFA for the current decision * @param startIndex the input index where the decision started * @param stopIndex the input index where the SLL conflict occurred * @param conflictingAlts The specific conflicting alternatives. If this is * {@code null}, the conflicting alternatives are all alternatives * represented in {@code configs}. * @param conflictState the simulator state when the SLL conflict was * detected */ reportAttemptingFullContext?: (recognizer: Parser, dfa: DFA, startIndex: number, stopIndex: number, conflictingAlts: BitSet | undefined, conflictState: SimulatorState) => void; /** * This method is called by the parser when a full-context prediction has a * unique result. * *

Each full-context prediction which does not result in a syntax error * will call either {@link #reportContextSensitivity} or * {@link #reportAmbiguity}.

* *

For prediction implementations that only evaluate full-context * predictions when an SLL conflict is found (including the default * {@link ParserATNSimulator} implementation), this method reports cases * where SLL conflicts were resolved to unique full-context predictions, * i.e. the decision was context-sensitive. This report does not necessarily * indicate a problem, and it may appear even in completely unambiguous * grammars.

* *

{@code configs} may have more than one represented alternative if the * full-context prediction algorithm does not evaluate predicates before * beginning the full-context prediction. In all cases, the final prediction * is passed as the {@code prediction} argument.

* *

Note that the definition of "context sensitivity" in this method * differs from the concept in {@link DecisionInfo#contextSensitivities}. * This method reports all instances where an SLL conflict occurred but LL * parsing produced a unique result, whether or not that unique result * matches the minimum alternative in the SLL conflicting set.

* * @param recognizer the parser instance * @param dfa the DFA for the current decision * @param startIndex the input index where the decision started * @param stopIndex the input index where the context sensitivity was * finally determined * @param prediction the unambiguous result of the full-context prediction * @param acceptState the simulator state when the unambiguous prediction * was determined */ reportContextSensitivity?: (recognizer: Parser, dfa: DFA, startIndex: number, stopIndex: number, prediction: number, acceptState: SimulatorState) => void; }