/*! * 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 { Parser } from "./Parser"; import { Token } from "./Token"; import { RecognitionException } from "./RecognitionException"; /** * The interface for defining strategies to deal with syntax errors encountered * during a parse by ANTLR-generated parsers. We distinguish between three * different kinds of errors: * * * The parser could not figure out which path to take in the ATN (none of * the available alternatives could possibly match) * * The current input does not match what we were looking for * * A predicate evaluated to false * * Implementations of this interface report syntax errors by calling * {@link Parser#notifyErrorListeners}. * * TODO: what to do about lexers */ export interface ANTLRErrorStrategy { /** * Reset the error handler state for the specified `recognizer`. * @param recognizer the parser instance */ reset(/*@NotNull*/ recognizer: Parser): void; /** * This method is called when an unexpected symbol is encountered during an * inline match operation, such as {@link Parser#match}. If the error * strategy successfully recovers from the match failure, this method * returns the {@link Token} instance which should be treated as the * successful result of the match. * * This method handles the consumption of any tokens - the caller should * *not* call {@link Parser#consume} after a successful recovery. * * Note that the calling code will not report an error if this method * returns successfully. The error strategy implementation is responsible * for calling {@link Parser#notifyErrorListeners} as appropriate. * * @param recognizer the parser instance * @ if the error strategy was not able to * recover from the unexpected input symbol */ recoverInline(/*@NotNull*/ recognizer: Parser): Token; /** * This method is called to recover from exception `e`. This method is * called after {@link #reportError} by the default exception handler * generated for a rule method. * * @see #reportError * * @param recognizer the parser instance * @param e the recognition exception to recover from * @ if the error strategy could not recover from * the recognition exception */ recover(/*@NotNull*/ recognizer: Parser, /*@NotNull*/ e: RecognitionException): void; /** * This method provides the error handler with an opportunity to handle * syntactic or semantic errors in the input stream before they result in a * {@link RecognitionException}. * * The generated code currently contains calls to {@link #sync} after * entering the decision state of a closure block (`(...)*` or * `(...)+`). * * For an implementation based on Jim Idle's "magic sync" mechanism, see * {@link DefaultErrorStrategy#sync}. * * @see DefaultErrorStrategy#sync * * @param recognizer the parser instance * @ if an error is detected by the error * strategy but cannot be automatically recovered at the current state in * the parsing process */ sync(/*@NotNull*/ recognizer: Parser): void; /** * Tests whether or not `recognizer` is in the process of recovering * from an error. In error recovery mode, {@link Parser#consume} adds * symbols to the parse tree by calling * {@link Parser#createErrorNode(ParserRuleContext, Token)} then * {@link ParserRuleContext#addErrorNode(ErrorNode)} instead of * {@link Parser#createTerminalNode(ParserRuleContext, Token)}. * * @param recognizer the parser instance * @returns `true` if the parser is currently recovering from a parse * error, otherwise `false` */ inErrorRecoveryMode(/*@NotNull*/ recognizer: Parser): boolean; /** * This method is called by when the parser successfully matches an input * symbol. * * @param recognizer the parser instance */ reportMatch(/*@NotNull*/ recognizer: Parser): void; /** * Report any kind of {@link RecognitionException}. This method is called by * the default exception handler generated for a rule method. * * @param recognizer the parser instance * @param e the recognition exception to report */ reportError(recognizer: Parser, e: RecognitionException): void; }