antlr4ts/atn/LexerAction.d.ts

ANTLR 4 runtime for JavaScript written in Typescript

/*!
 * 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 { Equatable } from "../misc/Stubs";
import { Lexer } from "../Lexer";
import { LexerActionType } from "./LexerActionType";
/**
 * Represents a single action which can be executed following the successful
 * match of a lexer rule. Lexer actions are used for both embedded action syntax
 * and ANTLR 4's new lexer command syntax.
 *
 * @author Sam Harwell
 * @since 4.2
 */
export interface LexerAction extends Equatable {
    /**
     * Gets the serialization type of the lexer action.
     *
     * @returns The serialization type of the lexer action.
     */
    readonly actionType: LexerActionType;
    /**
     * Gets whether the lexer action is position-dependent. Position-dependent
     * actions may have different semantics depending on the {@link CharStream}
     * index at the time the action is executed.
     *
     * Many lexer commands, including `type`, `skip`, and
     * `more`, do not check the input index during their execution.
     * Actions like this are position-independent, and may be stored more
     * efficiently as part of the `ATNConfig.lexerActionExecutor`.
     *
     * @returns `true` if the lexer action semantics can be affected by the
     * position of the input {@link CharStream} at the time it is executed;
     * otherwise, `false`.
     */
    readonly isPositionDependent: boolean;
    /**
     * Execute the lexer action in the context of the specified {@link Lexer}.
     *
     * For position-dependent actions, the input stream must already be
     * positioned correctly prior to calling this method.
     *
     * @param lexer The lexer instance.
     */
    execute(/*@NotNull*/ lexer: Lexer): void;
}