/*!
 * 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.
     *
     * @return 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.
     *
     * <p>Many lexer commands, including {@code type}, {@code skip}, and
     * {@code 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`.</p>
     *
     * @return {@code true} if the lexer action semantics can be affected by the
     * position of the input {@link CharStream} at the time it is executed;
     * otherwise, {@code false}.
     */
    readonly isPositionDependent: boolean;
    /**
     * Execute the lexer action in the context of the specified {@link Lexer}.
     *
     * <p>For position-dependent actions, the input stream must already be
     * positioned correctly prior to calling this method.</p>
     *
     * @param lexer The lexer instance.
     */
    execute(lexer: Lexer): void;
}