antlr4-runtime/src/antlr4/action/LexerCustomAction.js

JavaScript runtime for ANTLR4

/* Copyright (c) 2012-2022 The ANTLR Project Contributors. All rights reserved.
 * Use is of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */
import {default as LexerActionType } from "../atn/LexerActionType.js";
import LexerAction from "./LexerAction.js";

/**
 * Executes a custom lexer action by calling {@link Recognizer//action} with the
 * rule and action indexes assigned to the custom action. The implementation of
 * a custom action is added to the generated code for the lexer in an override
 * of {@link Recognizer//action} when the grammar is compiled.
 *
 * <p>This class may represent embedded actions created with the <code>{...}</code>
 * syntax in ANTLR 4, as well as actions created for lexer commands where the
 * command argument could not be evaluated when the grammar was compiled.</p>
 */
export default class LexerCustomAction extends LexerAction {
    /**
     * Constructs a custom lexer action with the specified rule and action
     * indexes.
     *
     * @param ruleIndex The rule index to use for calls to
     * {@link Recognizer//action}.
     * @param actionIndex The action index to use for calls to
     * {@link Recognizer//action}.
     */
    constructor(ruleIndex, actionIndex) {
        super(LexerActionType.CUSTOM);
        this.ruleIndex = ruleIndex;
        this.actionIndex = actionIndex;
        this.isPositionDependent = true;
    }

    /**
     * <p>Custom actions are implemented by calling {@link Lexer//action} with the
     * appropriate rule and action indexes.</p>
     */
    execute(lexer) {
        lexer.action(null, this.ruleIndex, this.actionIndex);
    }

    updateHashCode(hash) {
        hash.update(this.actionType, this.ruleIndex, this.actionIndex);
    }

    equals(other) {
        if (this === other) {
            return true;
        } else if (! (other instanceof LexerCustomAction)) {
            return false;
        } else {
            return this.ruleIndex === other.ruleIndex && this.actionIndex === other.actionIndex;
        }
    }
}