/\\\\\\(?=[$.|*+(){^])/g,
        () => ESCAPE
    ],

    [
        // '\\\\' -> '\\'
        /\\\\/g,
        () => ESCAPE
    ],

    [
        // > The range notation, e.g. [a-zA-Z],
        // > can be used to match one of the characters in a range.

        // `\` is escaped by step 3
        /(\\)?\[([^\]/]*?)(\\*)($|\])/g,