在自定义类中使用变量

Question

我正在为我的教职员工开发一个自定义文档类。创建首页时，我想添加一些自定义变量。例如标题、作者、主管等。我可以在单个文档中完成这些操作，但在创建自定义类时却无法完成。

这是我的自定义类代码：

\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{iseg-general}[General template for written work at ISEG]


\LoadClass [12pt,a4paper,oneside]{article}

% Set font type to 'Times New Roman'.
\usepackage{times}

% Portuguese accents just in case.
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

\usepackage[style=authoryear,backend=biber]{biblatex}

\addbibresource{bibliography.bib}% Syntax for version >= 1.2

% English language.
\usepackage[english]{babel}

% appendix
\usepackage[titletoc,toc,title]{appendix}
\newcommand{\nocontentsline}[3]{}
\newcommand{\tocless}[2]{\bgroup\let\addcontentsline=\nocontentsline#1{#2}\egroup}

\makeatletter

\def\@biblabel#1{\hspace*{-\labelsep}}

\makeatother

% Set margins to 3cm.
\usepackage[top=3cm, bottom=3cm, left=3cm, right=3cm]{geometry}

% Change margins command.
\def\changemargin#1#2{\list{}{\rightmargin#2\leftmargin#1}\item[]}
\let\endchangemargin=\endlist

% Paragraph indentation.
\usepackage{indentfirst}

% Set vertical spacing to 1.5 lines.
\usepackage{setspace}
\onehalfspacing

\makeatletter
% Page headers and footers customisation.
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{}
    % Set left header to footnotesize (10pt) and upper cases.
\lhead{\textsf{\scriptsize \textsc{\@author}}}
    % Set left header to footnotesize (10pt) and upper cases.
\rhead{\textsf{\scriptsize \textsc{\@title}}}
    % Set centred footer to page number.
\cfoot{\thepage}
\makeatother


% Customise chapters, sections, subsections, and subsubsections.
\usepackage{titlesec}
    % Set chapters' titles to upper cases and centred.
\titleformat{\chapter}[display]
  {\scshape\center}
  {}
  {0pt}
  {\thechapter.\ }
  \usepackage{etoolbox}% Stop chapters from starting at new page.
\makeatletter
\patchcmd{\chapter}{\if@openright\cleardoublepage\else\clearpage\fi}{}{}{}
\makeatother
    % Set sections' titles to upper cases and centred.
\titleformat{\section}
  {\scshape\center}{\thesection}{1em}{}
    % Set subsections' titles to italic and centred.
\titleformat{\subsection}
  {\itshape\center}{\thesubsection}{1em}{}
    % Idem for subsubsections' titles.
\titleformat{\subsubsection}
  {\itshape\center}{\thesubsection}{1em}{}


% Link objects (e.g. tables, figures, pages) in the body of text.
\usepackage{hyperref}

% Build a glossary.
%\usepackage{glossaries}
%\makeglossaries
  % Define, e.g. acronyms (\newacronym{<label>}{<abbrv>}{<full>}).
  % Use \gls{<label>} command to call the acronym in the text. On first use the \gls command will display "<full> (<abbrv>)". On subsequent uses only the abbreviation will be displayed.



% Customize table of contents.
\usepackage{tocloft}
\setlength{\cftbeforetoctitleskip}{0pt}
%   \addto\captionsenglish{%
%   \renewcommand{\contentsname}{\hfill\normalfont\scshape\normalsize Table of Contents\hfill}
    %\renewcommand{\cftaftertoctitle}{\hfill}
%   }

%\addto\captionsenglish{%
 % \renewcommand{\contentsname}%
  %  {\scshape Table of Contents}%
%}
\setlength{\cftbeforeloftitleskip}{0pt}
\setlength{\cftbeforelottitleskip}{0pt}

%Customise tables.
\renewcommand*\thetable{\Roman{table}}% Roman Numerals Tables
\addto\captionsenglish{\renewcommand{\tablename}{\textsc{Table}}}% Full Caps Tables
\addto\captionsenglish{\renewcommand{\figurename}{\textsc{Figure}}}% Full Caps Figures

%%%%%%%%%%%Tables

\usepackage{booktabs}
\usepackage{adjustbox}
\setlength\heavyrulewidth{0.3ex}

\usepackage{tabularx}
\usepackage{array}

\usepackage{threeparttable}


%Quotes
\usepackage{csquotes}



\renewcommand*{\maketitle}{%
\begin{titlepage}
  \pagestyle{empty}
     \centering
     \begin{flushleft}
          \includegraphics[width=0.3\linewidth]{graphics/Logotipo_ISEG.png}
     \end{flushleft}


     \vspace{3cm}
        {\textsf{\Large Macroeconomics}} \\ [1cm]
         {\textsf{\Large 2018/2020}} \\ [3cm]
       {\textsf{\Large \@title }} \\ [2cm] % <- delete the  irrelevant parts
     \begin{flushleft}
     {\uppercase{\Large \@title }} \\ [1.5cm] % <- write here the title of your thesis
     {\uppercase{\Large \@author }}  \\ [2cm]% <- write here the title of your thesis
     \end{flushleft}
     \textsf{
     \underline{Author:} \\
     \@author}
         \vfill
     %Date
         {\textsf{\Large ISEG, 29th  December 2018}}  % <- write here the date
      \clearpage
\end{titlepage}

}

在 \begin{titlepage} 范围内，我希望能够打印我的自定义变量，并使其中一些具有条件，例如，如果未定义某些变量，TeX 不应抛出任何错误。