定义2个变量并打印

定义2个变量并打印

我刚刚开始使用 LaTeX,但是一些最基础的东西还在苦苦挣扎。

我创建了 2 个命令,每个命令为一个变量分配一个值:

\newcommand{\firstname}[1]{\def\@firstname{#1}}
\newcommand{\lastname}[1]{\def\@lastname{#1}}

这些变量是使用文档开头某处的命令设置的:

\firstname{Kevin}
\lastname{De Coninck}

当我尝试打印 时lastname,一切正常,当我尝试打印 时firstname,返回以下错误。Use of \@ doesn't match its definition. \@f

我正在使用以下代码在文档中进行打印:

\begin{document}
    \@firstname
\end{document}

我在这里遗漏了什么?

更新:整个文档

% ----------------------------------------------------------------------
% -- CONFIGURATION
% ----------------------------------------------------------------------
\documentclass[11pt, a4paper]{article}

% ----------------------------------------------------------------------
% -- PACKAGES
% ----------------------------------------------------------------------
\RequirePackage{geometry}

% ----------------------------------------------------------------------
% -- COMMAND DEFINITIONS
% ----------------------------------------------------------------------

% Summary: Configure the person's name.
% Usage:   \name{<firstname>}{<lastname>}
%          firstname{<firstname>}
%          lastname{<lastname>}
\newcommand{\firstname}[1]{\def\@firstname{#1}}
\newcommand{\lastname}[1]{\def\@lastname{#1}}

% ----------------------------------------------------------------------
% -- LAYOUT CONFIGURATION
% ----------------------------------------------------------------------
\geometry{left=2.0cm, top=5.5cm, right=2.0cm, bottom=2.0cm, footskip=.5cm}

% ----------------------------------------------------------------------
% -- PERSONAL DATA
% ----------------------------------------------------------------------
\firstname{Kevin}
\lastname{De Coninck}

% ----------------------------------------------------------------------
% -- ACTUAL DOCUMENT
% ----------------------------------------------------------------------
\begin{document}
    \@firstname
    \@lastname
\end{document}

答案1

\makeatletter...\makeatother我在定义和用法周围添加了常见的对。

请也记住 daleif 的提议:\CMPLXfirstname似乎更好、更容易。

我也改成\RequirePackage\usepackage(虽然第一个也是允许的,但只适用于包裹,不适用于普通文档)

现在,@是作为内部命令名称的一部分保留的特殊字符,普通文档用户不应轻易访问这些字符。包或类文件之外的字符@不被视为命令名称的允许字母,因此\makeatletter(暂时)更改了此设置,允许@将其作为此类名称的一部分,然后\makeatother恢复此设置。

% ----------------------------------------------------------------------
% -- CONFIGURATION
% ----------------------------------------------------------------------
\documentclass[11pt, a4paper]{article}

% ----------------------------------------------------------------------
% -- PACKAGES
% ----------------------------------------------------------------------
\usepackage{geometry}

% ----------------------------------------------------------------------
% -- COMMAND DEFINITIONS
% ----------------------------------------------------------------------

% Summary: Configure the person's name.
% Usage:   \name{<firstname>}{<lastname>}
%          firstname{<firstname>}
%          lastname{<lastname>}
\makeatletter
\newcommand{\firstname}[1]{\def\@firstname{#1}}
\newcommand{\lastname}[1]{\def\@lastname{#1}}

 \newcommand{\printname}{%
  \@ifundefined{@firstname}{}{\@firstname} \@ifundefined{@lastname}{}{\@lastname}%
}

\makeatother

% ----------------------------------------------------------------------
% -- LAYOUT CONFIGURATION
% ----------------------------------------------------------------------
\geometry{left=2.0cm, top=5.5cm, right=2.0cm, bottom=2.0cm, footskip=.5cm}

% ----------------------------------------------------------------------
% -- PERSONAL DATA
% ----------------------------------------------------------------------
\firstname{Kevin}
\lastname{De Coninck}

% ----------------------------------------------------------------------
% -- ACTUAL DOCUMENT
% ----------------------------------------------------------------------
\begin{document}
\makeatletter
    \@firstname\ \@lastname
\makeatother

Or \printname%
\end{document}

在此处输入图片描述

答案2

如果您不想使用\makeatletter.. \makeatother,您可以使用
\csname..\endcsname

\csname @firstname\endcsname →  \@firstname
\csname @lastname\endcsname →  \@lastname

我写了一个小包装器\csname..\endcsname

该宏的\CreateCsFromName工作原理如下:

\CreateCsFromName<preceding tokens with no curly braces>{ControlSequence}
→  <preceding tokens with no curly braces>\ControlSequence

如果省略<preceding tokens with no curly braces>,即如果留空<preceding tokens with no curly braces>,则\CreateCsFromName只会从控制序列的名称构造控制序列标记:

\CreateCsFromName{macro}→ \macro

<preceding tokens with no curly braces>您可以提供任何命令来(重新)定义,而不必留空:

\CreateCsFromName\long\def{macro}→ \long\def\macro

\CreateCsFromName\long\def{macro}#1#2{First argument: #1, second argument: #2}
→ \long\def\macro#1#2{First argument: #1, second argument: #2}

\CreateCsFromName\newcommand*{macro}→ \newcommand*\macro

\CreateCsFromName\newcommand*{macro}[2]{First argument: #1, second argument: #2}
→ \newcommand*\macro[2]{First argument: #1, second argument: #2}

例子:

\documentclass{article}

\newcommand\Exchange[2]{#2#1}
\newcommand\CreateCsFromName{}
\long\def\CreateCsFromName#1#{\romannumeral0\InnerCreateCsFromName{#1}}
\newcommand\InnerCreateCsFromName[2]{%
  \expandafter\Exchange\expandafter{\csname#2\endcsname}{ #1}%
}

% raise an error in case \@firstname and \@lastname are already defined:
\CreateCsFromName\newcommand*{@firstname}{}
\CreateCsFromName\newcommand*{@lastname}{}

% commands for silently redefining \@firstname and \@lastname:
\newcommand{\firstname}{\CreateCsFromName\def{@firstname}}
\newcommand{\lastname}{\CreateCsFromName\def{@lastname}}

\firstname{Kevin}
\lastname{De Coninck}

\begin{document}

\CreateCsFromName{@firstname} \CreateCsFromName{@lastname}

\end{document}

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