如何暂时删除定义环境中的格式？

Question

我有一个定义，写如下：

\begin{definition}
This is a definition, in which I would like to have a few normal words.
\end{definition}

通常，整个定义都以斜体。但我想删除“正常”格式，使其看起来没有斜体。有没有什么快捷的方法可以实现这个目的？

Answer 1

您可以使用 手动更改字体形状\upshape。或者，您可以重新定义\itshape（切换到斜体字体）意味着将其默认为\upshape。后者可以使用 [etoolbox软件包 ][etoolbox-pkg] 提供的补丁来实现。但是，即使更改仅限于环境，其他\itshape用途也会对 进行更改\upshape。在这种情况下，也许这不是问题。

\documentclass{article}
\usepackage{etoolbox}% http://ctan.org/pkg/etoolbox
\newenvironment{definition}%
  {\itshape}% \begin{definition}
  {}% \end{definition}
\begin{document}
% Normal definition
\begin{definition}
  This is a definition, in which I would like to have a few normal words.
\end{definition}

% Manually corrected definition
\begin{definition}
  \upshape This is a definition, in which I would like to have a few normal words.
\end{definition}

\AtBeginEnvironment{definition}{\renewcommand{\itshape}{\upshape}}% You can also place this in your document preamble
% Automatically corrected definition
\begin{definition}
  This is a definition, in which I would like to have a few normal words.
\end{definition}

\end{document}