【LaTeX Tips】如何确定某个宏定义的位置

我们在排错的时候，经常希望知道出错的宏是在哪里定义的，然后通过比对定义和现有情况判断错误原因。

LeoLiu 在 TeX.SX 给出了一个利用 filehook 宏包实现的方法，效果拔群！当然，方法有些讨巧。

代码：

\documentclass{article}
\usepackage{filehook,currfile}
\newwrite\finder
\immediate\openout\finder=\jobname.fnd

\def\searchmacro#1{
  \AtBeginOfFiles{\ifdefined#1
      \expandafter\def\csname \currfilename:found\endcsname{}%
    \fi}
  \AtEndOfFiles{\ifdefined#1
      \unless\ifcsname \currfilename:found\endcsname
        \immediate\write\finder{found in '\currfilename'}%
    \fi\fi}}

\searchmacro\url

\usepackage{hyperref}
\begin{document}
dummy
\end{document}

编译后，在 \jobname.fnd 里我们能找到

found in 'url.sty'
found in 'hyperref.sty'

也就是说，\url 是在 url.sty 里定义的，而 url.sty 被 hyperref.sty 调用。

---

We would be glad to know where a certain macro is defined, when we are debugging. LeoLiu provided a method by using the package filehook, on the website TeX.SX. It's really great!

The code is somewhat tricky:

\documentclass{article}
\usepackage{filehook,currfile}
\newwrite\finder
\immediate\openout\finder=\jobname.fnd

\def\searchmacro#1{
  \AtBeginOfFiles{\ifdefined#1
      \expandafter\def\csname \currfilename:found\endcsname{}%
    \fi}
  \AtEndOfFiles{\ifdefined#1
      \unless\ifcsname \currfilename:found\endcsname
        \immediate\write\finder{found in '\currfilename'}%
    \fi\fi}}

\searchmacro\url

\usepackage{hyperref}
\begin{document}
dummy
\end{document}

After compiling, we will get

found in 'url.sty'
found in 'hyperref.sty'

in \jobname.fnd. That is to say, \url is defined in url.sty, which is inputed by hyperref.sty.