☰

如何从 Plain TeX 文件中读取计数器寄存器？

tag-icon • tag-icon counters plain-tex external-files auxiliary-files registers
如何从 Plain TeX 文件中读取计数器寄存器？

我是一名 TeX 用户，我想从辅助文件中读取一个数字，以便实现以下功能：在页脚处打印“页码 X，总页数”。我尝试使用原始命令 \openin 和 \read，但 \read 只能将文本读入宏（根据 TeXbook 第 217 页），我不知道如何将文件中的数字读入计数寄存器。

有什么提示吗？提前致谢。

答案1

读取上次运行中所写入的文件。

\input plipsum % for mock text

% save the total page number in a file (hook into \bye)
\outer\def\bye{\par\vfill\supereject\writetotal\end}
\def\writetotal{%
  \immediate\openout\totalfile=\jobname.tot
  \immediate\write\totalfile{\the\pageno}%
  \immediate\closeout\totalfile
}
\newwrite\totalfile
\newread\totalread

% at the start we read the file
\openin\totalread=\jobname.tot
\ifeof\totalread
  % the file doesn't exist
  \def\totalpage{0}%
\else
  % define \totalpage to the contents of the first line in the tot file
  \read\totalread to \totalpage
  % it will have a space at the end
\fi
\closein\totalread

\footline{\hfil Page number \folio\ out of total \totalpage\unskip\hfil}

\lipsum{1-40}

\bye

如果你坚持要有一个计数寄存器，只需设置它：

\input plipsum

\outer\def\bye{\par\vfill\supereject\writetotal\end}
\def\writetotal{%
  \immediate\openout\totalfile=\jobname.tot
  \immediate\write\totalfile{\the\pageno}%
  \immediate\closeout\totalfile
}
\newwrite\totalfile
\newread\totalread
\newcount\totpages

\openin\totalread=\jobname.tot
\ifeof\totalread
  \def\totalpage{0}%
\else
  \read\totalread to \totalpage
\fi
\totpages=\totalpage
\closein\totalread

\footline{\hfil Page number \folio\ out of total \number\totpages\hfil}

\lipsum{1-40}

\bye

相关内容