我正在为某人输入一篇数学文章。他让我用纯 TeX（而不是 LaTeX）输入，因为他习惯使用纯 TeX，我想他想让我编辑一下我输入的内容。
无论如何，我对纯 TeX 还不熟悉。在每个部分的开头我都使用\beginsection。但是当文本超出行长时，行不会中断。有没有办法改变命令\beginsection，让它在行末中断行？
谢谢，niv
答案1
\beginsection这是from的定义plain.tex：
\outer\def\beginsection#1\par{\vskip\z@ plus.3\vsize\penalty-250
\vskip\z@ plus-.3\vsize\bigskip\vskip\parskip
\message{#1}\leftline{\bf#1}\nobreak\smallskip\noindent}
这意味着标题确实设置在 内\leftline，不允许换行。如何修改它？删除\leftline但添加 的本地设置，\interlinepenalty以便由节标题形成的段落不会跨页分割。
\catcode`@=11
\outer\def\beginsection#1\par{%
\vskip\z@ plus.3\vsize % a generous stretchability
\penalty-250 % a good point to break a page
\vskip\z@ plus-.3\vsize % but cancel it if no page break is taken at the penalty
\bigskip\vskip\parskip % separation from the above text if no page break
\message{#1}% log the section title
\begingroup
\interlinepenalty=10000 % no page break allowed in the title if split across lines
\hangindent=\parindent \hangafter=1 % indent all lines like the first one
\bf#1\par
\endgroup
\nobreak % no page break between the title and the following text
\smallskip
\noindent
}
\catcode`@=12
\vsize=6\baselineskip % just to show that no break is taken
\beginsection This is a long title that should be split across lines; just
make it sufficiently long; maybe this long is sufficient
Text of the section
\beginsection
This is a long title that should be split across lines; just
make it sufficiently long; maybe this long is sufficient
This is a long title that should be split across lines; just
make it sufficiently long; maybe this long is sufficient
This is a long title that should be split across lines; just
make it sufficiently long; maybe this long is sufficient
Text of the section
\bye
