☰

段落末尾加了一行，以破折号结尾

tag-icon • tag-icon line-breaking paragraphs warnings punctuation
段落末尾加了一行，以破折号结尾

考虑以下示例（Plain TeX）：

%%%%%

Tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt-

Test.

\end

%%%%%

第一行生成一个以破折号结尾的段落，其中有（小）溢出。出于某种奇怪的原因，TeX 在本段后留下了一个额外的（空）行（日志文件中相应的消息为“Underfull \hbox (badness 10000)”）。对这种行为有什么解释吗？TIA

答案1

似乎是因为连字符暗示了其后有一个可自由选择的换行符。由于不管怎样，行都已经满了，所以换行符被采用，留下一个单独的空格标记，该标记最终占据一行。

如果你插入

\showboxbreadth=999
\showboxdepth=999
\showlists

在长行之后（中间有一个空白行），您将在日志文件中看到以下内容：

### vertical mode entered at line 0
### current page:
\glue(\topskip) 3.16669
\hbox(6.83331+0.0)x469.75499
.\hbox(0.0+0.0)x20.0
.\tenrm T
.\tenrm t
.\tenrm t
…
.\tenrm t
.\tenrm t
.\tenrm -
.\discretionary
.\glue(\rightskip) 0.0
.\rule(*+*)x5.0
\penalty 400
\glue(\baselineskip) 12.0
\hbox(0.0+0.0)x469.75499
.\glue(\rightskip) 0.0
total height 22.0
 goal height 643.20255
prevdepth 0.0, prevgraf 2 lines

有趣的是，那里没有\parfillskip，所以我的理论可能缺少一些谜题。但是如果将破折号替换为，您确实会得到相同的结果\discretionary{}{}{}。

答案2

TeX 会因为破折号而断线。您可以使用\hbox来避免这种情况。如果您以这种方式结束该行

...tttttt\hbox{-}

多余的线就会消失。

最小示例（使用 pdfTeX 而不是 pdfLaTeX 进行编译）：

%%%%%

Tttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt\hbox{-}

Test.

\end

%%%%%

相关内容