[Tex/LaTex] Why is \linebreak failing

line-breaking

Consider the following minimal, using \linebreak:

\documentclass{article}
\begin{document}
It is impossible to say how first the idea entered
my brain, but, once conceived, it haunted me day
and night. \linebreak

Object there was none. 

\tt\meaning\linebreak
\end{document}

This produces the output,

enter image description here

I am interested to find out how the explanation of this behaviour. Is LaTeX2e buggy in this respect?

Edit

Based on the suggestions in the answers, I had another look at the TeXBook and it appears the behaviour is embedded in TeX's algorithm, quoting:

Question In one of the paragraphs earlier in this chapter, the author used \break to force a line break in a specific place; as a
result, the third line of that particular paragraph was really spaced
out. Explain why all the extra space went into the third line,
instead of being distributed impartially among the first three lines.

answer Distributing the extra space evenly would lead to three lines of the maximum badness (10000). It's better to have just one bad
line instead of three, since TeX doesn't distinguish degrees of
badness when lines are really awful. In this particular case the
\tolerance was 200, so TeX didn't try any line breaks that would
stretch the first two lines; but even if the tolerance had been raised
to 10000, the optimum setting would have had only one underfull line.
If you really want to spread the space evenly you can do so by using
\spaceskip to increase the amount of stretchability between words.

Of course I was wrong in titling the question a failing and apologies to the LaTeX Team and Knuth. However, I still have a feeling that the algorithm has room for improvement in this edge cases or at least \linebreak could be given a better semantic name \maybebreak can be one of them.

Best Answer

\linebreak[<value>]
Terminates the current line and formats it in the same way as the preceding line. If that line is justified, this line would be justified as well. The optional argument <value> takes integer values between 0 and 4 inclusive to specify the urgency of the line break; 4 means it must occur.

by the way: \linebreak has the same behaviour as \pagebreak for the vertical adjustment.

Related Solutions

[Tex/LaTex] Penalty or badness for linebreak near start or end of sentence

That's actually pretty hard to do in TeX. The penalty for hyphenating words or for breaking on a word space are per-paragraph settings so to change them mid-sentence you may have to make some compromises.

The easiest thing to do would be to stick the start of the sentence in a box

\mbox{2. The problem} is when it's broken

will not break after the the however this is an absolute prevention of breaking so probably will cause over-full boxes or bad line breaks and even if the line break happens at a good place it prevents the word space stretching or shrinking so will give uneven spacing within the line.

The linebreak penalty at a word space can be controlled if you insert explicit penalty so you can go

2.\nolinebreak[2] The\nolinebreak[2] problem\nolinebreak[2] is when it's broken

which will discourage linebreaks at the first two spaces (you could use some macro to parse ahead to find the first two or three spaces in each footnote and add these automatically) but this doesn't affect hyphenation so probably makes it more likely that teh word hyphenates (since breaking after the word is less desirable). Obviously The won't hyphenate anyway but in general that may be a concern. It may be best to prevent hyphenation by boxing each word separately.

2.\nolinebreak[2] \mbox{The}\nolinebreak[2] \mbox{problem}\nolinebreak[2] is when it's broken

Again, a macro could be inserted into your footnote code that did this automatically for the first two or three words.

Something like

\def\myfootnote#1{\footnote{\threewords#1}}

\def\threewords#1 #2 #3 {%
\mbox{#1}\nolinebreak[2]
\mbox{#2}\nolinebreak[2]
\mbox{#3} }

But perhaps with some extra checks in case the footnote does not have three spaces in it.

[Tex/LaTex] Underfull hbox in tabular

If \raggedright is acceptable...

\documentclass[twocolumn]{article}

\begin{document}
\begin{table}
 \begin{tabular}{|p{0.25\columnwidth}|p{0.75\columnwidth}|}
    \hline
\raggedright % PS
    longish line of text & second cell that will often have a lot of text\\
    \hline
  \end{tabular}
\end{table}
\end{document}

A second version:

\documentclass[twocolumn]{article}
\usepackage{array}

\begin{document}
\begin{table}
 \begin{tabular}{|>{\raggedright}p{0.25\columnwidth}|p{0.75\columnwidth}|}
    \hline
%\raggedright % PS
    longish line of text & second cell that will often have a lot of text\\
    \hline
  \end{tabular}
\end{table}


\end{document}

And you'd better add Werner's corrections.

Best Answer

Related Solutions

[Tex/LaTex] Penalty or badness for linebreak near start or end of sentence

[Tex/LaTex] Underfull hbox in tabular

Related Question