title: How do I get Emacs to fill sentences, but not paragraphs?
body: <p>I've <a href="https://stackoverflow.com/questions/539791/tips-for-collaboratively-editing-a-latex-document/539848#539848">seen</a> at least two <a href="https://stackoverflow.com/questions/193298/best-practices-in-latex/196724#196724">recommendations</a> on StackOverflow to insert newlines between sentences when editing LaTeX documents. The reason being that the practice facilitates source control, <code>diff</code>ing, and collaborative editing.</p>
  
  <p>I'm basically convinced, but I'm lazy, and I don't want to have to think about it.</p>
  
  <p>So I'm searching for some emacs incantation to handle it for me. Could be a minor mode, could be a set of variables that need to be set.</p>
  
  <p>I think what I <em>don't</em> want is</p>
  
  <ul>
  <li>Soft wrapping of text (say using the <a href="http://www.emacswiki.org/emacs/LongLines" rel="noreferrer">longlines</a> and <code>(set long-lines-auto-wrap 't)</code>). This is because I don't want to impose requirements on my collaborators' editors, and <em>I</em> sometimes use other unix tools to examine these files.</li>
  </ul>
  
  <p>I think what I <em>do</em> want is</p>
  
  <ul>
  <li>For <code>fill-paragraph</code> to fill between newlines that look like they mark the end of a sentence. </li>
  <li>A solution that works with <code>auto-fill-mode</code> would be a bonus.</li>
  </ul>
  
  <p>That is:</p>
  
  <blockquote>
    <p>chat chat chat.<br>
    A new sentence<br>
    with goofed up wrapping that needs to be fixed.<br>
    Mumble mumble  </p>
  </blockquote>
  
  <p>Transformed to:</p>
  
  <blockquote>
    <p>chat chat chat.<br>
    A new sentence with goofed up wrapping that needs to be fixed.<br>
    Mumble mumble  </p>
  </blockquote>
  
  <p>Your comments and suggestions are appreciated.</p>
  
  <hr>
  
  <p>Edit: The suggestion by <a href="https://stackoverflow.com/questions/539984/how-do-i-get-emacs-to-fill-sentences-but-not-paragraphs/540760#540760">Jouni K. Seppänen</a> pointed me at <code>LaTeX-fill-break-at-separators</code>, which suggests that emacs almost knows how to do this already. Anyway, I'm off to read some code, and will report back. Thanks again.</p>
  
  <hr>
  
  <p>More general version of the same question: <a href="https://stackoverflow.com/questions/543379/editor-showdown-maintain-newlines-at-the-ends-of-sentences">Editor showdown: Maintain newlines at the ends of sentences</a>. Thanks, <a href="https://stackoverflow.com/users/4234/dreeves">dreeves</a>.</p>