Reset counter value within new paragraph

Question

The \newcounter{<counter-name>}[<outer-counter>] commands will define a new counter. For example, \newcounter{example}[section] command creates a new counter called example that will be reset every time the section counter is increased.

But for paragraph counter, the \newcounter{<counter-name>}[paragraph] doesn't work.

Here is the MWE:

\documentclass{article}


\newcounter{sentencenum}[paragraph]
\newcommand{\sno}[0]{\refstepcounter{sentencenum}$_{\arabic{sentencenum}}$}


\begin{document}


\sno{}Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
\sno{}Ut purus elit, vestibulum ut, placerat ac,adipiscing vitae, felis. Curabitur dictum gravida mauris.
\sno{}Nam arcu libero, nonummy eget, consectetuerid, vulputate a, magna.
\sno{}Donec vehicula augue eu neque. Pellentesque habitant morbi tristique senectus etnetus et malesuada fames ac turpis egestas.
\sno{}Mauris ut leo. Cras viverra metus rhoncus sem.
\sno{}Nulla et lectusvestibulum urna fringilla ultrices.
\sno{}Phasellus eu tellus sit amet tortor gravida placerat.
\sno{}Integer sapien est,iaculis in, pretium quis, viverra ac, nunc.
\sno{}Praesent eget sem vel leo ultrices bibendum.
\sno{}Aenean faucibus.
\sno{}Morbi dolor nulla, malesuada eu, pulvinar at, mollis ac, nulla.
\sno{}Curabitur auctor semper nulla.
\sno{}Donec variusorci eget risus. Duis nibh mi, congue eu, accumsan eleifend, sagittis quis, diam. Duis eget orci sit amet orcidignissim rutrum.



%
% Bug: The second paragraph should reset the counter value of `sentencenum` since here start a new paragraph
%
\sno{}Nam dui ligula, fringilla a, euismod sodales, sollicitudin vel, wisi.
\sno{}Morbi auctor lorem non justo.
\sno{}Namlacus libero, pretium at, lobortis vitae, ultricies et, tellus.
\sno{}Donec aliquet, tortor sed accumsan bibendum,erat ligula aliquet magna, vitae ornare odio metus a mi.
\sno{}Morbi ac orci et nisl hendrerit mollis.
Suspendisseut massa.


\end{document}

Answer 1

I can't say that this is a recommended way to do that but could solve this problem. Please test it in more complex documents because I can't really know the side effects. Here is the code on your example:

\documentclass{article}



\newcounter{sentencenum}
\newcommand{\sno}[0]{\refstepcounter{sentencenum}$_{\arabic{sentencenum}}$}

\let\oldpar\par
\def\par{\setcounter{sentencenum}{0}\oldpar}


\begin{document}


\sno{}Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
\sno{}Ut purus elit, vestibulum ut, placerat ac,adipiscing vitae, felis. Curabitur dictum gravida mauris.
\sno{}Nam arcu libero, nonummy eget, consectetuerid, vulputate a, magna.
\sno{}Donec vehicula augue eu neque. Pellentesque habitant morbi tristique senectus etnetus et malesuada fames ac turpis egestas.
\sno{}Mauris ut leo. Cras viverra metus rhoncus sem.
\sno{}Nulla et lectusvestibulum urna fringilla ultrices.
\sno{}Phasellus eu tellus sit amet tortor gravida placerat.
\sno{}Integer sapien est,iaculis in, pretium quis, viverra ac, nunc.
\sno{}Praesent eget sem vel leo ultrices bibendum.
\sno{}Aenean faucibus.
\sno{}Morbi dolor nulla, malesuada eu, pulvinar at, mollis ac, nulla.
\sno{}Curabitur auctor semper nulla.
\sno{}Donec variusorci eget risus. Duis nibh mi, congue eu, accumsan eleifend, sagittis quis, diam. Duis eget orci sit amet orcidignissim rutrum.



%
% Bug: The second paragraph should reset the counter value of `sentencenum` since here start a new paragraph
%
\sno{}Nam dui ligula, fringilla a, euismod sodales, sollicitudin vel, wisi.
\sno{}Morbi auctor lorem non justo.
\sno{}Namlacus libero, pretium at, lobortis vitae, ultricies et, tellus.
\sno{}Donec aliquet, tortor sed accumsan bibendum,erat ligula aliquet magna, vitae ornare odio metus a mi.
\sno{}Morbi ac orci et nisl hendrerit mollis.
Suspendisseut massa.


\end{document}

The idea is:

For every new paragraph in latex, the \par command is executed. So, I added the functionality of making zero your counter by redefining \par (seems dangerous to me in first thinking about... but MAY BE it is ok....)

PS: Paragraph of text is created with empty lines between text ... But there is a sectioning command \paragraph too that you "tried to use" by mistake in your MWE.