[Tex/LaTex] Automatic Paragraph Numbers (\everypar only for paragraphs and not for \section and so on)

numberingparagraphs

I want to write a specification and each paragraph should automatically be numbered. I found something similar in a book about fitness training:

I prepared a small MWE (two-sided layout):

\documentclass{book}

\usepackage[english]{babel}
\usepackage[toc]{blindtext}

\begin{document}

\Blinddocument

\end{document}

Sadly I do not have a starting point for a solution. A manual solution would be to use margin notes.

Ideally the solution does not include a command I have to write before
every paragraph.

Update 1

Question/Answer Numbered paragraphs is pretty close:

\documentclass{article}
\usepackage[excludeor]{everyhook}
\usepackage{lipsum}
\usepackage{parskip} % I added this, Manuel Kuehner
\newcounter{paragraphs}[section]
\begin{document}
\PushPostHook{par}{%
        \stepcounter{paragraphs}%
        \llap{\thesection.\theparagraphs\ \kern\parindent}%
}
\section{Foo}
\lipsum
\section{Bar}
\lipsum
\end{document}

It creates an output like this:

So the output is not correct.

The problem is here that every section etc. also gets the additional
numbering.

Update 2

Here's another close solution (in German): http://texwelt.de/wissen/fragen/5020

But there's the same problem that I need to use a command for every number.

Update 3 [2020-11-07, i. e. 5 Years later]

After using/trying this for about 1.5 years I stopped it.
In hindsight, the comments (@egreg for example) were right and it used too many unwanted side effects.
I am sorry that I do not have a better update.
I ended up using \subsubparagraph and used it for every paragraph with a different formatting compared to the rest of the headings.

Best Answer

One approach using the linguex package:

\documentclass{article}
\usepackage{lipsum} % for dummy text    
\usepackage{linguex}
% Counter format 
\renewcommand{\ExLBr}{\bfseries}
\renewcommand{\ExRBr}{}
% http://tex.stackexchange.com/a/57279/11604
% Reset \ex. at each section 
\usepackage{chngcntr}
\counterwithin{ExNo}{section}
% add section counter
\renewcommand{\Exarabic}{\thesection.\arabic} 
\begin{document}
\section{First section}
\ex. \lipsum[2]\par
\ex. \lipsum[3]\par
\section{Second section}
\ex. \lipsum[3]\par
\end{document}

Edit: If yo do not want any command starting the paragraphs, use \everypar at your own risk ... you are warned in the comments.

In the next MWE, the macro \NumPar at the beginning of each section produce the same output that above. As example of the problems about using \everypar, note that a new section cancel the numeration but do not restore the default indentation of 1em, so you must restore it manually.

\documentclass{article}
\usepackage{lipsum}
\parindent1em
\begin{document}
\def\NumPar{%
\parskip0.5em%
\parindent0em%
\everypar={%
\hangindent3em%
\addtocounter{subsection}{1}%
\makebox[3em][l]{\bfseries\thesubsection}%
}}%
\section{First section}
\NumPar
\lipsum[2]\par
\lipsum[3]\par
\everypar{}
\lipsum[3]\par
\section{Second section}
\NumPar % Or \parindent1em to return to normal paragraphs
\lipsum[3]\par
\lipsum[3]\par
\end{document}

Related Solutions

[Tex/LaTex] Remove section numbers only from title

You can do this more simply by defining a personal command. This is the simplest way:

\newcommand{\problem}{%
  \refstepcounter{section}%
  \section*{Problem \thesection}}

Here's a skeleton document:

\documentclass{article}

\usepackage{amsmath}

\newcommand{\problem}{%
  \refstepcounter{section}%
  \section*{Problem \thesection}}

\numberwithin{equation}{section}

\begin{document}

\problem\label{easy}

Compute the following expression:
\begin{equation}\label{compute}
1+1
\end{equation}

\problem\label{difficult}

Using the result obtained from~\eqref{compute} in Problem~\ref{easy}, 
express
\begin{equation}
\int_{0}^{x} e^{-t^2}\,dt
\end{equation}
in terms of elementary functions.

\end{document}

enter image description here

There are many possible refinements. For example, you seem to want to have sequences of problems. Here's an attempt at it:

\documentclass{article}

\usepackage{amsmath,xparse}

\NewDocumentCommand{\problem}{ s }
 {%
  \IfBooleanTF{#1}
   {\refstepcounter{subproblem}%
    \section*{Problem \thesubproblem}}%
   {\refstepcounter{section}%
    \section*{Problem \thesection}}%
 }


\newcounter{subproblem}[section]
\renewcommand{\thesubproblem}{\thesection\alph{subproblem}}
\numberwithin{equation}{section}

\begin{document}

\problem\label{easy}

Compute the following expression:
\begin{equation}\label{compute-easy}
1+1
\end{equation}

\problem*\label{less-easy}
Compute the following expression:
\begin{equation}\label{compute-less-easy}
1-1
\end{equation}

\problem\label{difficult}

Using the result obtained in~\eqref{compute-easy} and 
Problem~\ref{less-easy}, express
\begin{equation}
\int_{0}^{x} e^{-t^2}\,dt
\end{equation}
in terms of elementary functions.

\end{document}

A “main problem” is started with \problem, while a “subproblem” is started with \problem*. The equation number will still be the one established by the main problem.

Avoiding the explicit number in the command allows for easily change the order of the problem, by just shuffling around their texts.

enter image description here

[Tex/LaTex] Automaticaly add paragraph spacing only between two textual paragraphs

The parskip package aims to allow setting for a non zero \parskip with the standard classes while reducing the number of places unwanted space appears. Alternatively more extensive classes such as the koma classes have design options incorporating non zero parskip.

\documentclass[parskip=half]...

for example.

Using \\ at the end of a paragraph does not add vertical space, it forces a spurious extra line of the paragraph that is an empty box the width of the page (which is why you get an underfull box warning). Such boxes to not act well at page breaks (or anywhere else).