% \iffalse meta-comment
% noindentafter.dtx
%<*identify>
%
%  noindentafter -- purposefully prevention of paragraph indentation
%
%% ----------------------------------------------------------------------------
%%
%% Copyright (C) Michiel Helvensteijn, 2014-2021
%% Copyright (C) Falk Hanisch <hanisch.latex@outlook.com>, 2021-2021
%%
%% ----------------------------------------------------------------------------
%%
%% This work may be distributed and/or modified under the conditions of the
%% LaTeX Project Public License, version 1.3c of the license. The latest
%% version of this license is in
%%     http://www.latex-project.org/lppl.txt
%% and version 1.3c or later is part of all distributions of
%% LaTeX version 2008-05-04 or later.
%%
%% This work has the LPPL maintenance status "author-maintained".
%%
%% The current maintainer and author of this work is Falk Hanisch.
%%
%% This work consists of the main source file README.md, LICENSE.md,
%% noindentafter.dtx and the derived documentation noindentafter.pdf
%%
%% ----------------------------------------------------------------------------
%%
%</identify>
% \fi
%
% \iffalse
%<*dtx>
\ifx\documentclass\undefined
\input docstrip.tex
\keepsilent

\preamble

noindentafter -- purposefully prevention of paragraph indentation

\endpreamble
\askforoverwritefalse
\usedir{tex/latex/noindentafter}
\generate{%
  \usepreamble\defaultpreamble
  \file{noindentafter.sty}{
    \from{noindentafter.dtx}{package,identify}
    \from{noindentafter.dtx}{package,body}
  }
}
\else
\let\endbatchfile\relax
\fi
\endbatchfile
%</dtx>
% \fi
%
% \iffalse
%<*dtx|package&identify>
\NeedsTeXFormat{LaTeX2e}[2020-10-01]
%<*dtx>
\ifx\ProvidesFile\undefined\def\ProvidesFile#1[#2]{}\fi
\ProvidesFile{noindentafter.dtx}
%</dtx>
%<package&identify>\ProvidesPackage{noindentafter}
  [2021-05-14 v1.00 purposefully prevention of paragraph indentation]
%</dtx|package&identify>
% \fi
%
% \iffalse
%<*dtx>
\documentclass[english,xindy]{tudscrdoc}
\KOMAoptions{parskip=false}
\usepackage{iftex}
\iftutex
  \usepackage{fontspec}
\else
  \usepackage[T1]{fontenc}
\fi
\usepackage{babel}
% normalized vskip for listings
\newlength\niavskip
\AtBeginDocument{%
  \ifdim\parskip>\bigskipamount%
    \setlength\niavskip{\parskip}%
  \else%
    \setlength\niavskip{\bigskipamount}%
  \fi%
}
\newcommand*\nianormalizedvskip{\vskip\glueexpr\niavskip-\parskip\relax}
% listings style
\usepackage{xcolor}
\usepackage{quoting}
\usepackage{listings}
\lstset{%
  inputencoding=utf8,extendedchars=true,%
  literate=%
    {ä}{{\"a}}1 {ö}{{\"o}}1 {ü}{{\"u}}1
    {Ä}{{\"A}}1 {Ö}{{\"O}}1 {Ü}{{\"U}}1
    {ß}{{\ss}}1 {~}{{\textasciitilde}}1
    {»}{{\guillemetright}}1 {«}{{\guillemetleft}}1
}
\lstdefinestyle{noindentafter}{%
  language=[LaTeX]tex,%
  columns=flexible,%
  frame=single,%
  xleftmargin=\fboxsep,%
  xrightmargin=\fboxsep,%
  escapechar=§,%
  aboveskip=\niavskip,%
  belowskip=0pt,%
  backgroundcolor=\color{yellow!10},%
  basicstyle=\color{darkgray}\small\ttfamily,%
  moretexcs=[2]{NoIndentAfterThis,NoIndentAfterCmd,NoIndentAfterEnv},%
  texcsstyle=*\color{black},%
  texcsstyle=*[2]\color{red}\bfseries,%
}
\lstnewenvironment{niaexample}[1][]{%
  \lstset{style=noindentafter,#1}%
}{%
  \nianormalizedvskip%
}
\makeatletter
% suppress overwriting warning
\providecommand*\filec@ntents@silent{%
  \let\@latex@warning@no@line\@gobble%
}
% environment for listing and inclusion, unused guard <manual> necessary
\newenvironment{niashow}{%
  \csuse{filecontents*}[force,nosearch,silent]{\jobname-lst.aux}%
}{%
  \csuse{endfilecontents*}%
}%
\AfterEndEnvironment{niashow}{%
  \begin{quoting}[rightmargin=0pt,vskip=0pt]
  \lstinputlisting[style=noindentafter]{\jobname-lst.aux}%
  \nianormalizedvskip%
  \input{\jobname-lst.aux}%
  \nianormalizedvskip%
  \end{quoting}%
}
\newcommand*\niaagain[1][\relax]{%
  #1%
  \begin{quoting}[rightmargin=0pt,vskip=0pt]
  \nianormalizedvskip%
  \input{\jobname-lst.aux}%
  \nianormalizedvskip%
  \end{quoting}%
}
% TODO l3doc + l3build
\NewDocumentCommand\DescribeMacroExtended{m !o}{%
  \ifhmode%
    \vskip\niavskip%
  \else%
    \addpenalty{\@beginparpenalty}%
    \addvspace{\niavskip}%
  \fi%
  \noindent%
  \DescribeMacro{#1}%
  \IfValueT{#2}{%
    \expandafter\cs\expandafter{\expandafter\@gobble\string#1}#2%
    \vskip\smallskipamount%
  }%
  \noindent\ignorespaces%
}
\makeatother

\usepackage{bookmark}
\usepackage[babel]{microtype}

\usepackage{noindentafter}
\NoIndentAfterEnv{niaexample}
\NoIndentAfterEnv{niashow}
\NoIndentAfterCmd{\niaagain}


%\EnableCrossrefs
\CodelineIndex
\RecordChanges
\GetFileInfo{noindentafter.dtx}



\begin{document}
  \title{The package \pkg{noindentafter}}
  \author{%
    Michiel Helvensteijn (2014-2021)\\%
    Falk Hanisch (2021--)\\%
    \url{https://github.com/mrpiggi/noindentafter}\\%
    \mailto{hanisch.latex@outlook.com}%
  }
  \date{\fileversion\nobreakspace(\filedate)}
  \maketitle%
  \begin{abstract}
    \noindent
    For certain environments---such as \env{itemize} or \env{theorem}---as 
    well as specific commands, indentation of the following paragraph is not 
    desired. It is of course possible to manually add \cs{noindent} to each 
    occurrence, but it is very easy to forget this at one point or another.
    This package provides a few simple commands which can be used to patch 
    existing macros and environments in order to get rid of manually using 
    \cs{noindent} after these. Therefore, both packages \pkg{etoolbox} and 
    \pkg{xpatch} are required.
  \end{abstract}
  %\tableofcontents
  \setcounter{secnumdepth}{0}
  \DocInput{\filename}
\end{document}
% \fi
%
\changes{v0.0.1}{2013-08-02}{initial version by Michiel Helvensteijn}
\changes{v0.2.0}{2014-11-30}{new implementation, fixing a spacing issue}
\changes{v0.2.2}{2014-11-30}{fixed version number in the README}
\changes{v1.00}{2021-05-11}{new maintainer: Falk Hanisch}^^A
\changes{v1.00}{2021-05-14}{fix for \LaTeXe\ 2019-10-01 and later}



\section{Usage}

The package does not provide additional options and is used in the simplest way 
possible:

\begin{niaexample}
\usepackage{noindentafter}
\end{niaexample}

In order to ensure a consistent layout throughout the document, it is 
recommended---but not mandatory---to use the commands described below within 
the preamble after loading package \pkg{noindentafter}. 



\DescribeMacroExtended{\NoIndentAfterEnv}[\marg{environment}]
This is probably the most frequently needed functionality. After using this 
command, any paragraph following such an \marg{environment} will remain 
unindented. The example below shows the default output without the involvement 
of \pkg{noindentafter}. 

\begin{niashow}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit, 
vestibulum ut, placerat ac, adipiscing vitae, felis. 

\begin{itemize}
  \item First Item
  \item Second Item
\end{itemize}
  
Curabitur dictum gravida mauris. Nam arcu libero, nonummy eget, consectetuer 
id, vulputate a, magna. Donec vehicula augue eu neque. 

Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac 
turpis egestas. Mauris ut leo. Cras viverra metus rhoncus sem. 
\end{niashow}

Once \lstinline[style=noindentafter]|\NoIndentAfterEnv{itemize}| has been 
executed, the output differs by the \emph{unintended} paragraph directly after 
the \env{itemize} environment: \niaagain[\NoIndentAfterEnv{itemize}]

Note that using the \cs{NoIndentAfterEnv} command on an environment is not the 
same as adding \cs{NoIndentAfterThis} to the end of it:^^A
\footnote{\cs{NoIndentAfterEnv} bypasses the group that surrounds environments}

\begin{niashow}
\newenvironment{mytestenv}{\itshape}{\NoIndentAfterThis}
\begin{mytestenv}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit, 
vestibulum ut, placerat ac, adipiscing vitae, felis. 
\end{mytestenv}

Curabitur dictum gravida mauris. Nam arcu libero, nonummy eget, consectetuer 
id, vulputate a, magna. Donec vehicula augue eu neque. 
\end{niashow}




\DescribeMacroExtended{\NoIndentAfterCmd}[\marg{command}]
By using \cs{NoIndentAfterCmd}, macros can be modified. There probably may not 
be many situations where this is useful, but perhaps this one:

\begin{niashow}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit:

\[ 1 + 1 = 2 \]

Ut purus elit, vestibulum ut, placerat ac, adipiscing vitae, felis. Curabitur 
dictum gravida mauris:

\NoIndentAfterCmd{\]}

\[ 2 + 2 = 4 \]

Nam arcu libero, nonummy eget, consectetuer id, vulputate a, magna. Donec 
vehicula augue eu neque. 
\end{niashow}



\DescribeMacroExtended{\NoIndentAfterThis}
Finally, this is the most primitive macro offered by the package. It forces a
paragraph break and suppresses indentation for whatever follows:

\begin{niashow}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit, 
vestibulum ut, placerat ac, adipiscing vitae, felis. Curabitur dictum gravida 
mauris. \NoIndentAfterThis Nam arcu libero, nonummy eget, consectetuer id, 
vulputate a, magna. Donec vehicula augue eu neque. 
\end{niashow}



\section{Acknowledgements}
This package resulted from \url{http://tex.stackexchange.com/q/112404} and the 
excellent responses to it by \textsc{cgnieder} and \textsc{lockstep}. Although 
it initially based on the proposed solution by \textsc{cgnieder}---as it was 
simpler and more generally applicable---the answer by \textsc{lockstep} is 
definitely worth reading.



\StopEventually{^^A
  \cleardoublepage\PrintIndex^^A
  \PrintChanges^^A
  \PrintToDos^^A
}
%
% \iffalse
%</dtx>
%<*package&body>
% \fi
%
%^^A \cleardoublepage
%^^A \appendix
% \section{Implementation}
% The only required packages are \pkg{etoolbox} as well as \pkg{xpatch}.
%    \begin{macrocode}
\RequirePackage{etoolbox}
\RequirePackage{xpatch}
%    \end{macrocode}
%
% \begin{macro}{\nia@scan}
% This command implements the main principle behind this package. It checks 
% whether it is followed by a paragraph. If so, the command \cs{par} is 
% temporarily changed using \cs{everypar}, so that the following paragraph is
% not indented. Immediately afterwards, default paragraph behavior is restored 
% with \cs{@restorepar} (from the \LaTeXe\ kernel).
%    \begin{macrocode}
\newcommand*\nia@scan{%
  \kernel@ifnextchar\par{%
    \par%
    \def\par{%
      \everypar{\setbox\z@\lastbox\everypar{}}%
      \@restorepar%
    }%
  }{}%
}
%    \end{macrocode}
% \end{macro}^^A \nia@scan
%
% \begin{macro}{\nia@afterendenv}
% This command is used for hooking into the ending routine of an environment at
% the latest possible point after \cs{ignorespaces}. It is heavily inspired by 
% David Carlisle\footnote{\url{https://tex.stackexchange.com/a/179034/38481}} 
% and uses a delimited argument in order to apply \cs{nia@scan} last. 
%
% It is invoked via hook \cs{AfterEndEnvironment} provided by \pkg{etoolbox} 
% and leaves everything between its invocation and \cs{ignorespaces}|\fi| at 
% the very end of \cs{end} unchanged---even additonal material given through 
% the same hook---and finally executes \cs{nia@scan}.
%    \begin{macrocode}
\newcommand*\nia@afterendenv{}
\def\nia@afterendenv#1\ignorespaces\fi{#1\ignorespaces\fi\nia@scan}
%    \end{macrocode}
% \end{macro}^^A \nia@afterendenv
%
% \begin{macro}{\NoIndentAfterThis}
% \begin{macro}{\NoIndentAfterCmd}
% \begin{macro}{\NoIndentAfterEnv}
% These are finally the user-level commands to activate the funtionality of 
% \pkg{noindetafter} for the given \marg{environment}/\marg{macro} as well as
% immediate execution. 
%    \begin{macrocode}
\newrobustcmd*\NoIndentAfterThis{\nia@scan\par}
\newcommand*\NoIndentAfterCmd[1]{%
  \xapptocmd#1{\NoIndentAfterThis}{}{%
    \PackageWarning{noindentafter}{%
      Patching `\string#1' failed!\MessageBreak%
      `\string\NoIndentAfterCmd{\string#1}' won't work%
    }%
  }%
}
\newcommand*\NoIndentAfterEnv[1]{\AfterEndEnvironment{#1}{\nia@afterendenv}}
%    \end{macrocode}
% \end{macro}^^A \NoIndentAfterEnv
% \end{macro}^^A \NoIndentAfterCmd
% \end{macro}^^A \NoIndentAfterThis
%
% \iffalse
%</package&body>
% \fi
%
% \Finale
%
\endinput
