% arara: pdflatex: { files: [latexindent]}
\section{defaultSettings.yaml}\label{sec:defuseloc}
 \texttt{latexindent.pl} loads its settings from \texttt{defaultSettings.yaml}. The idea
 is to separate the behaviour of the script from the internal working -- this is very
 similar to the way that we separate content from form when writing our documents in
 \LaTeX.

 If you look in \texttt{defaultSettings.yaml} you'll find the switches that govern the
 behaviour of \texttt{latexindent.pl}. If you're not sure where
 \texttt{defaultSettings.yaml} resides on your computer, don't worry as
 \texttt{indent.log} will tell you where to find it. \texttt{defaultSettings.yaml} is
 commented, but here is a description of what each switch is designed to do. The default
 value is given in each case; whenever you see \emph{integer} in \emph{this} section,
 assume that it must be greater than or equal to \texttt{0} unless otherwise stated.

 For most of the settings in \texttt{defaultSettings.yaml} that are specified as integers,
 then we understand \texttt{0} to represent `off' and \texttt{1} to represent `on'. For
 fields that allow values other than \texttt{0} or \texttt{1}, it is hoped that the
 specific context and associated commentary should make it clear which values are allowed.

\yamltitle{fileExtensionPreference}*{fields}
 \texttt{latexindent.pl} can be called to
 act on a file without specifying the file extension. For example we can call
 \begin{commandshell}
latexindent.pl myfile
\end{commandshell}
 in which case the script will look for \texttt{myfile} with the extensions specified in
 \texttt{fileExtensionPreference} in their numeric order. If no match is found, the script
 will exit. As with all of the fields, you should change and/or add to this as necessary.

 \cmhlistingsfromfile[style=fileExtensionPreference]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{fileExtensionPreference}}{lst:fileExtensionPreference}

 Calling \texttt{latexindent.pl myfile} with the (default) settings specified in
 \cref{lst:fileExtensionPreference} means that the script will first look for
 \texttt{myfile.tex}, then \texttt{myfile.sty}, \texttt{myfile.cls}, and finally
 \texttt{myfile.bib} in order\footnote{Throughout this manual, listings shown with line
 numbers represent code taken directly from \texttt{defaultSettings.yaml}.}.

 \index{backup files!extension settings}

\subsection{Backup and log file preferences}
\yamltitle{backupExtension}*{extension name}

 If you call \texttt{latexindent.pl} with the \texttt{-w} switch (to overwrite
 \texttt{myfile.tex}) then it will create a backup file before doing any indentation; the
 default extension is \texttt{.bak}, so, for example, \texttt{myfile.bak0} would be
 created when calling \texttt{latexindent.pl myfile.tex} for the first time.

 By default, every time you subsequently call \texttt{latexindent.pl} with the \texttt{-w}
 to act upon \texttt{myfile.tex}, it will create successive back up files:
 \texttt{myfile.bak1}, \texttt{myfile.bak2}, etc.

\yamltitle{onlyOneBackUp}*{integer}
 \label{page:onlyonebackup}
 \index{backup files!number of backup files}
 If you don't want a backup for every time that you call \texttt{latexindent.pl} (so you
 don't want \texttt{myfile.bak1}, \texttt{myfile.bak2}, etc) and you simply want
 \texttt{myfile.bak} (or whatever you chose \texttt{backupExtension} to be) then change
 \texttt{onlyOneBackUp} to \texttt{1}; the default value of \texttt{onlyOneBackUp} is
 \texttt{0}.
 \index{backup files!maximum number of backup files}
 \index{backup files!number of backup files}

\yamltitle{maxNumberOfBackUps}*{integer}
 Some users may only want a finite number of backup files, say at most $3$, in which case,
 they can change this switch. The smallest value of \texttt{maxNumberOfBackUps} is $0$
 which will \emph{not} prevent backup files being made; in this case, the behaviour will
 be dictated entirely by \texttt{onlyOneBackUp}. The default value of
 \texttt{maxNumberOfBackUps} is \texttt{0}.

\yamltitle{cycleThroughBackUps}*{integer}
 \index{backup files!cycle through}
 Some users may wish to cycle through backup files, by deleting the oldest backup file and
 keeping only the most recent; for example, with \texttt{maxNumberOfBackUps: 4}, and
 \texttt{cycleThroughBackUps} set to \texttt{1} then the \texttt{copy} procedure given
 below would be obeyed.

 \begin{commandshell}
copy myfile.bak1 to myfile.bak0
copy myfile.bak2 to myfile.bak1
copy myfile.bak3 to myfile.bak2
copy myfile.bak4 to myfile.bak3
\end{commandshell}
 The default value of \texttt{cycleThroughBackUps} is \texttt{0}.

\yamltitle{logFilePreferences}*{fields}
 \texttt{latexindent.pl} writes information to \texttt{indent.log}, some
 of which can be customized by changing \texttt{logFilePreferences}; see
 \cref{lst:logFilePreferences}. If you load your own user settings (see
 \vref{sec:indentconfig}) then \texttt{latexindent.pl} will detail them in
 \texttt{indent.log}; you can choose not to have the details logged by switching
 \texttt{showEveryYamlRead} to \texttt{0}. Once all of your settings have been loaded, you
 can see the amalgamated settings in the log file by switching
 \texttt{showAmalgamatedSettings} to \texttt{1}, if you wish.

 \cmhlistingsfromfile[style=logFilePreferences,]{../defaultSettings.yaml}[width=.9\linewidth,before=\centering,yaml-TCB]{\texttt{logFilePreferences}}{lst:logFilePreferences}

 When \announce{2018-01-13}{showDecorationStartCodeBlockTrace feature for log file} either
 of the \texttt{trace} modes (see \cpageref{page:traceswitch}) are active, you will
 receive detailed information in \texttt{indent.log}. You can specify character strings to
 appear before and after the notification of a found code block using, respectively,
 \texttt{showDecorationStartCodeBlockTrace} and
 \texttt{showDecorationFinishCodeBlockTrace}. A demonstration is given in
 \vref{app:logfile-demo}.%

 The log file will end with the characters given in \texttt{endLogFileWith}, and will
 report the \texttt{GitHub} address of \texttt{latexindent.pl} to the log file if
 \texttt{showGitHubInfoFooter} is set to \texttt{1}.

 Note: \texttt{latexindent.pl} no longer uses the \texttt{log4perl} module to handle the
 creation of the logfile. \announce{2021-03-14}*{no longer using log4perl}%

 Some of the options \announce{2021-06-19}*{logFilePreferences updated to include Dumper
 options} for Perl's \texttt{Dumper} module can be specified in
 \cref{lst:logFilePreferences}; see \cite{dumper} and \cite{dumperdemo} for more
 information. These options will mostly be helpful for those calling
 \texttt{latexindent.pl} with the \texttt{-tt} option described in \cref{sec:commandline}.%

\subsection{Verbatim code blocks}
\yamltitle{verbatimEnvironments}*{fields}

 A field that contains a list of environments that you would like left completely alone --
 no indentation will be performed on environments that you have specified in this field,
 see \cref{lst:verbatimEnvironments}. \index{verbatim!environments}
 \index{verbatim!commands}

 \begin{cmhtcbraster}[raster column skip=.1\linewidth]
  \cmhlistingsfromfile[style=verbatimEnvironments]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{verbatimEnvironments}}{lst:verbatimEnvironments}
  \cmhlistingsfromfile[style=verbatimCommands]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{verbatimCommands}}{lst:verbatimCommands}
 \end{cmhtcbraster}

 Note that if you put an environment in	\texttt{verbatimEnvironments} and in other fields
 such as \texttt{lookForAlignDelims} or \texttt{noAdditionalIndent} then
 \texttt{latexindent.pl} will \emph{always} prioritize \texttt{verbatimEnvironments}.

 You can, optionally, specify \announce{2021-10-30}{verbatim name feature} the
 \texttt{verbatim} field using the \texttt{name} field which takes a regular expression as
 its argument; thank you to \cite{XuehaiPan} for contributing this feature.

 For demonstration, then assuming that your file contains the environments
 \texttt{latexcode}, \texttt{latexcode*}, \texttt{pythoncode} and \texttt{pythoncode*},
 then the listings given in \cref{lst:nameAsRegex1,lst:nameAsRegex2} are equivalent.

 \begin{cmhtcbraster}[raster column skip=.1\linewidth]
  \cmhlistingsfromfile{demonstrations/nameAsRegex1.yaml}[yaml-TCB]{\texttt{nameAsRegex1.yaml}}{lst:nameAsRegex1}
  \cmhlistingsfromfile{demonstrations/nameAsRegex2.yaml}[yaml-TCB]{\texttt{nameAsRegex2.yaml}}{lst:nameAsRegex2}
 \end{cmhtcbraster}

 With reference to \cref{lst:nameAsRegex2}:
 \begin{itemize}
  \item the \texttt{name} field as specified here means \emph{any word followed by the word code,
        optionally followed by *};
  \item we have used \texttt{nameAsRegex} to identify this field, but you can use any description
        you like;
  \item the \texttt{lookForThis} field is optional, and can take the values 0 (off) or 1 (on); by
        default, it is assumed to be 1 (on).
 \end{itemize}

\yamltitle{verbatimCommands}*{fields}
 A field that contains a list of commands that are verbatim commands, for example
 \lstinline|\lstinline|; any commands populated in this field are protected from line
 breaking routines (only relevant if the \texttt{-m} is active, see
 \vref{sec:modifylinebreaks}).

 With reference to \cref{lst:verbatimCommands}, by default \texttt{latexindent.pl} looks
 for \lstinline|\verb| immediately followed by another character, and then it takes the
 body as anything up to the next occurrence of the character; this means that, for
 example, \lstinline|\verb!x+3!| is treated as a \texttt{verbatimCommands}.

 You can, optionally, specify \announce{2021-10-30}{verbatimCommands name feature} the
 \texttt{verbatimCommands} field using the \texttt{name} field which takes a regular
 expression as its argument; thank you to \cite{XuehaiPan} for contributing this feature.

 For demonstration, then assuming that your file contains the commands
 \texttt{verbinline}, \texttt{myinline} then the listings given in
 \cref{lst:nameAsRegex3,lst:nameAsRegex4} are equivalent.

 \begin{cmhtcbraster}[raster column skip=.1\linewidth]
  \cmhlistingsfromfile{demonstrations/nameAsRegex3.yaml}[yaml-TCB]{\texttt{nameAsRegex3.yaml}}{lst:nameAsRegex3}
  \cmhlistingsfromfile{demonstrations/nameAsRegex4.yaml}[yaml-TCB]{\texttt{nameAsRegex4.yaml}}{lst:nameAsRegex4}
 \end{cmhtcbraster}

 With reference to \cref{lst:nameAsRegex4}:
 \begin{itemize}
  \item the \texttt{name} field as specified here means \emph{any word followed by the word
        inline};
  \item we have used \texttt{nameAsRegex} to identify this field, but you can use any description
        you like;
  \item the \texttt{lookForThis} field is optional, and can take the values 0 (off) or 1 (on); by
        default, it is assumed to be 1 (on).
 \end{itemize}

\yamltitle{noIndentBlock}*{fields}
 If you have a block of code that you don't want \texttt{latexindent.pl} to touch (even if
 \index{verbatim!noIndentBlock} it is \emph{not} a verbatim-like environment) then you can
 wrap it in an environment from \texttt{noIndentBlock}; you can use any name you like for
 this, provided you populate it as demonstrate in \cref{lst:noIndentBlock}.

 \cmhlistingsfromfile[style=noIndentBlock]{../defaultSettings.yaml}[width=.4\linewidth,before=\centering,yaml-TCB]{\texttt{noIndentBlock}}{lst:noIndentBlock}

 Of course, you don't want to have to specify these as null environments in your code, so
 you use them with a comment symbol, \lstinline!%!, followed by as many spaces (possibly
 none) as you like; see \cref{lst:noIndentBlockdemo} for example.

 \cmhlistingsfromfile{demonstrations/noindentblock.tex}{\texttt{noIndentBlock.tex}}{lst:noIndentBlockdemo}

 Important note: it is assumed that the \texttt{noindent} block statements specified in
 this way appear on their own line.

 The \announce{2021-06-19}{noIndentBlock specified as regex} \texttt{noIndentBlock} fields
 can also be specified in terms of \texttt{begin} and \texttt{end} fields. We use the code
 in \cref{lst:noIndentBlock1} to demonstrate this feature.%

 \cmhlistingsfromfile{demonstrations/noindentblock1.tex}{\texttt{noIndentBlock1.tex}}{lst:noIndentBlock1}

 The settings given in \cref{lst:noindent1,lst:noindent2} are equivalent:

 \begin{cmhtcbraster}[raster columns=3,
   raster left skip=-3.5cm,
   raster right skip=-2cm,
   raster column skip=.03\linewidth]
  \cmhlistingsfromfile{demonstrations/noindent1.yaml}[yaml-TCB]{\texttt{noindent1.yaml}}{lst:noindent1}
  \cmhlistingsfromfile{demonstrations/noindent2.yaml}[yaml-TCB]{\texttt{noindent2.yaml}}{lst:noindent2}
  \cmhlistingsfromfile{demonstrations/noindent3.yaml}[yaml-TCB]{\texttt{noindent3.yaml}}{lst:noindent3}
 \end{cmhtcbraster}

 Upon running the commands
 \begin{commandshell}
latexindent.pl -l noindent1.yaml noindent1
latexindent.pl -l noindent2.yaml noindent1
\end{commandshell}
 then we receive the output given in \cref{lst:noIndentBlock1-mod1}.

 \cmhlistingsfromfile{demonstrations/noindentblock1-mod1.tex}{\texttt{noIndentBlock1.tex} using \cref{lst:noindent1} or \cref{lst:noindent2}}{lst:noIndentBlock1-mod1}

 The \texttt{begin}, \texttt{body} and \texttt{end} fields for \texttt{noIndentBlock} are
 all \emph{regular expressions}. If the \texttt{body} field is not specified, then it
 takes a default value of \lstinline!.*?! which is written explicitly in
 \cref{lst:noindent1}. In this context, we interpret \lstinline!.*?! in words as \emph{the
 fewest number of characters (possibly none) until the `end' field is reached}.

 The \texttt{lookForThis} field is optional, and can take the values 0 (off) or 1 (on); by
 default, it is assumed to be 1 (on).

 Using \cref{lst:noindent3} demonstrates setting \texttt{lookForThis} to 0 (off); running
 the command
 \begin{commandshell}
latexindent.pl -l noindent3.yaml noindent1
\end{commandshell}
 gives the output in \cref{lst:noIndentBlock1-mod3}.

 \cmhlistingsfromfile{demonstrations/noindentblock1-mod3.tex}{\texttt{noIndentBlock1.tex} using \cref{lst:noindent3}}{lst:noIndentBlock1-mod3}

 We will demonstrate this feature later in the documentation in \cref{lst:href3}.

 You can, optionally, specify \announce{2021-10-30}{noIndentBlock name feature} the
 \texttt{noIndentBlock} field using the \texttt{name} field which takes a regular
 expression as its argument; thank you to \cite{XuehaiPan} for contributing this feature.

 For demonstration, then assuming that your file contains the environments
 \texttt{testnoindent}, \texttt{testnoindent*} then the listings given in
 \cref{lst:nameAsRegex5,lst:nameAsRegex6} are equivalent.

 \begin{widepage}
  \begin{cmhtcbraster}[raster column skip=.1\linewidth]
   \cmhlistingsfromfile{demonstrations/nameAsRegex5.yaml}[yaml-TCB]{\texttt{nameAsRegex5.yaml}}{lst:nameAsRegex5}
   \cmhlistingsfromfile{demonstrations/nameAsRegex6.yaml}[yaml-TCB]{\texttt{nameAsRegex6.yaml}}{lst:nameAsRegex6}
  \end{cmhtcbraster}
 \end{widepage}

 With reference to \cref{lst:nameAsRegex6}:
 \begin{itemize}
  \item the \texttt{name} field as specified here means \emph{any word followed by the word
        noindent, optionally followed by *};
  \item we have used \texttt{nameAsRegex} to identify this field, but you can use any description
        you like;
  \item the \texttt{lookForThis} field is optional, and can take the values 0 (off) or 1 (on); by
        default, it is assumed to be 1 (on).
 \end{itemize}
\subsection{filecontents and preamble}
\yamltitle{fileContentsEnvironments}*{field}

 Before \texttt{latexindent.pl} determines the difference between preamble (if any) and
 the main document, it first searches for any of the environments specified in
 \texttt{fileContentsEnvironments}, see \cref{lst:fileContentsEnvironments}. The behaviour
 of \texttt{latexindent.pl} on these environments is determined by their location
 (preamble or not), and the value \texttt{indentPreamble}, discussed next.

 \cmhlistingsfromfile[style=fileContentsEnvironments]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{fileContentsEnvironments}}{lst:fileContentsEnvironments}

\yamltitle{indentPreamble}{0|1}

 The preamble of a document can sometimes contain some trickier code for
 \texttt{latexindent.pl} to operate upon. By default, \texttt{latexindent.pl} won't try to
 operate on the preamble (as \texttt{indentPreamble} is set to \texttt{0}, by default),
 but if you'd like \texttt{latexindent.pl} to try then change \texttt{indentPreamble} to
 \texttt{1}.

\yamltitle{lookForPreamble}*{fields}

 Not all files contain preamble; for example, \texttt{sty}, \texttt{cls} and \texttt{bib}
 files typically do \emph{not}. Referencing \cref{lst:lookForPreamble}, if you set, for
 example, \texttt{.tex} to \texttt{0}, then regardless of the setting of the value of
 \texttt{indentPreamble}, preamble will not be assumed when operating upon \texttt{.tex}
 files.

 \cmhlistingsfromfile[style=lookForPreamble]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{lookForPreamble}{lst:lookForPreamble}
\yamltitle{preambleCommandsBeforeEnvironments}{0|1}
 Assuming that \texttt{latexindent.pl} is asked to operate upon the preamble of a
 document, when this switch is set to \texttt{0} then environment code blocks will be
 sought first, and then command code blocks. When this switch is set to \texttt{1},
 commands will be sought first. The example that first motivated this switch contained the
 code given in \cref{lst:motivatepreambleCommandsBeforeEnvironments}.

 \begin{cmhlistings}{Motivating \texttt{preambleCommandsBeforeEnvironments}}{lst:motivatepreambleCommandsBeforeEnvironments}
...
preheadhook={\begin{mdframed}[style=myframedstyle]},
postfoothook=\end{mdframed},
...
\end{cmhlistings}

 \index{indentation!defaultIndent description}

\subsection{Indentation and horizontal space}
\yamltitle{defaultIndent}*{horizontal space}
 This is the default indentation used in the absence of other details for the code block
 with which we are working. The default value is \lstinline!\t! which means a tab; we will
 explore customisation beyond \texttt{defaultIndent} in \vref{sec:noadd-indent-rules}.

 If you're interested in experimenting with \texttt{latexindent.pl} then you can
 \emph{remove} all indentation by setting \texttt{defaultIndent: ""}.

\yamltitle{removeTrailingWhitespace}*{fields}\label{yaml:removeTrailingWhitespace}

 Trailing white space can be removed both \emph{before} and \emph{after} processing the
 document, as detailed in \cref{lst:removeTrailingWhitespace}; each of the fields can take
 the values \texttt{0} or \texttt{1}. See
 \vref{lst:removeTWS-before,lst:env-mlb5-modAll,lst:env-mlb5-modAll-remove-WS} for before
 and after results. Thanks to \cite{vosskuhle} for providing this feature.

 \begin{minipage}{.4\textwidth}
  \cmhlistingsfromfile[style=removeTrailingWhitespace]{../defaultSettings.yaml}[before=\centering,yaml-TCB]{removeTrailingWhitespace}{lst:removeTrailingWhitespace}
 \end{minipage}%
 \hfill
 \begin{minipage}{.5\textwidth}
  \begin{yaml}[numbers=none]{removeTrailingWhitespace (alt)}[before=\centering]{lst:removeTrailingWhitespace-alt}
removeTrailingWhitespace: 1
\end{yaml}
 \end{minipage}%

 You can specify \texttt{removeTrailingWhitespace} simply as \texttt{0} or \texttt{1}, if
 you wish; in this case, \announce{2017-06-28}{removeTrailingWhitespace}
 \texttt{latexindent.pl} will set both \texttt{beforeProcessing} and
 \texttt{afterProcessing} to the value you specify; see
 \cref{lst:removeTrailingWhitespace-alt}.%

\subsection{Aligning at delimiters}\label{subsec:align-at-delimiters}
\yamltitle{lookForAlignDelims}*{fields}
 This contains a list of code blocks that are operated upon in a special way by
 \texttt{latexindent.pl} (see \cref{lst:aligndelims:basic}). In fact, the fields in
 \texttt{lookForAlignDelims} can actually take two different forms: the \emph{basic}
 version is shown in \cref{lst:aligndelims:basic} and the \emph{advanced} version in
 \cref{lst:aligndelims:advanced}; we will discuss each in turn. \index{delimiters!advanced
 settings of lookForAlignDelims}

 \begin{yaml}[numbers=none]{\texttt{lookForAlignDelims} (basic)}[width=.8\linewidth,before=\centering]{lst:aligndelims:basic}
lookForAlignDelims:
   tabular: 1
   tabularx: 1
   longtable: 1
   array: 1
   matrix: 1
   ...
	\end{yaml}

 Specifying code blocks in this field instructs \texttt{latexindent.pl} to try and align
 each column by its alignment delimiters. It does have some limitations (discussed further
 in \cref{sec:knownlimitations}), but in many cases it will produce results such as those
 in \cref{lst:tabularbefore:basic,lst:tabularafter:basic}.

 If you find that \texttt{latexindent.pl} does not perform satisfactorily on such
 environments then you can set the relevant key to \texttt{0}, for example
 \texttt{tabular: 0}; alternatively, if you just want to ignore \emph{specific} instances
 of the environment, you could wrap them in something from \texttt{noIndentBlock} (see
 \vref{lst:noIndentBlock}).

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabular1.tex}{\texttt{tabular1.tex}}{lst:tabularbefore:basic}
  \cmhlistingsfromfile{demonstrations/tabular1-default.tex}{\texttt{tabular1.tex} default output}{lst:tabularafter:basic}
 \end{cmhtcbraster}

 If, for example, you wish to remove the alignment of the \lstinline!\\! within a
 delimiter-aligned block, then the advanced form of \texttt{lookForAlignDelims} shown in
 \cref{lst:aligndelims:advanced} is for you. \index{regular expressions!delimiterRegEx}
 \index{regular expressions!ampersand alignment} \index{delimiters!default settings of
 lookForAlignDelims} \index{delimiters!ampersand \&} \index{delimiters!advanced settings}
 \index{delimiters!lookForAlignDelims}

 \cmhlistingsfromfile[style=lookForAlignDelims]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{lookForAlignDelims} (advanced)}{lst:aligndelims:advanced}

 Note that you can use a mixture of the basic and advanced form: in
 \cref{lst:aligndelims:advanced} \texttt{tabular} and \texttt{tabularx} are advanced and
 \texttt{longtable} is basic. When using the advanced form, each field should receive at
 least 1 sub-field, and \emph{can} (but does not have to) receive any of the following
 fields:
 \begin{itemize}
  \item \texttt{delims}: binary switch (0 or 1) equivalent to simply specifying, for
        example, \texttt{tabular: 1} in the basic version shown in \cref{lst:aligndelims:basic}.
        If \texttt{delims} is set to \texttt{0} then the align at ampersand routine will not be
        called for this code block (default: 1);
  \item \texttt{alignDoubleBackSlash}: binary switch (0 or 1) to determine if
        \lstinline!\\!
        should be aligned (default: 1);
  \item \texttt{spacesBeforeDoubleBackSlash}: optionally,%
        \announce{2018-01-13}*{update to spacesBeforeDoubleBackSlash in ampersand alignment}
        specifies the number (integer $\geq$ 0) of spaces to be inserted before
        \lstinline!\\! (default: 1); %\footnote{Previously this only activated if \texttt{alignDoubleBackSlash} was set to \texttt{0}.}
  \item \announce{2017-06-19}{multiColumnGrouping} \texttt{multiColumnGrouping}: binary switch (0
        or 1) that details if \texttt{latexindent.pl} should group columns above and below a
        \lstinline!\multicolumn! command (default: 0);
  \item \announce{2017-06-19}{alignRowsWithoutMaxDelims} \texttt{alignRowsWithoutMaxDelims}:
        binary switch (0 or 1) that details if rows that do not contain the maximum number of
        delimeters should be formatted so as to have the ampersands aligned (default: 1);
  \item \announce{2018-01-13}{spacesBeforeAmpersand in ampersand
        alignment}\texttt{spacesBeforeAmpersand}: optionally specifies the number (integer $\geq$
        0) of spaces to be placed \emph{before} ampersands (default: 1);
  \item \announce{2018-01-13}{spacesAfterAmpersand in ampersand
        alignment}\texttt{spacesAfterAmpersand}: optionally specifies the number (integer $\geq$
        0) of spaces to be placed \emph{After} ampersands (default: 1);
  \item \announce{2018-01-13}{justification of cells in ampersand
        alignment}\texttt{justification}: optionally specifies the justification of each cell as
        either \emph{left} or \emph{right} (default: left);
  \item \announce{2020-03-21}{align final double back slash}{alignFinalDoubleBackSlash}
        optionally specifies if the \emph{final} double back slash should be used for alignment
        (default: 0);
  \item \announce{2020-03-21}{don't measure feature}{dontMeasure} optionally specifies if
        user-specified cells, rows or the largest entries should \emph{not} be measured (default:
        0);
  \item \announce{2020-03-21}{delimiter RegEx feature}{delimiterRegEx} optionally specifies the
        pattern matching to be used for the alignment delimeter (default:
        \lstinline* '(?<!\\)(&)'*);
  \item \announce{2020-03-21}{delimiter justification}{delimiterJustification} optionally
        specifies the justification for the alignment delimeters (default: left); note that this
        feature is only useful if you have delimiters of different lengths in the same column,
        discussed in \cref{sec:delimiter-reg-ex};
  \item \announce{2021-12-13}{lookForChildCodeBlocks feature}{lookForChildCodeBlocks} optionally
        instructs \texttt{latexindent.pl} to search for child code blocks or not (default: 1),
        discussed in \cref{sec:lookForChildCodeBlocks}.
 \end{itemize}

 We will explore most of these features using the file \texttt{tabular2.tex} in
 \cref{lst:tabular2} (which contains a \lstinline!\multicolumn! command), and the YAML
 files in \crefrange{lst:tabular2YAML}{lst:tabular8YAML}; we will explore
 \texttt{alignFinalDoubleBackSlash} in \cref{lst:tabular4}; the \texttt{dontMeasure}
 feature will be described in \cref{sec:dontMeasure}, and \texttt{delimiterRegEx} in
 \cref{sec:delimiter-reg-ex}.

 \cmhlistingsfromfile{demonstrations/tabular2.tex}{\texttt{tabular2.tex}}{lst:tabular2}
 \begin{minipage}{.45\textwidth}
  \cmhlistingsfromfile[style=yaml-LST]{demonstrations/tabular2.yaml}[yaml-TCB]{\texttt{tabular2.yaml}}{lst:tabular2YAML}
 \end{minipage}%
 \hfill
 \begin{minipage}{.48\textwidth}
  \cmhlistingsfromfile[style=yaml-LST]{demonstrations/tabular3.yaml}[yaml-TCB]{\texttt{tabular3.yaml}}{lst:tabular3YAML}
 \end{minipage}%

 \begin{minipage}{.45\textwidth}
  \cmhlistingsfromfile[style=yaml-LST]{demonstrations/tabular4.yaml}[yaml-TCB]{\texttt{tabular4.yaml}}{lst:tabular4YAML}
 \end{minipage}%
 \hfill
 \begin{minipage}{.48\textwidth}
  \cmhlistingsfromfile[style=yaml-LST]{demonstrations/tabular5.yaml}[yaml-TCB]{\texttt{tabular5.yaml}}{lst:tabular5YAML}
 \end{minipage}%

 \begin{minipage}{.45\textwidth}
  \cmhlistingsfromfile[style=yaml-LST]{demonstrations/tabular6.yaml}[yaml-TCB]{\texttt{tabular6.yaml}}{lst:tabular6YAML}
 \end{minipage}%
 \hfill
 \begin{minipage}{.48\textwidth}
  \cmhlistingsfromfile[style=yaml-LST]{demonstrations/tabular7.yaml}[yaml-TCB]{\texttt{tabular7.yaml}}{lst:tabular7YAML}
 \end{minipage}%

 \begin{minipage}{.48\textwidth}
  \cmhlistingsfromfile[style=yaml-LST]{demonstrations/tabular8.yaml}[yaml-TCB]{\texttt{tabular8.yaml}}{lst:tabular8YAML}
 \end{minipage}%

 On running the commands \index{delimiters!spacing demonstration} \index{switches!-l
 demonstration}
 \begin{commandshell}
latexindent.pl tabular2.tex 
latexindent.pl tabular2.tex -l tabular2.yaml
latexindent.pl tabular2.tex -l tabular3.yaml
latexindent.pl tabular2.tex -l tabular2.yaml,tabular4.yaml
latexindent.pl tabular2.tex -l tabular2.yaml,tabular5.yaml
latexindent.pl tabular2.tex -l tabular2.yaml,tabular6.yaml
latexindent.pl tabular2.tex -l tabular2.yaml,tabular7.yaml
latexindent.pl tabular2.tex -l tabular2.yaml,tabular8.yaml
\end{commandshell}
 we obtain the respective outputs given in
 \crefrange{lst:tabular2-default}{lst:tabular2-mod8}.

 \begin{widepage}
  \cmhlistingsfromfile{demonstrations/tabular2-default.tex}{\texttt{tabular2.tex} default output}{lst:tabular2-default}
  \cmhlistingsfromfile{demonstrations/tabular2-mod2.tex}{\texttt{tabular2.tex} using \cref{lst:tabular2YAML}}{lst:tabular2-mod2}
  \cmhlistingsfromfile{demonstrations/tabular2-mod3.tex}{\texttt{tabular2.tex} using \cref{lst:tabular3YAML}}{lst:tabular2-mod3}
  \cmhlistingsfromfile{demonstrations/tabular2-mod4.tex}{\texttt{tabular2.tex} using \cref{lst:tabular2YAML,lst:tabular4YAML}}{lst:tabular2-mod4}
  \cmhlistingsfromfile{demonstrations/tabular2-mod5.tex}{\texttt{tabular2.tex} using \cref{lst:tabular2YAML,lst:tabular5YAML}}{lst:tabular2-mod5}
  \cmhlistingsfromfile{demonstrations/tabular2-mod6.tex}{\texttt{tabular2.tex} using \cref{lst:tabular2YAML,lst:tabular6YAML}}{lst:tabular2-mod6}
  \cmhlistingsfromfile{demonstrations/tabular2-mod7.tex}{\texttt{tabular2.tex} using \cref{lst:tabular2YAML,lst:tabular7YAML}}{lst:tabular2-mod7}
  \cmhlistingsfromfile{demonstrations/tabular2-mod8.tex}{\texttt{tabular2.tex} using \cref{lst:tabular2YAML,lst:tabular8YAML}}{lst:tabular2-mod8}
 \end{widepage}

 Notice in particular:
 \begin{itemize}
  \item in both \cref{lst:tabular2-default,lst:tabular2-mod2} all rows have been aligned at the
        ampersand, even those that do not contain the maximum number of ampersands (3 ampersands,
        in this case);
  \item in \cref{lst:tabular2-default} the columns have been aligned at the ampersand;
  \item in \cref{lst:tabular2-mod2} the \lstinline!\multicolumn! command has grouped the $2$
        columns beneath \emph{and} above it, because \texttt{multiColumnGrouping} is set to $1$
        in \cref{lst:tabular2YAML};
  \item in \cref{lst:tabular2-mod3} rows~3 and~6 have \emph{not} been aligned at the ampersand,
        because \texttt{alignRowsWithoutMaxDelims} has been to set to $0$ in
        \cref{lst:tabular3YAML}; however, the \lstinline!\\! \emph{have} still been aligned;
  \item in \cref{lst:tabular2-mod4} the columns beneath and above the \lstinline!\multicolumn!
        commands have been grouped (because \texttt{multiColumnGrouping} is set to $1$), and
        there are at least $4$ spaces \emph{before} each aligned ampersand because
        \texttt{spacesBeforeAmpersand} is set to $4$;
  \item in \cref{lst:tabular2-mod5} the columns beneath and above the \lstinline!\multicolumn!
        commands have been grouped (because \texttt{multiColumnGrouping} is set to $1$), and
        there are at least $4$ spaces \emph{after} each aligned ampersand because
        \texttt{spacesAfterAmpersand} is set to $4$;
  \item in \cref{lst:tabular2-mod6} the \lstinline!\\! have \emph{not} been aligned, because
        \texttt{alignDoubleBackSlash} is set to \texttt{0}, otherwise the output is the same as
        \cref{lst:tabular2-mod2};
  \item in \cref{lst:tabular2-mod7} the \lstinline!\\! \emph{have} been aligned, and because
        \texttt{spacesBeforeDoubleBackSlash} is set to \texttt{0}, there are no spaces ahead of
        them; the output is otherwise the same as \cref{lst:tabular2-mod2};
  \item in \cref{lst:tabular2-mod8} the cells have been \emph{right}-justified; note that cells
        above and below the \lstinline!\multicol! statements have still been group correctly,
        because of the settings in \cref{lst:tabular2YAML}.
 \end{itemize}

\subsubsection{lookForAlignDelims: spacesBeforeAmpersand}
 The \texttt{spacesBeforeAmpersand} \announce{2021-06-19}*{spacesBeforeAmpersand leading
 blank column upgrade} can be specified in a few different ways. The \emph{basic} form is
 demonstrated in \cref{lst:tabular4YAML}, but we can customise the behaviour further by
 specifying if we would like this value to change if it encounters a \emph{leading blank
 column}; that is, when the first column contains only zero-width entries. We refer to
 this as the \emph{advanced} form.%

 We demonstrate this feature in relation to \cref{lst:aligned1}; upon running the
 following command
 \begin{commandshell}
latexindent.pl aligned1.tex -o=+-default
\end{commandshell}
 then we receive the default output given in \cref{lst:aligned1-default}.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/aligned1.tex}{\texttt{aligned1.tex}}{lst:aligned1}
  \cmhlistingsfromfile{demonstrations/aligned1-default.tex}{\texttt{aligned1-default.tex}}{lst:aligned1-default}
 \end{cmhtcbraster}

 The settings in \crefrange{lst:sba1}{lst:sba4} are all equivlanent; we have used the
 not-yet discussed \texttt{noAdditionalIndent} field (see \vref{sec:noadd-indent-rules})
 which will assist in the demonstration in what follows.
 \begin{cmhtcbraster}[raster columns=2, ]
  \cmhlistingsfromfile{demonstrations/sba1.yaml}[yaml-TCB]{\texttt{sba1.yaml}}{lst:sba1}
  \cmhlistingsfromfile{demonstrations/sba2.yaml}[yaml-TCB]{\texttt{sba2.yaml}}{lst:sba2}
  \cmhlistingsfromfile{demonstrations/sba3.yaml}[yaml-TCB]{\texttt{sba3.yaml}}{lst:sba3}
  \cmhlistingsfromfile{demonstrations/sba4.yaml}[yaml-TCB]{\texttt{sba4.yaml}}{lst:sba4}
 \end{cmhtcbraster}
 Upon running the following commands
 \begin{commandshell}
latexindent.pl aligned1.tex -l sba1.yaml
latexindent.pl aligned1.tex -l sba2.yaml
latexindent.pl aligned1.tex -l sba3.yaml
latexindent.pl aligned1.tex -l sba4.yaml
\end{commandshell}
 then we receive the (same) output given in \cref{lst:aligned1-mod1}; we note that there
 is \emph{one space} before each ampersand.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/aligned1-mod1.tex}{\texttt{aligned1-mod1.tex}}{lst:aligned1-mod1}
 \end{cmhtcbraster}

 We note in particular:
 \begin{itemize}
  \item \cref{lst:sba1} demonstrates the \emph{basic} form for
        \texttt{lookForAlignDelims}; in this case,
        the default values are specified as in \vref{lst:aligndelims:advanced};
  \item \cref{lst:sba2} demonstrates the \emph{advanced} form for
        \texttt{lookForAlignDelims}
        and specified \texttt{spacesBeforeAmpersand}. The default value is \texttt{1};
  \item \cref{lst:sba3} demonstrates the new \emph{advanced} way to specify
        \texttt{spacesBeforeAmpersand}, and
        for us to set the \texttt{default} value that sets the number of spaces before ampersands
        which are \emph{not} in leading blank columns. The default value is \texttt{1}.

        We note that \texttt{leadingBlankColumn} has not been specified in \cref{lst:sba3}, and
        it will inherit the value from \texttt{default};
  \item \cref{lst:sba4} demonstrates spaces to be used before amperands for
        \emph{leading blank columns}.
        We note that \emph{default} has not been specified, and it will be set to \texttt{1} by
        default.
 \end{itemize}
 We can customise the space before the ampersand in the \emph{leading blank column} of
 \cref{lst:aligned1-mod1} by using either of \cref{lst:sba5,lst:sba6}, which are
 equivalent.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/sba5.yaml}[yaml-TCB]{\texttt{sba5.yaml}}{lst:sba5}
  \cmhlistingsfromfile{demonstrations/sba6.yaml}[yaml-TCB]{\texttt{sba6.yaml}}{lst:sba6}
 \end{cmhtcbraster}

 Upon running
 \begin{commandshell}
latexindent.pl aligned1.tex -l sba5.yaml
latexindent.pl aligned1.tex -l sba6.yaml
\end{commandshell}
 then we receive the (same) output given in \cref{lst:aligned1-mod5}. We note that the
 space before the ampersand in the \emph{leading blank column} has been set to \texttt{0}
 by \cref{lst:sba6}.

 We can demonstrated this feature further using the settings in \cref{lst:sba7} which give
 the output in \cref{lst:aligned1-mod7}.

 \begin{cmhtcbraster}[raster columns=3,
   raster left skip=-3.75cm,
   raster right skip=-2cm,]
  \cmhlistingsfromfile{demonstrations/aligned1-mod5.tex}{\texttt{aligned1-mod5.tex}}{lst:aligned1-mod5}
  \cmhlistingsfromfile{demonstrations/aligned1-mod7.tex}{\texttt{aligned1.tex} using \cref{lst:sba7}}{lst:aligned1-mod7}
  \cmhlistingsfromfile{demonstrations/sba7.yaml}[yaml-TCB]{\texttt{sba7.yaml}}{lst:sba7}
 \end{cmhtcbraster}
\subsubsection{lookForAlignDelims: alignFinalDoubleBackSlash}
 We explore \announce{2020-03-21}{alignFinalDoubleBackSlash demonstration} the
 \texttt{alignFinalDoubleBackSlash} feature by using the file in \cref{lst:tabular4}. Upon
 running the following commands \index{delimiters!double backslash demonstration}
 \index{switches!-y demonstration} \index{switches!-o demonstration}%
 \begin{commandshell}
latexindent.pl tabular4.tex -o=+-default
latexindent.pl tabular4.tex -o=+-FDBS -y="lookForAlignDelims:tabular:alignFinalDoubleBackSlash:1"
\end{commandshell}
 then we receive the respective outputs given in \cref{lst:tabular4-default} and
 \cref{lst:tabular4-FDBS}.

 \begin{cmhtcbraster}[raster columns=3,
   raster left skip=-3.75cm,
   raster right skip=-2cm,]
  \cmhlistingsfromfile{demonstrations/tabular4.tex}{\texttt{tabular4.tex}}{lst:tabular4}
  \cmhlistingsfromfile{demonstrations/tabular4-default.tex}{\texttt{tabular4-default.tex}}{lst:tabular4-default}
  \cmhlistingsfromfile{demonstrations/tabular4-FDBS.tex}{\texttt{tabular4-FDBS.tex}}{lst:tabular4-FDBS}
 \end{cmhtcbraster}

 We note that in:
 \begin{itemize}
  \item \cref{lst:tabular4-default}, by default, the \emph{first} set of double back
        slashes in the first row of the \texttt{tabular} environment have been used for
        alignment;
  \item \cref{lst:tabular4-FDBS}, the \emph{final} set of double back slashes in the
        first row have been used, because we specified \texttt{alignFinalDoubleBackSlash} as 1.
 \end{itemize}

 As of Version 3.0, the alignment routine works on mandatory and optional arguments within
 commands, and also within `special' code blocks (see \texttt{specialBeginEnd} on
 \cpageref{yaml:specialBeginEnd}); for example, assuming that you have a command called
 \lstinline!\matrix! and that it is populated within \texttt{lookForAlignDelims} (which it
 is, by default), and that you run the command
 \begin{commandshell}
latexindent.pl matrix1.tex 
\end{commandshell}
 then the before-and-after results shown in \cref{lst:matrixbefore,lst:matrixafter} are
 achievable by default.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/matrix1.tex}{\texttt{matrix1.tex}}{lst:matrixbefore}
  \cmhlistingsfromfile{demonstrations/matrix1-default.tex}{\texttt{matrix1.tex} default output}{lst:matrixafter}
 \end{cmhtcbraster}

 If you have blocks of code that you wish to align at the \& character that are \emph{not}
 wrapped in, for example, \lstinline!\begin{tabular}! \ldots \lstinline!\end{tabular}!,
 then you can use the mark up illustrated in \cref{lst:alignmentmarkup}; the default
 output is shown in \cref{lst:alignmentmarkup-default}. Note that the \lstinline!%*! must
 be next to each other, but that there can be any number of spaces (possibly none) between
 the \lstinline!*! and \lstinline!\begin{tabular}!; note also that you may use any
 environment name that you have specified in \texttt{lookForAlignDelims}.

 \begin{cmhtcbraster}[raster left skip=-1.5cm,]
  \cmhlistingsfromfile{demonstrations/align-block.tex}{\texttt{align-block.tex}}{lst:alignmentmarkup}
  \cmhlistingsfromfile{demonstrations/align-block-default.tex}{\texttt{align-block.tex} default output}{lst:alignmentmarkup-default}
 \end{cmhtcbraster}

 With reference to \vref{tab:code-blocks} and the, yet undiscussed, fields of
 \texttt{noAdditionalIndent} and \texttt{indentRules} (see \vref{sec:noadd-indent-rules}),
 these comment-marked blocks are considered \texttt{environments}.

\subsubsection{lookForAlignDelims: the dontMeasure feature}\label{sec:dontMeasure}
 The \announce{2020-03-21}{don't measure feature} \texttt{lookForAlignDelims} field can,
 optionally, receive the \texttt{dontMeasure} option which can be specified in a few
 different ways. We will explore this feature in relation to the code given in
 \cref{lst:tabular-DM}; the default output is shown in \cref{lst:tabular-DM-default}.
 \index{delimiters!dontMeasure feature}%

 \begin{cmhtcbraster}[raster left skip=-1.5cm,]
  \cmhlistingsfromfile{demonstrations/tabular-DM.tex}{\texttt{tabular-DM.tex}}{lst:tabular-DM}
  \cmhlistingsfromfile{demonstrations/tabular-DM-default.tex}{\texttt{tabular-DM.tex} default output}{lst:tabular-DM-default}
 \end{cmhtcbraster}

 The \texttt{dontMeasure} field can be specified as \texttt{largest}, and in which case,
 the largest element will not be measured; with reference to the YAML file given in
 \cref{lst:dontMeasure1}, we can run the command \index{switches!-l demonstration}
 \begin{commandshell} 
latexindent.pl tabular-DM.tex -l=dontMeasure1.yaml
\end{commandshell}
 and receive the output given in \cref{lst:tabular-DM-mod1}.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabular-DM-mod1.tex}{\texttt{tabular-DM.tex} using \cref{lst:dontMeasure1}}{lst:tabular-DM-mod1}
  \cmhlistingsfromfile{demonstrations/dontMeasure1.yaml}[yaml-TCB]{\texttt{dontMeasure1.yaml}}{lst:dontMeasure1}
 \end{cmhtcbraster}

 We note that the \emph{largest} column entries have not contributed to the measuring
 routine.

 The \texttt{dontMeasure} field can also be specified in the form demonstrated in
 \cref{lst:dontMeasure2}. On running the following commands, \index{switches!-l
 demonstration}
 \begin{commandshell} 
latexindent.pl tabular-DM.tex -l=dontMeasure2.yaml
\end{commandshell}
 we receive the output in \cref{lst:tabular-DM-mod2}. \index{regular
 expressions!dontMeasure feature, cell}

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabular-DM-mod2.tex}{\texttt{tabular-DM.tex} using \cref{lst:dontMeasure2} or \cref{lst:dontMeasure3}}{lst:tabular-DM-mod2}
  \cmhlistingsfromfile{demonstrations/dontMeasure2.yaml}[yaml-TCB]{\texttt{dontMeasure2.yaml}}{lst:dontMeasure2}
 \end{cmhtcbraster}

 We note that in \cref{lst:dontMeasure2} we have specified entries not to be measured, one
 entry per line.

 The \texttt{dontMeasure} field can also be specified in the forms demonstrated in
 \cref{lst:dontMeasure3} and \cref{lst:dontMeasure4}. Upon running the commands
 \index{switches!-l demonstration}
 \begin{commandshell} 
latexindent.pl tabular-DM.tex -l=dontMeasure3.yaml
latexindent.pl tabular-DM.tex -l=dontMeasure4.yaml
\end{commandshell}
 we receive the output given in \cref{lst:tabular-DM-mod3} \index{regular
 expressions!lowercase alph a-z}
 \begin{cmhtcbraster}[raster columns=3,
   raster left skip=-3.5cm,
   raster right skip=-2cm,
   raster column skip=.03\linewidth]
  \cmhlistingsfromfile{demonstrations/tabular-DM-mod3.tex}{\texttt{tabular-DM.tex} using \cref{lst:dontMeasure3} or \cref{lst:dontMeasure3}}{lst:tabular-DM-mod3}
  \cmhlistingsfromfile{demonstrations/dontMeasure3.yaml}[yaml-TCB]{\texttt{dontMeasure3.yaml}}{lst:dontMeasure3}
  \cmhlistingsfromfile{demonstrations/dontMeasure4.yaml}[yaml-TCB]{\texttt{dontMeasure4.yaml}}{lst:dontMeasure4}
 \end{cmhtcbraster}
 We note that in:
 \begin{itemize}
  \item \cref{lst:dontMeasure3} we have specified entries not to be measured, each one has a
        \emph{string} in the \texttt{this}
        field, together with an optional specification of \texttt{applyTo} as \texttt{cell};
  \item \cref{lst:dontMeasure4} we have specified entries not to be measured as a
        \emph{regular expression} using
        the \texttt{regex} field, together with an optional specification of \texttt{applyTo} as
        \texttt{cell} field, together with an optional specification of \texttt{applyTo} as
        \texttt{cell}.
 \end{itemize}
 In both cases, the default value of \texttt{applyTo} is \texttt{cell}, and does not need
 to be specified.

 We may also specify the \texttt{applyTo} field as \texttt{row}, a demonstration of which
 is given in \cref{lst:dontMeasure5}; upon running \index{switches!-l demonstration}
 \begin{commandshell} 
latexindent.pl tabular-DM.tex -l=dontMeasure5.yaml
\end{commandshell}
 we receive the output in \cref{lst:tabular-DM-mod5}.
 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabular-DM-mod5.tex}{\texttt{tabular-DM.tex} using \cref{lst:dontMeasure5}}{lst:tabular-DM-mod5}
  \cmhlistingsfromfile{demonstrations/dontMeasure5.yaml}[yaml-TCB]{\texttt{dontMeasure5.yaml}}{lst:dontMeasure5}
 \end{cmhtcbraster}

 Finally, the \texttt{applyTo} field can be specified as \texttt{row}, together with a
 \texttt{regex} expression. For example, for the settings given in
 \cref{lst:dontMeasure6}, upon running \index{switches!-l demonstration}
 \begin{commandshell} 
latexindent.pl tabular-DM.tex -l=dontMeasure6.yaml
\end{commandshell}
 we receive the output in \cref{lst:tabular-DM-mod6}. \index{regular
 expressions!dontMeasure feature, row} \index{regular expressions!lowercase alph a-z}

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabular-DM-mod6.tex}{\texttt{tabular-DM.tex} using \cref{lst:dontMeasure6}}{lst:tabular-DM-mod6}
  \cmhlistingsfromfile{demonstrations/dontMeasure6.yaml}[yaml-TCB]{\texttt{dontMeasure6.yaml}}{lst:dontMeasure6}
 \end{cmhtcbraster}

\subsubsection{lookForAlignDelims: the delimiterRegEx and delimiterJustification feature}\label{sec:delimiter-reg-ex}

 The delimiter alignment \announce{2020-03-21}{delimiterRegEx feature} will, by default,
 align code blocks at the ampersand character. The behaviour is controlled by the
 \texttt{delimiterRegEx} field within \texttt{lookForAlignDelims}; the default value is
 \lstinline*'(?<!\\)(&)'*, which can be read as: \emph{an ampersand, as long as it is not
 immediately preceeded by a backslash}. \index{warning!capturing parenthesis for
 lookForAlignDelims} \index{capturing parenthesis (regex)} \index{regular
 expressions!capturing parenthesis} \index{delimiters!delimiterRegEx}
 \index{delimiters!delimiter justification (left or right)}%

 \begin{warning}
  Important: note the `capturing' parenthesis in the \lstinline!(&)! which are necessary;
  if you intend to customise this field, then be sure to include them appropriately.
 \end{warning}

 We demonstrate how to customise this with respect to the code given in
 \cref{lst:tabbing}; the default output from \lstinline!latexindent.pl! is given in
 \cref{lst:tabbing-default}.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabbing.tex}{\texttt{tabbing.tex}}{lst:tabbing}
  \cmhlistingsfromfile{demonstrations/tabbing-default.tex}{\texttt{tabbing.tex} default output}{lst:tabbing-default}
 \end{cmhtcbraster}

 Let's say that we wish to align the code at either the \lstinline!\=! or \lstinline!\>!.
 We employ the settings given in \cref{lst:delimiterRegEx1} and run the command
 \index{switches!-l demonstration}
 \begin{commandshell}
latexindent.pl tabbing.tex -l=delimiterRegEx1.yaml
\end{commandshell}
 to receive the output given in \cref{lst:tabbing-mod1}. \index{regular
 expressions!delimiter regex at \textbackslash= or \textbackslash>}

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabbing-mod1.tex}{\texttt{tabbing.tex} using \cref{lst:delimiterRegEx1}}{lst:tabbing-mod1}
  \cmhlistingsfromfile{demonstrations/delimiterRegEx1.yaml}[yaml-TCB]{\texttt{delimiterRegEx1.yaml}}{lst:delimiterRegEx1}
 \end{cmhtcbraster}
 We note that:
 \begin{itemize}
  \item in \cref{lst:tabbing-mod1} the code has been aligned, as intended, at both the
        \lstinline!\=! and \lstinline!\>!;
  \item in \cref{lst:delimiterRegEx1} we have heeded the warning and captured the expression
        using grouping parenthesis, specified a backslash using \lstinline!\\! and said that it
        must be followed by either \lstinline!=! or \lstinline!>!.
 \end{itemize}
 We can explore \texttt{delimiterRegEx} a little further using the settings in
 \cref{lst:delimiterRegEx2} and run the command \index{switches!-l demonstration}
 \begin{commandshell}
latexindent.pl tabbing.tex -l=delimiterRegEx2.yaml
\end{commandshell}
 to receive the output given in \cref{lst:tabbing-mod2}. \index{regular
 expressions!delimiter regex at only \textbackslash>}

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabbing-mod2.tex}{\texttt{tabbing.tex} using \cref{lst:delimiterRegEx2}}{lst:tabbing-mod2}
  \cmhlistingsfromfile{demonstrations/delimiterRegEx2.yaml}[yaml-TCB]{\texttt{delimiterRegEx2.yaml}}{lst:delimiterRegEx2}
 \end{cmhtcbraster}
 We note that only the \lstinline!\>! have been aligned.

 Of course, the other lookForAlignDelims options can be used alongside the
 \texttt{delimiterRegEx}; regardless of the type of delimiter being used (ampersand or
 anything else), the fields from \vref{lst:aligndelims:advanced} remain the same; for
 example, using the settings in \cref{lst:delimiterRegEx3}, and running \index{switches!-l
 demonstration}
 \begin{commandshell}
latexindent.pl tabbing.tex -l=delimiterRegEx3.yaml
\end{commandshell}
 to receive the output given in \cref{lst:tabbing-mod3}.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabbing-mod3.tex}{\texttt{tabbing.tex} using \cref{lst:delimiterRegEx3}}{lst:tabbing-mod3}
  \cmhlistingsfromfile{demonstrations/delimiterRegEx3.yaml}[yaml-TCB]{\texttt{delimiterRegEx3.yaml}}{lst:delimiterRegEx3}
 \end{cmhtcbraster}

 It is possible that delimiters specified within \texttt{delimiterRegEx} can be of
 different lengths. Consider the file in \cref{lst:tabbing1}, and associated YAML in
 \cref{lst:delimiterRegEx4}. Note that the \cref{lst:delimiterRegEx4} specifies the option
 for the delimiter to be either \lstinline!#! or \lstinline!\>!, \emph{which are different
 lengths}. Upon running the command \index{switches!-l demonstration} \index{switches!-o
 demonstration}
 \begin{commandshell}
latexindent.pl tabbing1.tex -l=delimiterRegEx4.yaml -o=+-mod4
\end{commandshell}
 we receive the output in \cref{lst:tabbing1-mod4}. \index{regular expressions!delimiter
 regex at \#}

 \begin{cmhtcbraster}[raster columns=3,
   raster left skip=-3.5cm,
   raster right skip=-2cm,
   raster column skip=.03\linewidth]
  \cmhlistingsfromfile{demonstrations/tabbing1.tex}{\texttt{tabbing1.tex}}{lst:tabbing1}
  \cmhlistingsfromfile{demonstrations/tabbing1-mod4.tex}{\texttt{tabbing1-mod4.tex}}{lst:tabbing1-mod4}
  \cmhlistingsfromfile{demonstrations/delimiterRegEx4.yaml}[yaml-TCB]{\texttt{delimiterRegEx4.yaml}}{lst:delimiterRegEx4}
 \end{cmhtcbraster}

 You can set the \emph{delimiter} justification as either \texttt{left} (default) or
 \texttt{right}, which will only have effect when delimiters in the same column have
 different lengths. Using the settings in \cref{lst:delimiterRegEx5} and running the
 command \index{switches!-l demonstration} \index{switches!-o demonstration}
 \begin{commandshell}
latexindent.pl tabbing1.tex -l=delimiterRegEx5.yaml -o=+-mod5
\end{commandshell}
 gives the output in \cref{lst:tabbing1-mod5}. \index{regular expressions!delimiter regex
 at \# or \textbackslash>}

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabbing1-mod5.tex}{\texttt{tabbing1-mod5.tex}}{lst:tabbing1-mod5}
  \cmhlistingsfromfile{demonstrations/delimiterRegEx5.yaml}[yaml-TCB]{\texttt{delimiterRegEx5.yaml}}{lst:delimiterRegEx5}
 \end{cmhtcbraster}

 Note that in \cref{lst:tabbing1-mod5} the second set of delimiters have been \emph{right
 aligned} -- it is quite subtle!

\subsubsection{lookForAlignDelims: lookForChildCodeBlocks}\label{sec:lookForChildCodeBlocks}
 There \announce{2021-12-13}{lookForChildCodeBlocks demonstration} may be scenarios in
 which you would prefer to instruct \texttt{latexindent.pl} \emph{not} to search for child
 blocks; in which case setting \texttt{lookForChildCodeBlocks} to 0 may be a good way to
 proceed.

 Using the settings from \vref{lst:dontMeasure1} on the file in \cref{lst:tabular-DM-1}
 and running the command
 \begin{commandshell}
latexindent.pl tabular-DM-1.tex -l=dontMeasure1.yaml -o=+-mod1
\end{commandshell}
 gives the output in \cref{lst:tabular-DM-1-mod1}.
 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabular-DM-1.tex}{\texttt{tabular-DM-1.tex}}{lst:tabular-DM-1}
  \cmhlistingsfromfile{demonstrations/tabular-DM-1-mod1.tex}{\texttt{tabular-DM-1-mod1.tex}}{lst:tabular-DM-1-mod1}
 \end{cmhtcbraster}

 We can improve the output from \cref{lst:tabular-DM-1-mod1} by employing the settings in
 \cref{lst:dontMeasure1a}
 \begin{commandshell}
latexindent.pl tabular-DM-1.tex -l=dontMeasure1a.yaml -o=+-mod1a
\end{commandshell}
 which gives the output in \cref{lst:dontMeasure1a}.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/tabular-DM-1-mod1a.tex}{\texttt{tabular-DM-1-mod1a.tex}}{lst:tabular-DM-1-mod1a}
  \cmhlistingsfromfile{demonstrations/dontMeasure1a.yaml}[yaml-TCB]{\texttt{dontMeasure1a.yaml}}{lst:dontMeasure1a}
 \end{cmhtcbraster}

\subsection{Indent after items, specials and headings}
\yamltitle{indentAfterItems}*{fields}
 The environment names specified in \texttt{indentAfterItems} tell \texttt{latexindent.pl}
 to look for \lstinline!\item! commands; if these switches are set to \texttt{1} then
 indentation will be performed so as indent the code after each \texttt{item}. A
 demonstration is given in \cref{lst:itemsbefore,lst:itemsafter}

 \begin{cmhtcbraster}[raster columns=3,
   raster left skip=-3.5cm,
   raster right skip=-2cm,
   raster column skip=.03\linewidth]
  \cmhlistingsfromfile[style=indentAfterItems]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{indentAfterItems}}{lst:indentafteritems}
  \cmhlistingsfromfile{demonstrations/items1.tex}{\texttt{items1.tex}}{lst:itemsbefore}
  \cmhlistingsfromfile{demonstrations/items1-default.tex}{\texttt{items1.tex} default output}{lst:itemsafter}
 \end{cmhtcbraster}

\yamltitle{itemNames}*{fields}
 If you have your own \texttt{item} commands (perhaps you prefer to use \texttt{myitem},
 for example) then you can put populate them in \texttt{itemNames}. For example, users of
 the \texttt{exam} document class might like to add \texttt{parts} to
 \texttt{indentAfterItems} and \texttt{part} to \texttt{itemNames} to their user settings
 (see \vref{sec:indentconfig} for details of how to configure user settings, and
 \vref{lst:mysettings} \\ in particular \label{page:examsettings}.)

 \cmhlistingsfromfile[style=itemNames]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{itemNames}}{lst:itemNames}

\yamltitle{specialBeginEnd}*{fields}\label{yaml:specialBeginEnd}
 The fields specified \index{specialBeginEnd!introduction}
 \announce{2017-08-21}*{specialBeginEnd} in \texttt{specialBeginEnd} are, in their default
 state, focused on math mode begin and end statements, but there is no requirement for
 this to be the case; \cref{lst:specialBeginEnd} shows the default settings of
 \texttt{specialBeginEnd}. \index{specialBeginEnd!default settings}%

 \cmhlistingsfromfile[style=specialBeginEnd]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{specialBeginEnd}}{lst:specialBeginEnd}

 The field \texttt{displayMath} represents \lstinline!\[...\]!, \texttt{inlineMath}
 represents \lstinline!$...$! and \texttt{displayMathTex} represents \lstinline!$$...$$!.
 You can, of course, rename these in your own YAML files (see \vref{sec:localsettings});
 indeed, you might like to set up your own special begin and end statements.

 A demonstration of the before-and-after results are shown in
 \cref{lst:specialbefore,lst:specialafter}.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/special1.tex}{\texttt{special1.tex} before}{lst:specialbefore}
  \cmhlistingsfromfile{demonstrations/special1-default.tex}{\texttt{special1.tex} default output}{lst:specialafter}
 \end{cmhtcbraster}

 For each field, \texttt{lookForThis} is set to \texttt{1} by default, which means that
 \texttt{latexindent.pl} will look for this pattern; you can tell \texttt{latexindent.pl}
 not to look for the pattern, by setting \texttt{lookForThis} to \texttt{0}.

 There are \announce{2017-08-21}{specialBeforeCommand} examples in which it is
 advantageous to search for \texttt{specialBeginEnd} fields \emph{before} searching for
 commands, and the \texttt{specialBeforeCommand} switch controls this behaviour. For
 example, consider the file shown in \cref{lst:specialLRbefore}.%

 \cmhlistingsfromfile{demonstrations/specialLR.tex}{\texttt{specialLR.tex}}{lst:specialLRbefore}

 Now consider the YAML files shown in
 \cref{lst:specialsLeftRight-yaml,lst:specialBeforeCommand-yaml}
 \index{specialBeginEnd!searching for special before commands}

 \begin{cmhtcbraster}
  \cmhlistingsfromfile[]{demonstrations/specialsLeftRight.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{specialsLeftRight.yaml}}{lst:specialsLeftRight-yaml}
  \cmhlistingsfromfile[]{demonstrations/specialBeforeCommand.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{specialBeforeCommand.yaml}}{lst:specialBeforeCommand-yaml}
 \end{cmhtcbraster}

 Upon running the following commands \index{switches!-l demonstration}
 \begin{widepage}
  \begin{commandshell}
latexindent.pl specialLR.tex -l=specialsLeftRight.yaml      
latexindent.pl specialLR.tex -l=specialsLeftRight.yaml,specialBeforeCommand.yaml      
\end{commandshell}
 \end{widepage}
 we receive the respective outputs in
 \cref{lst:specialLR-comm-first-tex,lst:specialLR-special-first-tex}.

 \begin{minipage}{.49\linewidth}
  \cmhlistingsfromfile{demonstrations/specialLR-comm-first.tex}{\texttt{specialLR.tex} using \cref{lst:specialsLeftRight-yaml}}{lst:specialLR-comm-first-tex}
 \end{minipage}
 \hfill
 \begin{minipage}{.49\linewidth}
  \cmhlistingsfromfile{demonstrations/specialLR-special-first.tex}{\texttt{specialLR.tex} using \cref{lst:specialsLeftRight-yaml,lst:specialBeforeCommand-yaml}}{lst:specialLR-special-first-tex}
 \end{minipage}

 Notice that in:
 \begin{itemize}
  \item \cref{lst:specialLR-comm-first-tex} the \lstinline!\left! has been treated as a
        \emph{command}, with one optional argument;
  \item \cref{lst:specialLR-special-first-tex} the \texttt{specialBeginEnd} pattern in
        \cref{lst:specialsLeftRight-yaml}
        has been obeyed because \cref{lst:specialBeforeCommand-yaml} specifies that the
        \texttt{specialBeginEnd} should be sought \emph{before} commands.
 \end{itemize}

 You can,optionally, specify \announce{2018-04-27}{update to specialBeginEnd} the
 \texttt{middle} field for anything that you specify in \texttt{specialBeginEnd}. For
 example, let's consider the \texttt{.tex} file in \cref{lst:special2}.
 \index{specialBeginEnd!middle} \index{specialBeginEnd!IfElsFi example}%

 \cmhlistingsfromfile{demonstrations/special2.tex}{\texttt{special2.tex}}{lst:special2}

 Upon saving the YAML settings in \cref{lst:middle-yaml,lst:middle1-yaml} and running the
 commands \index{switches!-l demonstration}
 \begin{commandshell}
latexindent.pl special2.tex -l=middle
latexindent.pl special2.tex -l=middle1
\end{commandshell}
 then we obtain the output given in \cref{lst:special2-mod1,lst:special2-mod2}.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/middle.yaml}[yaml-TCB]{\texttt{middle.yaml}}{lst:middle-yaml}
  \cmhlistingsfromfile{demonstrations/special2-mod1.tex}{\texttt{special2.tex} using \cref{lst:middle-yaml}}{lst:special2-mod1}
 \end{cmhtcbraster}

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/middle1.yaml}[yaml-TCB]{\texttt{middle1.yaml}}{lst:middle1-yaml}
  \cmhlistingsfromfile{demonstrations/special2-mod2.tex}{\texttt{special2.tex} using \cref{lst:middle1-yaml}}{lst:special2-mod2}
 \end{cmhtcbraster}

 We note that:
 \begin{itemize}
  \item in \cref{lst:special2-mod1} the bodies of each of the \texttt{Elsif} statements have been
        indented appropriately;
  \item the \texttt{Else} statement has \emph{not} been indented appropriately in
        \cref{lst:special2-mod1} -- read on!
  \item we have specified multiple settings for the \texttt{middle} field using the syntax
        demonstrated in \cref{lst:middle1-yaml} so that the body of the \texttt{Else} statement
        has been indented appropriately in \cref{lst:special2-mod2}.
 \end{itemize}

 You may \announce{2018-08-13}{specialBeginEnd verbatim} specify fields in
 \texttt{specialBeginEnd} to be treated as verbatim code blocks by changing
 \texttt{lookForThis} to be \texttt{verbatim}. \index{verbatim!specialBeginEnd}%

 For example, beginning with the code in \cref{lst:special3-mod1} and the YAML in
 \cref{lst:special-verb1-yaml}, and running \index{switches!-l demonstration}
 \begin{commandshell}
latexindent.pl special3.tex -l=special-verb1
\end{commandshell}
 then the output in \cref{lst:special3-mod1} is unchanged.
 \index{specialBeginEnd!specifying as verbatim}

 \begin{cmhtcbraster}
  \cmhlistingsfromfile{demonstrations/special-verb1.yaml}[yaml-TCB]{\texttt{special-verb1.yaml}}{lst:special-verb1-yaml}
  \cmhlistingsfromfile{demonstrations/special3-mod1.tex}{\texttt{special3.tex} and output using \cref{lst:special-verb1-yaml}}{lst:special3-mod1}
 \end{cmhtcbraster}

 We can combine the \texttt{specialBeginEnd} with the \texttt{lookForAlignDelims} feature.
 We begin with the code in \cref{lst:special-align}.

 \cmhlistingsfromfile{demonstrations/special-align.tex}{\texttt{special-align.tex}}{lst:special-align}

 Let's assume that our goal is to align the code at the \texttt{edge} and \texttt{node}
 text; we employ the code given in \cref{lst:edge-node1} and run the command
 \index{switches!-l demonstration} \index{switches!-o demonstration}
 \begin{commandshell}
latexindent.pl special-align.tex -l edge-node1.yaml -o=+-mod1
\end{commandshell}
 to receive the output in \cref{lst:special-align-mod1}. \index{specialBeginEnd!combined
 with lookForAlignDelims} \index{specialBeginEnd!delimiterRegEx}
 \index{specialBeginEnd!alignment at delimiter} \index{specialBeginEnd!tikz example}
 \index{regular expressions!delimiter alignment for edge or node} \index{delimiters!within
 specialBeginEnd blocks} \index{regular expressions!numeric 0-9}

 \begin{cmhtcbraster}[ raster left skip=-3.5cm,]
  \cmhlistingsfromfile{demonstrations/edge-node1.yaml}[yaml-TCB]{\texttt{edge-node1.yaml}}{lst:edge-node1}
  \cmhlistingsfromfile{demonstrations/special-align-mod1.tex}{\texttt{special-align.tex} using \cref{lst:edge-node1}}{lst:special-align-mod1}
 \end{cmhtcbraster}

 The output in \cref{lst:special-align-mod1} is not quite ideal. We can tweak the settings
 within \cref{lst:edge-node1} in order to improve the output; in particular, we employ the
 code in \cref{lst:edge-node2} and run the command \index{switches!-l demonstration}
 \index{switches!-o demonstration} \index{regular expressions!uppercase alph A-Z}
 \begin{commandshell}
latexindent.pl special-align.tex -l edge-node2.yaml -o=+-mod2
\end{commandshell}
 to receive the output in \cref{lst:special-align-mod2}.
 \index{specialBeginEnd!delimiterRegEx tweaked} \index{regular expressions!at least one +}
 \index{regular expressions!horizontal space \textbackslash{h}}

 \begin{cmhtcbraster}[ raster left skip=-3.5cm,]
  \cmhlistingsfromfile{demonstrations/edge-node2.yaml}[yaml-TCB]{\texttt{edge-node2.yaml}}{lst:edge-node2}
  \cmhlistingsfromfile{demonstrations/special-align-mod2.tex}{\texttt{special-align.tex} using \cref{lst:edge-node2}}{lst:special-align-mod2}
 \end{cmhtcbraster}

 The \texttt{lookForThis} field can be considered optional;
 \announce{2021-06-19}*{lookForThis optional for specialBeginEnd} by default, it is
 assumed to be 1, which is demonstrated in \cref{lst:edge-node2}.%

\yamltitle{indentAfterHeadings}*{fields}
 This field enables the user to specify indentation rules that take effect after heading
 commands such as \lstinline!\part!, \lstinline!\chapter!, \lstinline!\section!,
 \lstinline!\subsection*!, or indeed any user-specified command written in this
 field.\footnote{There is a slight difference in interface for this field when comparing
 Version 2.2 to Version 3.0; see \vref{app:differences} for details.}

 \cmhlistingsfromfile[style=indentAfterHeadings]{../defaultSettings.yaml}[width=.8\linewidth,before=\centering,yaml-TCB]{\texttt{indentAfterHeadings}}{lst:indentAfterHeadings}

 The default settings do \emph{not} place indentation after a heading, but you can easily
 switch them on by changing \texttt{indentAfterThisHeading} from 0 to 1. The
 \texttt{level} field tells \texttt{latexindent.pl} the hierarchy of the heading structure
 in your document. You might, for example, like to have both \texttt{section} and
 \texttt{subsection} set with \texttt{level: 3} because you do not want the indentation to
 go too deep.

 You can add any of your own custom heading commands to this field, specifying the
 \texttt{level} as appropriate. You can also specify your own indentation in
 \texttt{indentRules} (see \vref{sec:noadd-indent-rules}); you will find the default
 \texttt{indentRules} contains \lstinline!chapter: " "! which tells
 \texttt{latexindent.pl} simply to use a space character after \texttt{chapter} headings
 (once \texttt{indent} is set to \texttt{1} for \texttt{chapter}).

 For example, assuming that you have the code in \cref{lst:headings1yaml} saved into
 \texttt{headings1.yaml}, and that you have the text from \cref{lst:headings1} saved into
 \texttt{headings1.tex}.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile[style=yaml-LST]{demonstrations/headings1.yaml}[yaml-TCB]{\texttt{headings1.yaml}}{lst:headings1yaml}
  \cmhlistingsfromfile{demonstrations/headings1.tex}{\texttt{headings1.tex}}{lst:headings1}
 \end{cmhtcbraster}

 If you run the command \index{switches!-l demonstration}
 \begin{commandshell}
latexindent.pl headings1.tex -l=headings1.yaml
\end{commandshell}
 then you should receive the output given in \cref{lst:headings1-mod1}.

 \begin{minipage}{.45\textwidth}
  \cmhlistingsfromfile[showtabs=true]{demonstrations/headings1-mod1.tex}{\texttt{headings1.tex} using \cref{lst:headings1yaml}}{lst:headings1-mod1}
 \end{minipage}%
 \hfill
 \begin{minipage}{.45\textwidth}
  \cmhlistingsfromfile[showtabs=true]{demonstrations/headings1-mod2.tex}{\texttt{headings1.tex} second modification}{lst:headings1-mod2}
 \end{minipage}

 Now say that you modify the \texttt{YAML} from \cref{lst:headings1yaml} so that the
 \texttt{paragraph} \texttt{level} is \texttt{1}; after running \index{switches!-l
 demonstration}
 \begin{commandshell}
latexindent.pl headings1.tex -l=headings1.yaml
\end{commandshell}
 you should receive the code given in \cref{lst:headings1-mod2}; notice that the
 \texttt{paragraph} and \texttt{subsection} are at the same indentation level.

 \index{indentation!maximum indetation}

\yamltitle{maximumIndentation}*{horizontal space}
 You can control the maximum indentation given to your file by
 \announce{2017-08-21}{maximumIndentation} specifying the \texttt{maximumIndentation}
 field as horizontal space (but \emph{not} including tabs). This feature uses the
 \texttt{Text::Tabs} module \cite{texttabs}, and is \emph{off} by default.%

 For example, consider the example shown in \cref{lst:mult-nested} together with the
 default output shown in \cref{lst:mult-nested-default}.

 \begin{cmhtcbraster}[raster column skip=.1\linewidth]
  \cmhlistingsfromfile{demonstrations/mult-nested.tex}{\texttt{mult-nested.tex}}{lst:mult-nested}
  \cmhlistingsfromfile[showtabs=true]{demonstrations/mult-nested-default.tex}{\texttt{mult-nested.tex} default output}{lst:mult-nested-default}
 \end{cmhtcbraster}

 Now say that, for example, you have the \texttt{max-indentation1.yaml} from
 \cref{lst:max-indentation1yaml} and that you run the following command:
 \index{switches!-l demonstration}
 \begin{commandshell}
latexindent.pl mult-nested.tex -l=max-indentation1
\end{commandshell}
 You should receive the output shown in \cref{lst:mult-nested-max-ind1}.

 \begin{cmhtcbraster}
  \cmhlistingsfromfile[style=yaml-LST]{demonstrations/max-indentation1.yaml}[yaml-TCB]{\texttt{max-indentation1.yaml}}{lst:max-indentation1yaml}
  \cmhlistingsfromfile[showspaces=true]{demonstrations/mult-nested-max-ind1.tex}{\texttt{mult-nested.tex} using \cref{lst:max-indentation1yaml}}{lst:mult-nested-max-ind1}
 \end{cmhtcbraster}

 Comparing the output in \cref{lst:mult-nested-default,lst:mult-nested-max-ind1} we notice
 that the (default) tabs of indentation have been replaced by a single space.

 In general, when using the \texttt{maximumIndentation} feature, any leading tabs will be
 replaced by equivalent spaces except, of course, those found in
 \texttt{verbatimEnvironments} (see \vref{lst:verbatimEnvironments}) or
 \texttt{noIndentBlock} (see \vref{lst:noIndentBlock}).

\subsection{The code blocks known latexindent.pl}\label{subsubsec:code-blocks}

 As of Version 3.0, \texttt{latexindent.pl} processes documents using code blocks; each of
 these are shown in \cref{tab:code-blocks}. \index{regular expressions!uppercase alph A-Z}
 \index{regular expressions!lowercase alph a-z} \index{regular expressions!numeric 0-9}
 \index{regular expressions!horizontal space \textbackslash{h}}

 \begin{table}[!htp]
  \begin{widepage}
   \centering
   \caption{Code blocks known to \texttt{latexindent.pl}}
   \label{tab:code-blocks}
   \begin{tabular}{m{.3\linewidth}@{\hspace{.25cm}}m{.4\linewidth}@{\hspace{.25cm}}m{.2\linewidth}}
    \toprule
    Code block                    & characters allowed in name                                                                  & example                                                                                                                                                                \\
    \midrule
    environments                  & \lstinline!a-zA-Z@\*0-9_\\!                                                                 &
    \begin{lstlisting}[,nolol=true,]
\begin{myenv}
body of myenv
\end{myenv}
  \end{lstlisting}
    \\\cmidrule{2-3}
    optionalArguments             & \emph{inherits} name from parent (e.g environment name)                                     &
    \begin{lstlisting}[,nolol=true,]
[
opt arg text
]
  \end{lstlisting}
    \\\cmidrule{2-3}
    mandatoryArguments            & \emph{inherits} name from parent (e.g environment name)                                     &
    \begin{lstlisting}[,nolol=true,]
{
mand arg text
}
  \end{lstlisting}
    \\\cmidrule{2-3}
    commands                      & \lstinline!+a-zA-Z@\*0-9_\:!                                                                & \lstinline!\mycommand!$\langle$\itshape{arguments}$\rangle$                                                                                                            \\\cmidrule{2-3}
    keyEqualsValuesBracesBrackets & \lstinline!a-zA-Z@\*0-9_\/.\h\{\}:\#-!                                                      & \lstinline!my key/.style=!$\langle$\itshape{arguments}$\rangle$                                                                                                        \\\cmidrule{2-3}
    namedGroupingBracesBrackets   & \lstinline!0-9\.a-zA-Z@\*><!                                                                & \lstinline!in!$\langle$\itshape{arguments}$\rangle$                                                                                                                    \\\cmidrule{2-3}
    UnNamedGroupingBracesBrackets & \centering\emph{No name!}                                                                   & \lstinline!{! or \lstinline![! or \lstinline!,! or \lstinline!\&! or \lstinline!)! or \lstinline!(! or \lstinline!$! followed by $\langle$\itshape{arguments}$\rangle$ \\\cmidrule{2-3}
    ifElseFi                      & \lstinline!@a-zA-Z! but must begin with either \newline \lstinline!\if! of \lstinline!\@if! &
    \begin{lstlisting}[,nolol=true,]
\ifnum...
...
\else
...
\fi
  \end{lstlisting}                                                                                                                                                                                                                                                                      \\\cmidrule{2-3}
    items                         & User specified, see \vref{lst:indentafteritems,lst:itemNames}                               &
    \begin{lstlisting}[,nolol=true,]
\begin{enumerate}
  \item ...
\end{enumerate}
  \end{lstlisting}                                                                                                                                                                                                                                                                      \\\cmidrule{2-3}
    specialBeginEnd               & User specified, see \vref{lst:specialBeginEnd}                                              &
    \begin{lstlisting}[,nolol=true,]
\[
  ...
\]
  \end{lstlisting}                                                                                                                                                                                                                                                                      \\\cmidrule{2-3}
    afterHeading                  & User specified, see \vref{lst:indentAfterHeadings}                                          &
    \begin{lstlisting}[,morekeywords={chapter},nolol=true,]
\chapter{title}
  ...
\section{title}
  \end{lstlisting}                                                                                                                                                                                                                                               \\\cmidrule{2-3}
    filecontents                  & User specified, see \vref{lst:fileContentsEnvironments}                                     &
    \begin{lstlisting}[,nolol=true,]
\begin{filecontents}
...
\end{filecontents}
  \end{lstlisting}                                                                                                                                                                                                                                                                      \\
    \bottomrule
   \end{tabular}
  \end{widepage}
 \end{table}

 We will refer to these code blocks in what follows. \announce{2019-07-13}{fine tuning of
 code blocks} Note that the fine tuning of the definition of the code blocks detailed in
 \cref{tab:code-blocks} is discussed in \vref{sec:finetuning}.%