CTAN sync 202005300301

5 files changed, 1847 insertions, 1780 deletions

diff --git a/macros/luatex/generic/nodetree/README.md b/macros/luatex/generic/nodetree/README.md
index 2b92a67fa2..7f21098f11 100644
--- a/macros/luatex/generic/nodetree/README.md
+++ b/macros/luatex/generic/nodetree/README.md
@@ -1,4 +1,3 @@
-
 ![nodetree](https://raw.githubusercontent.com/Josef-Friedrich/nodetree/master/graphics/packagename.png)
 
 # Abstract
@@ -19,7 +18,7 @@ terminal to generate the document.
 
 # License
 
-Copyright (C) 2016 by Josef Friedrich <josef@friedrich.rocks>
+Copyright (C) 2016-2020 by Josef Friedrich <josef@friedrich.rocks>
 ------------------------------------------------------------------------
 This work may be distributed and/or modified under the conditions of
 the LaTeX Project Public License, either version 1.3 of this license
@@ -102,3 +101,63 @@ Office
 
 ![nodetree](https://raw.githubusercontent.com/Josef-Friedrich/nodetree/master/graphics/ligatures.png)
 
+# Development
+
+First delete the stable version installed by TeX Live. Because the
+package `nodetree` belongs to the collection `collection-latexextra`, the
+option  `--force` must be used to delete the package.
+
+    tlmgr remove --force nodetree
+
+## Deploying a new version
+
+Update the version number in the file `nodetree.dtx` on this locations:
+
+### In the markup for the file `nodetree.sty` (approximately at the line number 30)
+
+    %<*package>
+    [2016/07/18 v1.2 Visualize node lists in a tree view]
+    %<*package>
+
+### In the markup for the file `nodetree-embed.sty` (approximately at the line number 220)
+
+    %<*package>
+    [2016/07/18 v1.2 Visualize node lists in a tree view]
+    %<*package>
+
+### In the markup for the package documentation (approximately at the line number 50)
+
+Add a changes entry:
+
+```latex
+\changes{v1.2}{2020/05/20}{...}
+```
+
+### In documentation (documentation.tex) (approximately at the line number 70)
+
+```latex
+\date{v2.0 from 2020/05/29}
+```
+
+### In the file `nodetree.lua` (approximately at the line number 20)
+
+```lua
+if not modules then modules = { } end modules ['nodetree'] = {
+  version   = '1.2'
+}
+```
+
+### Update the copyright year:
+
+```
+sed -i 's/(C) 2016-2020/(C) 2016-2021/g' nodetree.ins
+sed -i 's/(C) 2016-2020/(C) 2016-2021/g' nodetree.dtx
+```
+
+### Command line tasks:
+
+```
+git tag -a v1.4
+make
+make ctan
+```
diff --git a/macros/luatex/generic/nodetree/nodetree.dtx b/macros/luatex/generic/nodetree/nodetree.dtx
index 24416e17ce..5b18176843 100644
--- a/macros/luatex/generic/nodetree/nodetree.dtx
+++ b/macros/luatex/generic/nodetree/nodetree.dtx
@@ -1,6 +1,6 @@
 % \iffalse meta-comment
 %
-% Copyright (C) 2016 by Josef Friedrich <josef@friedrich.rocks>
+% Copyright (C) 2016-2020 by Josef Friedrich <josef@friedrich.rocks>
 % ----------------------------------------------------------------------
 % This work may be distributed and/or modified under the conditions of
 % the LaTeX Project Public License, either version 1.3 of this license
@@ -28,648 +28,8 @@
 %<package>\NeedsTeXFormat{LaTeX2e}[1999/12/01]
 %<package>\ProvidesPackage{nodetree}
 %<*package>
-    [2016/07/18 v1.2 Visualize node lists in a tree view]
+    [2020/05/29 v2.0 Visualize node lists in a tree view]
 %</package>
-%<*driver>
-\documentclass{ltxdoc}
-\usepackage{paralist,fontspec,graphicx,fancyvrb}
-\usepackage[
-  colorlinks=true,
-  linkcolor=red,
-  filecolor=red,
-  urlcolor=red,
-]{hyperref}
-%\usepackage{nodetree}
-\EnableCrossrefs
-\CodelineIndex
-\RecordChanges
-
-\setmonofont{DejaVu Sans Mono}
-
-\def\nodetreelua#1{\texttt{\scantokens{\catcode`\_=12\relax#1}}}
-
-\def\secref#1{(\rightarrow\ \ref{#1})}
-
-\newcommand{\tmpgraphics}[1]{
-  \noindent
-  \includegraphics[scale=0.4]{graphics/#1}
-}
-
-\DefineVerbatimEnvironment{code}{Verbatim}
-{
-  frame=single,
-  fontsize=\footnotesize,
-}
-
-\begin{document}
-
-\providecommand*{\url}{\texttt}
-\GetFileInfo{nodetree.dtx}
-\title{The \textsf{nodetree} package}
-\author{%
-  Josef Friedrich\\%
-  \url{josef@friedrich.rocks}\\%
-  \href{https://github.com/Josef-Friedrich/nodetree}{github.com/Josef-Friedrich/nodetree}%
-}
-\date{\fileversion~from \filedate}
-
-\maketitle
-
-\noindent
-\includegraphics[width=\linewidth]{graphics/packagename}
-
-\newpage
-
-\tableofcontents
-
-\newpage
-
-%-----------------------------------------------------------------------
-% Abstract
-%-----------------------------------------------------------------------
-
-\section{Abstract}
-
-|nodetree| is a development package that visualizes the structure of
-node lists. |nodetree| shows its debug informations in the consoles’
-output when you compile a Lua\TeX{} file. It uses a similar visual
-representation for node lists as the UNIX |tree| command uses for a
-folder structure.
-
-Node lists are the main building blocks of each document generated by
-the \TeX{} engine \emph{Lua\TeX}. The package |nodetree| doesn‘t change
-the rendered document. The tree view can only be seen when using a
-terminal to generate the document.
-
-|nodetree| is inspired by a
-\href{https://gist.github.com/pgundlach/556247}
-{gist from Patrick Gundlach}.
-
-%-----------------------------------------------------------------------
-% Usage
-%-----------------------------------------------------------------------
-
-\section{Usage}
-
-The package |nodetree| can be used both with Lua\TeX{} and Lua\LaTeX{}.
-You have to use both engines in a text console. Run for example
-|luatex luatex-test.tex| to list the nodes using Lua\TeX{}.
-
-\begin{code}
-\input{nodetree.tex}
-\nodetreeregister{postline}
-
-Lorem ipsum dolor.
-\bye
-\end{code}
-
-Or run |lualatex lualatex-test.tex| to show a node tree using
-Lua\LaTeX{}. In Lua\LaTeX{} you can omit |\nodetreeregister{postline}|.
-|\usepackage{nodetree}| registers automatically the
-|post_linebreak_filter|. If you don’t want debug the
-|post_linebreak_filter| use |\nodetreeunregister{postline}|.
-
-\begin{code}
-\documentclass{article}
-\usepackage{nodetree}
-
-\begin{document}
-Lorem ipsum dolor.
-\end{document}
-\end{code}
-
-%%
-% inside Lua code
-%%
-
-\subsection{Debug nodes inside Lua code}
-
-Use the Lua function |nodetree.analyze(head)| to debug nodes inside your
-Lua code. The following code snippet demonstrates the usage in Lua\TeX{}.
-|head| is the current node.
-
-\begin{code}
-\input{nodetree.tex}
-
-\directlua{
-  local test = function (head)
-    nodetree.analyze(head)
-  end
-  callback.register('post_linebreak_filter', test)
-}
-
-Lorem ipsum dolor.
-\bye
-\end{code}
-
-This example illustrates how the function has to be applied in
-Lua\LaTeX{}.
-
-\begin{code}
-\documentclass{article}
-\usepackage{nodetree}
-
-\begin{document}
-
-\directlua{
-  local test = function (head)
-    nodetree.analyze(head)
-  end
-  luatexbase.add_to_callback('post_linebreak_filter', test, 'test')
-}
-
-Lorem ipsum dolor.
-\end{document}
-\end{code}
-
-%-----------------------------------------------------------------------
-% Macros
-%-----------------------------------------------------------------------
-
-\section{Macros}
-
-%%
-% \nodetreeregister
-%%
-
-\subsection{\cmd{\nodetreeregister}}
-
-\DescribeMacro{\nodetreeregister}
-\cmd{\nodetreeregister}\marg{callbacks}: The argument \marg{callbacks}
-takes a comma separated list of callback aliases as described in
-\secref{sec:option-callback}.
-
-%%
-% \nodetreeunregister
-%%
-
-\subsection{\cmd{\nodetreeunregister}}
-
-\DescribeMacro{\nodetreeunregister}
-\cmd{\nodetreeunregister}\marg{callbacks}: The argument \marg{callbacks}
-takes a comma separated list of callback aliases as described in
-\secref{sec:option-callback}.
-
-%%
-% \nodetreeoption
-%%
-
-\subsection{\cmd{\nodetreeoption}}
-
-\DescribeMacro{\nodetreeoption}
-\cmd{\nodetreeoption}\oarg{option}\marg{value}: \secref{sec:options}
-This macro sets the option \oarg{option} to the value \marg{value}.
-
-%%
-% \nodetreeset
-%%
-
-\subsection{\cmd{\nodetreeset}}
-
-\DescribeMacro{\nodetreeset}
-\cmd{\nodetreeset}\marg{kv-options}:
-This macro can only be used in Lua\LaTeX{}. \marg{kv-options} are key
-value pairs.
-
-\begin{code}
-\nodetreeset{color=no,callbacks={hpack,vpack},verbosity=2}
-\end{code}
-
-%-----------------------------------------------------------------------
-% Options
-%-----------------------------------------------------------------------
-
-\section{Options}
-\label{sec:options}
-
-%%
-% callback
-%%
-
-\subsection{Option \texttt{callback}}
-\label{sec:option-callback}
-
-The option |callback| is the most important setting of the package. You
-have to specify one alias to select the |callback|. Because of the
-underscores the callback name contains it can not set by its technical
-name (\rightarrow{} Figure \ref{fig:callback}).
-
-This macros process callback options:
-\cmd{\nodetreeregister}\marg{callbacks},
-\cmd{\nodetreeunregister}\marg{callbacks},
-\cmd{\nodetreeset}\marg{callback=<callbacks>} and
-\cmd{\usepackage}\oarg{callback=<callbacks>}\marg{nodetree}.
-
-Use commas to specify mulitple callbacks. Avoid using whitespaces:
-
-\begin{code}
-\nodetreeregister{preline,line,postline}
-\end{code}
-
-Wrap your callback aliases in curly braces for the macro |\nodetreeset|:
-
-\begin{code}
-\nodetreeset{callback={preline,line,postline}}
-\end{code}
-
-The same applies for the macro |\usepackage|:
-
-\begin{code}
-\usepackage{callback={preline,line,postline}}
-\end{code}
-
-%%
-% Tabular callbacks
-%%
-
-\newcommand{\nodetreecallback}[3]{
-  \nodetreelua{#1} & \nodetreelua{#2} & \nodetreelua{#3} \\
-}
-
-\begin{figure}
-
-\noindent
-\begin{tabular}{lll}
-\textbf{Alias (short)} & \textbf{Alias (longer)} & \textbf{Callback} \\
-\nodetreecallback{contribute}{contributefilter}{contribute_filter}
-\nodetreecallback{buildpage}{buildpagefilter}{buildpage_filter}
-\nodetreecallback{preline}{prelinebreakfilter}{pre_linebreak_filter}
-\nodetreecallback{line}{linebreakfilter}{linebreak_filter}
-\nodetreecallback{append}{appendtovlistfilter}{append_to_vlist_filter}
-\nodetreecallback{postline}{postlinebreakfilter}{post_linebreak_filter}
-\nodetreecallback{hpack}{hpackfilter}{hpack_filter}
-\nodetreecallback{vpack}{vpackfilter}{vpack_filter}
-\nodetreecallback{hpackq}{hpackquality}{hpack_quality}
-\nodetreecallback{vpackq}{vpackquality}{vpack_quality}
-\nodetreecallback{process}{processrule}{process_rule}
-\nodetreecallback{preout}{preoutputfilter}{pre_output_filter}
-\nodetreecallback{hyph}{hyphenate}{hyphenate}
-\nodetreecallback{liga}{ligaturing}{ligaturing}
-\nodetreecallback{kern}{kerning}{kerning}
-\nodetreecallback{insert}{insertlocalpar}{insert_local_par}
-\nodetreecallback{mhlist}{mlisttohlist}{mlist_to_hlist}
-\end{tabular}
-
-\caption{The callback aliases}
-\label{fig:callback}
-\end{figure}
-
-%%
-% verbosity
-%%
-
-\subsection{Option \texttt{verbosity}}
-
-Higher integer values result in a more verbose output. The default value
-for this options is |1|. At the moment only verbosity level |2| is
-implemented.
-
-%%
-% color
-%%
-
-\subsection{Option \texttt{color}}
-
-The default option for |color| is |colored|. Use any other string (for
-example |none| or |no|) to disable the colored terminal output of the
-package.
-
-\begin{code}
-\usepackage[color=no]{nodetree}
-\end{code}
-
-%%
-% unit
-%%
-
-\subsection{Option \texttt{unit}}
-
-The option |unit| sets the length unit to display all length values of
-the nodes. The default option for |unit| is |pt|. See figure
-\ref{fig:fixed-units} and \ref{fig:relative-units} for possible values.
-
-\begin{figure}
-\begin{tabular}{lp{10cm}}
-\textbf{Unit} &
-\textbf{Description} \\
-
-pt &
-Point 1/72.27 inch. The conversion to metric units, to two decimal
-places, is 1 point = 2.85 mm = 28.45 cm. \\
-
-pc &
-Pica, 12 pt \\
-
-in &
-Inch, 72.27 pt \\
-
-bp &
-Big point, 1/72 inch. This length is the definition of a point in
-PostScript and many desktop publishing systems. \\
-
-cm &
-Centimeter \\
-
-mm &
-Millimeter \\
-
-dd &
-Didot point, 1.07 pt \\
-
-cc &
-Cicero, 12 dd \\
-
-sp &
-Scaled point, 1/65536 pt \\
-\end{tabular}
-\caption{Fixed units}
-\label{fig:fixed-units}
-\end{figure}
-
-\begin{figure}
-\begin{tabular}{lp{10cm}}
-\textbf{Unit} &
-\textbf{Description} \\
-
-ex &
-x-height of the current font \\
-
-em &
-Width of the capital letter M \\
-\end{tabular}
-\caption{Relative units}
-\label{fig:relative-units}
-\end{figure}
-
-%%
-% decimalplaces
-%%
-
-\subsection{Option \texttt{decimalplaces}}
-
-The options |decimalplaces| sets the number of decimal places for some
-node fields.
-
-\begin{code}
-\nodetreeoption[decimalplaces]{4}
-\end{code}
-
-gets
-
-\begin{code}
-├─GLYPH char: "a"; width: 5pt; height: 4.3055pt;
-\end{code}
-
-If |decimalplaces| is set to |0| only integer values are shown.
-
-\begin{code}
-├─GLYPH char: "a"; width: 5pt; height: 4pt;
-\end{code}
-
-%-----------------------------------------------------------------------
-% Visual tree structure
-%-----------------------------------------------------------------------
-
-\section{Visual tree structure}
-
-%%
-% Two different connections
-%%
-
-\subsection{Two different connections}
-
-Nodes in Lua\TeX{} are connected. The |nodetree| package distinguishs
-between the |list| and |field| connections.
-
-\begin{itemize}
- \item |list|: Nodes, which are double connected by |next| and
-       |previous| fields.
- \item |field|: Connections to nodes by other fields than |next| and
-       |previous| fields, e. g. |head|, |pre|.
-\end{itemize}
-
-%%
-% Unicode characters
-%%
-
-\subsection{Unicode characters to show the tree view}
-
-\renewcommand{\arraystretch}{1.5}
-
-The package |nodetree| uses the unicode box drawing symbols. Your
-default terminal font should contain this characters to obtain the tree
-view. Eight box drawing characters are necessary.
-
-\noindent
-\begin{tabular}{lcl}
-\textbf{Code} & \textbf{Character} & \textbf{Name} \\
-U+2500 & |─| & BOX DRAWINGS LIGHT HORIZONTAL \\
-U+2502 & |│| & BOX DRAWINGS LIGHT VERTICAL \\
-U+2514 & |└| & BOX DRAWINGS LIGHT UP AND RIGHT \\
-U+251C & |├| & BOX DRAWINGS LIGHT VERTICAL AND RIGHT \\
-U+2550 & |═| & BOX DRAWINGS DOUBLE HORIZONTAL \\
-U+2551 & |║| & BOX DRAWINGS DOUBLE VERTICAL \\
-U+255A & |╚| & BOX DRAWINGS DOUBLE UP AND RIGHT \\
-U+2560 & |╠| & BOX DRAWINGS DOUBLE VERTICAL AND RIGHT \\
-\end{tabular}
-
-For |list| connections \emph{light} characters are shown.
-
-\begin{code}
-│ │
-│ ├─list1
-│ └─list2
-└─list3
-\end{code}
-
-|field| connections are visialized by \emph{Double} characters.
-
-\begin{code}
-║ ║
-║ ╠═field1
-║ ╚═field2
-╚═field3
-\end{code}
-
-%-----------------------------------------------------------------------
-% Examples
-%-----------------------------------------------------------------------
-
-\newpage
-
-\section{Examples}
-
-%%
-% packagename
-%%
-
-\subsection{The node list of the package name}
-
-\begin{code}
-\documentclass{article}
-\usepackage{nodetree}
-\begin{document}
-nodetree
-\end{document}
-\end{code}
-
-\tmpgraphics{packagename}
-
-%%
-% math
-%%
-
-\newpage
-
-\subsection{The node list of a mathematical formula}
-
-\begin{code}
-\documentclass{article}
-\usepackage[callback={mhlist}]{nodetree}
-\begin{document}
-\[\left(a\right)\left[\frac{b}{a}\right]=a\,\]
-\end{document}
-\end{code}
-
-\tmpgraphics{math}
-
-%%
-% ligatures
-%%
-
-\newpage
-
-\subsection{The node list of the word \emph{Office}}
-
-The characters \emph{ffi} are deeply nested in a discretionary node.
-
-\begin{code}
-\documentclass{article}
-\usepackage{nodetree}
-\begin{document}
-Office
-\end{document}
-\end{code}
-
-\tmpgraphics{ligatures}
-
-%-----------------------------------------------------------------------
-% Index
-%-----------------------------------------------------------------------
-
-  \DocInput{nodetree.dtx}
-  \pagebreak
-  \PrintChanges
-  \pagebreak
-  \PrintIndex
-\end{document}
-%</driver>
-%<*readme>
-
-![nodetree](https://raw.githubusercontent.com/Josef-Friedrich/nodetree/master/graphics/packagename.png)
-
-# Abstract
-
-`nodetree` is a development package that visualizes the structure of
-node lists. `nodetree` shows its debug informations in the consoles’
-output when you compile a LuaTeX file. It uses a similar visual
-representation for node lists as the UNIX `tree` command uses for a
-folder structure.
-
-Node lists are the main building blocks of each document generated by
-the TeX engine LuaTeX. The package `nodetree` doesn‘t change
-the rendered document. The tree view can only be seen when using a
-terminal to generate the document.
-
-`nodetree` is inspired by a
-[gist from Patrick Gundlach](https://gist.github.com/pgundlach/556247).
-
-# License
-
-Copyright (C) 2016 by Josef Friedrich <josef@friedrich.rocks>
-------------------------------------------------------------------------
-This work may be distributed and/or modified under the conditions of
-the LaTeX Project Public License, either version 1.3 of this license
-or (at your option) any later version.  The latest version of this
-license is in:
-
-  http://www.latex-project.org/lppl.txt
-
-and version 1.3 or later is part of all distributions of LaTeX
-version 2005/12/01 or later.
-
-# CTAN
-
-Since July 2016 the cloze package is included in the Comprehensive TeX
-Archive Network (CTAN).
-
-* TeX archive: http://mirror.ctan.org/tex-archive/macros/luatex/generic/nodetree
-* Package page: http://www.ctan.org/pkg/nodetree
-
-# Repository
-
-https://github.com/Josef-Friedrich/nodetree
-
-# Installation
-
-Get source:
-
-    git clone git@github.com:Josef-Friedrich/nodetree.git
-    cd nodetree
-
-Compile:
-
-    make
-
-or manually:
-
-    luatex nodetree.ins
-    lualatex nodetree.dtx
-    makeindex -s gglo.ist -o nodetree.gls nodetree.glo
-    makeindex -s gind.ist -o nodetree.ind nodetree.idx
-    lualatex nodetree.dtx
-
-# Examples
-
-## The node list of the package name
-
-```latex
-\documentclass{article}
-\usepackage{nodetree}
-\begin{document}
-nodetree
-\end{document}
-```
-
-![nodetree](graphics/packagename.png)
-
-## The node list of a mathematical formula
-
-```latex
-\documentclass{article}
-\usepackage[callback={mhlist}]{nodetree}
-\begin{document}
-\[\left(a\right)\left[\frac{b}{a}\right]=a\,\]
-\end{document}
-```
-
-![nodetree](https://raw.githubusercontent.com/Josef-Friedrich/nodetree/master/graphics/math.png)
-
-## The node list of the word 'Office'
-
-The characters 'ffi' are deeply nested in a discretionary node.
-
-```latex
-\documentclass{article}
-\usepackage{nodetree}
-\begin{document}
-Office
-\end{document}
-```
-
-![nodetree](https://raw.githubusercontent.com/Josef-Friedrich/nodetree/master/graphics/ligatures.png)
-
-%</readme>
 % \fi
 %
 % \CheckSum{0}
@@ -695,6 +55,16 @@ Office
 % \changes{v1.0}{2016/07/07}{Inital release}
 % \changes{v1.1}{2016/07/13}{Fix the registration of same callbacks}
 % \changes{v1.2}{2016/07/18}{Fix difference between README.md in the upload and that from nodetree.dtx}
+% \changes{v2.0}{2020/05/29}{
+%  * Switch from lowercase macro names to PascalCase names for better readability.
+%  * The Lua code is no longer developed inside the DTX file, instead in a separate file named nodetree.lua.
+%  * Add a sub package named nodetree-embed.sty for embedding nodetree views into a \LaTeX{} document.
+%  * Add support for new node subtype names.
+%  * Add support for a new Lua\TeX{} node callback.
+%  * Add support for node properties.
+%  * Less verbose representation of node attributes.
+%  * Minor tree output adjustments.
+% }
 %
 % \DoNotIndex{\newcommand,\newenvironment,\def,\directlua}
 %
@@ -716,40 +86,68 @@ Office
 %    \begin{macrocode}
 \directlua{
   nodetree = require('nodetree')
-  nodetree.set_option('engine', 'luatex')
-  nodetree.set_default_options()
 }
 %    \end{macrocode}
 %
-% \begin{macro}{\nodetreeoption}
+% \begin{macro}{\NodetreeSetOption}
 %    \begin{macrocode}
-\def\nodetreeoption[#1]#2{
+\def\NodetreeSetOption[#1]#2{
   \directlua{
     nodetree.set_option('#1', '#2')
   }
 }
+\let\nodetreeoption\NodetreeSetOption
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\NodetreeResetOption}
+%    \begin{macrocode}
+\def\NodetreeResetOption#1{
+  \NodetreeSetOption[#1]{%
+    \directlua{
+      tex.print(nodetree.get_default_option('#1'))
+    }%
+  }%
+}
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}{\nodetreeregister}
+% \begin{macro}{\NodetreeReset}
 %    \begin{macrocode}
-\def\nodetreeregister#1{
+\def\NodetreeReset{
+  \NodetreeResetOption{callback}
+  \NodetreeResetOption{channel}
+  \NodetreeResetOption{color}
+  \NodetreeResetOption{decimalplaces}
+  \NodetreeResetOption{engine}
+  \NodetreeResetOption{unit}
+  \NodetreeResetOption{verbosity}
+}
+\let\nodetreereset\NodetreeReset
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}{\NodetreeRegisterCallback}
+%    \begin{macrocode}
+\def\NodetreeRegisterCallback#1{
   \directlua{
     nodetree.set_option('callback', '#1')
     nodetree.register_callbacks()
   }
 }
+\let\nodetreeregister\NodetreeRegisterCallback
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}{\nodetreeunregister}
+% \begin{macro}{\NodetreeUnregisterCallback}
 %    \begin{macrocode}
-\def\nodetreeunregister#1{
+\def\NodetreeUnregisterCallback#1{
   \directlua{
     nodetree.set_option('callback', '#1')
     nodetree.unregister_callbacks()
   }
 }
+\let\nodetreeunregister\NodetreeUnregisterCallback
 %    \end{macrocode}
 % \end{macro}
 %
@@ -765,9 +163,6 @@ Office
 %
 %    \begin{macrocode}
 \input{nodetree}
-\directlua{
-  nodetree.set_option('engine', 'lualatex')
-}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
@@ -777,1233 +172,303 @@ Office
 %    \begin{macrocode}
 \SetupKeyvalOptions{
   family=NT,
-  prefix=NT@
+  prefix=NTK@
 }
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \DeclareStringOption[term]{channel}
-\define@key{NT}{channel}[]{\nodetreeoption[channel]{#1}}
+\define@key{NT}{channel}[]{\NodetreeSetOption[channel]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \DeclareStringOption[postlinebreak]{callback}
-\define@key{NT}{callback}[]{\nodetreeoption[callback]{#1}}
+\define@key{NT}{callback}[]{\NodetreeSetOption[callback]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \DeclareStringOption[1]{verbosity}
-\define@key{NT}{verbosity}[]{\nodetreeoption[verbosity]{#1}}
+\define@key{NT}{verbosity}[]{\NodetreeSetOption[verbosity]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \DeclareStringOption[colored]{color}
-\define@key{NT}{color}[]{\nodetreeoption[color]{#1}}
+\define@key{NT}{color}[]{\NodetreeSetOption[color]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \DeclareStringOption[1]{unit}
-\define@key{NT}{unit}[]{\nodetreeoption[unit]{#1}}
+\define@key{NT}{unit}[]{\NodetreeSetOption[unit]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
 \DeclareStringOption[1]{decimalplaces}
-\define@key{NT}{decimalplaces}[]{\nodetreeoption[decimalplaces]{#1}}
+\define@key{NT}{decimalplaces}[]{\NodetreeSetOption[decimalplaces]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-\ProcessKeyvalOptions*
+\ProcessKeyvalOptions{NT}
 \directlua{
-  nodetree.set_default_options()
   nodetree.register_callbacks()
 }
 %    \end{macrocode}
 %
-% \begin{macro}{\nodetreeset}
+% \begin{macro}{\NodetreeSet}
 %    \begin{macrocode}
-\newcommand{\nodetreeset}[1]{\setkeys{nodetree}{#1}}
+\newcommand{\NodetreeSet}[1]{%
+  \setkeys{NT}{#1}%
+}
+\let\nodetreeset\NodetreeSet
 %    \end{macrocode}
 % \end{macro}
 %
 % \iffalse
 %</package>
-%<*luamain>
+%<*packageembed>
 % \fi
-%
-% \makeatletter
-% \c@CodelineNo 0 \relax
-% \makeatother
-%
-% \subsection{The file \tt{nodetree.lua}}
-%
-%    \begin{macrocode}
-local nodex = {}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-local tpl = {}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-local tree = {}
-%    \end{macrocode}
-%
-% Nodes in Lua\TeX{} are connected. The nodetree view distinguishs
-% between the |list| and |field| connections.
-%
-% \begin{itemize}
-%  \item |list|: Nodes, which are double connected by |next| and
-%        |previous| fields.
-%  \item |field|: Connections to nodes by other fields than |next| and
-%        |previous| fields, e. g. |head|, |pre|.
-% \end{itemize}
-%
-% The lua table named |tree.state| holds state values for the current
-% tree item.
-%
-% \begin{code}
-%  tree.state:
-%    - 1:
-%      - list: continue
-%      - field: stop
-%    - 2:
-%      - list: continue
-%      - field: stop
-% \end{code}
-%    \begin{macrocode}
-tree.state = {}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-local callbacks = {}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-local base = {}
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-local options = {}
-%    \end{macrocode}
-%
-% \subsubsection{nodex --- Extend the node library}
-%
-% Get the node id form, e. g.:
-% \begin{code}
-% <node    nil <    172 >    nil : hlist 2>
-% \end{code}
-%    \begin{macrocode}
-function nodex.node_id(n)
-  return string.gsub(tostring(n), '^<node%s+%S+%s+<%s+(%d+).*', '%1')
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function nodex.subtype(n)
-  local typ = node.type(n.id)
-  local subtypes = {
-%    \end{macrocode}
-% \paragraph{hlist (0)}
-%    \begin{macrocode}
-    hlist = {
-      [0] = 'unknown',
-      [1] = 'line',
-      [2] = 'box',
-      [3] = 'indent',
-      [4] = 'alignment',
-      [5] = 'cell',
-      [6] = 'equation',
-      [7] = 'equationnumber',
-    },
-%    \end{macrocode}
-% \paragraph{vlist (1)}
-%    \begin{macrocode}
-    vlist = {
-      [0] = 'unknown',
-      [4] = 'alignment',
-      [5] = 'cell',
-    },
-%    \end{macrocode}
-% \paragraph{rule (2)}
-%    \begin{macrocode}
-    rule = {
-      [0] = 'unknown',
-      [1] = 'box',
-      [2] = 'image',
-      [3] = 'empty',
-      [4] = 'user',
-    },
-%    \end{macrocode}
-%
-% \noindent
-% Nodes without subtypes:
-% \begin{compactitem}
-% \item ins (3)
-% \item mark (4)
-% \end{compactitem}
-%    \begin{macrocode}
-%    \end{macrocode}
-% \paragraph{adjust (5)}
-%    \begin{macrocode}
-    adjust = {
-      [0] = 'normal',
-      [1] = 'pre',
-    },
-%    \end{macrocode}
-% \paragraph{boundary (6)}
-%    \begin{macrocode}
-    boundary = {
-      [0] = 'cancel',
-      [1] = 'user',
-      [2] = 'protrusion',
-      [3] = 'word',
-    },
-%    \end{macrocode}
-% \paragraph{disc (7)}
-%    \begin{macrocode}
-    disc  = {
-      [0] = 'discretionary',
-      [1] = 'explicit',
-      [2] = 'automatic',
-      [3] = 'regular',
-      [4] = 'first',
-      [5] = 'second',
-    },
-%    \end{macrocode}
-%
-% \noindent
-% Nodes without subtypes:
-% \begin{compactitem}
-% \item whatsit (8)
-% \item local\_par (9)
-% \item dir (10)
-% \end{compactitem}
-%
-% \paragraph{math (11)}
-%    \begin{macrocode}
-    math = {
-      [0] = 'beginmath',
-      [1] = 'endmath',
-    },
-%    \end{macrocode}
-% \paragraph{glue (12)}
-%    \begin{macrocode}
-    glue = {
-      [0]   = 'userskip',
-      [1]   = 'lineskip',
-      [2]   = 'baselineskip',
-      [3]   = 'parskip',
-      [4]   = 'abovedisplayskip',
-      [5]   = 'belowdisplayskip',
-      [6]   = 'abovedisplayshortskip',
-      [7]   = 'belowdisplayshortskip',
-      [8]   = 'leftskip',
-      [9]   = 'rightskip',
-      [10]  = 'topskip',
-      [11]  = 'splittopskip',
-      [12]  = 'tabskip',
-      [13]  = 'spaceskip',
-      [14]  = 'xspaceskip',
-      [15]  = 'parfillskip',
-      [16]  = 'mathskip',
-      [17]  = 'thinmuskip',
-      [18]  = 'medmuskip',
-      [19]  = 'thickmuskip',
-      [98]  = 'conditionalmathskip',
-      [99]  = 'muglue',
-      [100] = 'leaders',
-      [101] = 'cleaders',
-      [102] = 'xleaders',
-      [103] = 'gleaders',
-    },
-%    \end{macrocode}
-% \paragraph{kern (13)}
-%    \begin{macrocode}
-    kern = {
-      [0] = 'fontkern',
-      [1] = 'userkern',
-      [2] = 'accentkern',
-      [3] = 'italiccorrection',
-    },
-%    \end{macrocode}
-%
-% \noindent
-% Nodes without subtypes:
-% \begin{compactitem}
-% \item penalty (14)
-% \item unset (15)
-% \item style (16)
-% \item choice (17)
-% \end{compactitem}
-%
-% \paragraph{noad (18)}
 %    \begin{macrocode}
-    noad = {
-      [0] = 'ord',
-      [1] = 'opdisplaylimits',
-      [2] = 'oplimits',
-      [3] = 'opnolimits',
-      [4] = 'bin',
-      [5] = 'rel',
-      [6] = 'open',
-      [7] = 'close',
-      [8] = 'punct',
-      [9] = 'inner',
-      [10] = 'under',
-      [11] = 'over',
-      [12] = 'vcenter',
-    },
-%    \end{macrocode}
-% \paragraph{radical (19)}
-%    \begin{macrocode}
-    radical = {
-      [0] = 'radical',
-      [1] = 'uradical',
-      [2] = 'uroot',
-      [3] = 'uunderdelimiter',
-      [4] = 'uoverdelimiter',
-      [5] = 'udelimiterunder',
-      [6] = 'udelimiterover',
-    },
+\NeedsTeXFormat{LaTeX2e}[1994/06/01]
+\ProvidesPackage{nodetree-embed}
+  [2020/05/29 v2.0 Embed node trees into a LaTeX document]
 %    \end{macrocode}
 %
-% \noindent
-% Nodes without subtypes:
-% \begin{compactitem}
-% \item fraction (20)
-% \end{compactitem}
-%
-% \paragraph{accent (21)}
-%    \begin{macrocode}
-    accent = {
-      [0] = 'bothflexible',
-      [1] = 'fixedtop',
-      [2] = 'fixedbottom',
-      [3] = 'fixedboth',
-    },
-%    \end{macrocode}
-% \paragraph{fence (22)}
 %    \begin{macrocode}
-    fence = {
-      [0] = 'unset',
-      [1] = 'left',
-      [2] = 'middle',
-      [3] = 'right',
-    },
+\RequirePackage{xcolor,mdframed,expl3,xparse,fontspec}
 %    \end{macrocode}
 %
-% \noindent
-% Nodes without subtypes:
-% \begin{compactitem}
-% \item math\_char (23)
-% \item sub\_box (24)
-% \item sub\_mlist (25)
-% \item math\_text\_char (26)
-% \item delim (27)
-% \item margin\_kern (28)
-% \end{compactitem}
-%
-% \paragraph{glyph (29)}
 %    \begin{macrocode}
-    glyph = {
-      [0] = 'character',
-      [1] = 'ligature',
-      [2] = 'ghost',
-      [3] = 'left',
-      [4] = 'right',
-    },
-%    \end{macrocode}
-%
-% \noindent
-% Nodes without subtypes:
-% \begin{compactitem}
-% \item align\_record (30)
-% \item pseudo\_file (31)
-% \item pseudo\_line (32)
-% \item page\_insert (33)
-% \item split\_insert (34)
-% \item expr\_stack (35)
-% \item nested\_list (36)
-% \item span (37)
-% \item attribute (38)
-% \item glue\_spec (39)
-% \item attribute\_list (40)
-% \item temp (41)
-% \item align\_stack (42)
-% \item movement\_stack (43)
-% \item if\_stack (44)
-% \item unhyphenated (45)
-% \item hyphenated (46)
-% \item delta (47)
-% \item passive (48)
-% \item shape (49)
-% \end{compactitem}
-%    \begin{macrocode}
-  }
-  subtypes.whatsit = node.whatsits()
-  local out = ''
-  if subtypes[typ] and subtypes[typ][n.subtype] then
-    out = subtypes[typ][n.subtype]
-    if options.verbosity > 1 then
-      out = out .. tpl.type_id(n.subtype)
-    end
-    return out
-  else
-    return tostring(n.subtype)
-  end
-  assert(false)
-end
-%    \end{macrocode}
-%
-% \subsubsection{tpl --- Template function}
-%
-%    \begin{macrocode}
-function tpl.round(number)
-  local mult = 10^(options.decimalplaces or 0)
-  return math.floor(number * mult + 0.5) / mult
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.length(input)
-  input = tonumber(input)
-  input = input / tex.sp('1' .. options.unit)
-  return string.format('%g%s', tpl.round(input), options.unit)
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.fill(number, order, field)
-  if order ~= nil and order ~= 0 then
-    if field == 'stretch' then
-      out = '+'
-    else
-      out = '-'
-    end
-    return out .. string.format(
-      '%gfi%s', number / 2^16,
-      string.rep('l', order - 1)
-    )
-  else
-    return tpl.length(number)
-  end
-end
+\input{nodetree}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-tpl.node_colors = {
-  hlist = {'red', 'bright'},
-  vlist = {'green', 'bright'},
-  rule = {'blue', 'bright'},
-  ins = {'blue'},
-  mark = {'magenta'},
-  adjust = {'cyan'},
-  boundary = {'red', 'bright'},
-  disc = {'green', 'bright'},
-  whatsit = {'yellow', 'bright'},
-  local_par = {'blue', 'bright'},
-  dir = {'magenta', 'bright'},
-  math = {'cyan', 'bright'},
-  glue = {'magenta', 'bright'},
-  kern = {'green', 'bright'},
-  penalty = {'yellow', 'bright'},
-  unset = {'blue'},
-  style = {'magenta'},
-  choice = {'cyan'},
-  noad = {'red'},
-  radical = {'green'},
-  fraction = {'yellow'},
-  accent = {'blue'},
-  fence = {'magenta'},
-  math_char = {'cyan'},
-  sub_box = {'red', 'bright'},
-  sub_mlist = {'green', 'bright'},
-  math_text_char = {'yellow', 'bright'},
-  delim = {'blue', 'bright'},
-  margin_kern = {'magenta', 'bright'},
-  glyph = {'cyan', 'bright'},
-  align_record = {'red'},
-  pseudo_file = {'green'},
-  pseudo_line = {'yellow'},
-  page_insert = {'blue'},
-  split_insert = {'magenta'},
-  expr_stack = {'cyan'},
-  nested_list = {'red'},
-  span = {'green'},
-  attribute = {'yellow'},
-  glue_spec = {'magenta'},
-  attribute_list = {'cyan'},
-  temp = {'magenta'},
-  align_stack = {'red', 'bright'},
-  movement_stack = {'green', 'bright'},
-  if_stack = {'yellow', 'bright'},
-  unhyphenated = {'magenta', 'bright'},
-  hyphenated = {'cyan', 'bright'},
-  delta = {'red'},
-  passive = {'green'},
-  shape = {'yellow'},
+\RequirePackage{kvoptions}
+\SetupKeyvalOptions{
+  family=NTE,
+  prefix=NTEK@
 }
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function tpl.color_code(code)
-  return string.char(27) .. '[' .. tostring(code) .. 'm'
-end
-%    \end{macrocode}
-%
-% \begin{code}
-% local colors = {
-%     -- attributes
-%     reset = 0,
-%     clear = 0,
-%     bright = 1,
-%     dim = 2,
-%     underscore = 4,
-%     blink = 5,
-%     reverse = 7,
-%     hidden = 8,
-%
-%     -- foreground
-%     black = 30,
-%     red = 31,
-%     green = 32,
-%     yellow = 33,
-%     blue = 34,
-%     magenta = 35,
-%     cyan = 36,
-%     white = 37,
-%
-%     -- background
-%     onblack = 40,
-%     onred = 41,
-%     ongreen = 42,
-%     onyellow = 43,
-%     onblue = 44,
-%     onmagenta = 45,
-%     oncyan = 46,
-%     onwhite = 47,
-% }
-% \end{code}
-%    \begin{macrocode}
-function tpl.color(color, mode, background)
-  if options.color ~= 'colored' then
-    return ''
-  end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  local out = ''
-  local code = ''
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  if mode == 'bright' then
-    out = tpl.color_code(1)
-  elseif mode == 'dim' then
-    out = tpl.color_code(2)
-  end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  if not background then
-    if color == 'reset' then code = 0
-    elseif color == 'red' then code = 31
-    elseif color == 'green' then code = 32
-    elseif color == 'yellow' then code = 33
-    elseif color == 'blue' then code = 34
-    elseif color == 'magenta' then code = 35
-    elseif color == 'cyan' then code = 36
-    else code = 37 end
-  else
-    if color == 'black' then code = 40
-    elseif color == 'red' then code = 41
-    elseif color == 'green' then code = 42
-    elseif color == 'yellow' then code = 43
-    elseif color == 'blue' then code = 44
-    elseif color == 'magenta' then code = 45
-    elseif color == 'cyan' then code = 46
-    elseif color == 'white' then code = 47
-    else code = 40 end
-  end
-  return out .. tpl.color_code(code)
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.key_value(key, value)
-  local out = tpl.color('yellow') .. key .. ': '
-  if value then
-    out = out .. tpl.color('white') .. value .. '; '
-  end
-  return out .. tpl.color('reset')
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.char(input)
-  return string.format('%q', unicode.utf8.char(input))
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.type(type, id)
-  local out = tpl.color(
-    tpl.node_colors[type][1],
-    tpl.node_colors[type][2]
-    )
-    .. string.upper(type)
-  if options.verbosity > 1 then
-    out = out .. tpl.type_id(id)
-  end
-  return out .. tpl.color('reset')  .. ' '
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.callback_variable(variable_name, variable)
-  if variable ~= nil and variable ~= '' then
-    tpl.print(variable_name .. ': ' .. tostring(variable))
-  end
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.line(length)
-  if length == 'long' then
-    return '------------------------------------------'
-  else
-    return '-----------------------'
-  end
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.callback(callback_name, variables)
-  tpl.print('\n\n')
-  tpl.print('Callback: ' .. tpl.color('red', '', true) ..
-    callback_name .. tpl.color('reset')
-  )
-  if variables then
-    for name, value in pairs(variables) do
-      if value ~= nil and value ~= '' then
-        tpl.print('  - ' .. name .. ': ' .. tostring(value))
-      end
-    end
-  end
-  tpl.print(tpl.line('long'))
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.type_id(id)
-  return '[' .. tostring(id) .. ']'
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.branch(connection_type, connection_state, last)
-  local c = connection_type
-  local s = connection_state
-  local l = last
-  if c == 'list' and s == 'stop' and l == false then
-    return '  '
-  elseif c == 'field' and s == 'stop' and l == false then
-    return '  '
-  elseif c == 'list' and s == 'continue' and l == false then
-    return '│ '
-  elseif c == 'field' and s == 'continue' and l == false then
-    return '║ '
-  elseif c == 'list' and s == 'continue' and l == true then
-    return '├─'
-  elseif c == 'field' and s == 'continue' and l == true then
-    return '╠═'
-  elseif c == 'list' and s == 'stop' and l == true then
-    return '└─'
-  elseif c == 'field' and s == 'stop' and l == true then
-    return '╚═'
-  end
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.branches(level, connection_type)
-  local out = ''
-  for i = 1, level - 1  do
-    out = out .. tpl.branch('list', tree.state[i]['list'], false)
-    out = out .. tpl.branch('field', tree.state[i]['field'], false)
-  end
-%    \end{macrocode}
-% Format the last branches
-%    \begin{macrocode}
-  if connection_type == 'list' then
-    out = out .. tpl.branch('list', tree.state[level]['list'], true)
-  else
-    out = out .. tpl.branch('list', tree.state[level]['list'], false)
-    out = out .. tpl.branch('field', tree.state[level]['field'], true)
-  end
-  return out
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tpl.print(text)
-
-  if options.channel == 'log' then
-    if not log then
-      log = io.open(tex.jobname .. '_nodetree.log', 'a')
-    end
-    log:write(text, '\n')
-  else
-    print('  ' .. text)
-  end
-end
-%    \end{macrocode}
-%
-% \subsubsection{tree --- Build the node tree}
-%
-%    \begin{macrocode}
-function tree.format_field(head, field)
-  local out = ''
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  if not head[field] or head[field] == 0 then
-    return ''
-  end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  if options.verbosity < 2 and
-    -- glyph
-    field == 'font' or
-    field == 'left' or
-    field == 'right' or
-    field == 'uchyph' or
-    -- hlist
-    field == 'dir' or
-    field == 'glue_order' or
-    field == 'glue_sign' or
-    field == 'glue_set' or
-    -- glue
-    field == 'stretch_order' then
-    return ''
-  elseif options.verbosity < 3 and
-    field == 'prev' or
-    field == 'next' or
-    field == 'id'
-  then
-    return ''
-  end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  if field == 'prev' or field == 'next' then
-    out = nodex.node_id(head[field])
-  elseif field == 'subtype' then
-    out = nodex.subtype(head)
-  elseif
-    field == 'width' or
-    field == 'height' or
-    field == 'depth' or
-    field == 'kern' or
-    field == 'shift' then
-    out = tpl.length(head[field])
-  elseif field == 'char' then
-    out = tpl.char(head[field])
-  elseif field == 'glue_set' then
-    out = tpl.round(head[field])
-  elseif field == 'stretch' or field == 'shrink' then
-    out = tpl.fill(head[field], head[field .. '_order'], field)
-  else
-    out = tostring(head[field])
-  end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  return tpl.key_value(field, out)
-end
-%    \end{macrocode}
-%
-% |level| is a integer beginning with 1. The variable |connection_type|
-% is a string, which can be either |list| or |field|. The variable
-% |connection_state| is a string, which can be either |continue| or
-% |stop|.
-%    \begin{macrocode}
-function tree.set_state(level, connection_type, connection_state)
-  if not tree.state[level] then
-    tree.state[level] = {}
-  end
-  tree.state[level][connection_type] = connection_state
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tree.analyze_fields(fields, level)
-  local max = 0
-  local connection_state = ''
-  for _ in pairs(fields) do
-    max = max + 1
-  end
-  local count = 0
-  for field_name, recursion_node in pairs(fields) do
-    count = count + 1
-    if count == max then
-      connection_state = 'stop'
-    else
-      connection_state = 'continue'
-    end
-    tree.set_state(level, 'field', connection_state)
-    tpl.print(tpl.branches(level, 'field') .. tpl.key_value(field_name))
-    tree.analyze_list(recursion_node, level + 1)
-  end
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tree.analyze_node(head, level)
-  local connection_state
-  local out = ''
-  if head.next then
-    connection_state = 'continue'
-  else
-    connection_state = 'stop'
-  end
-  tree.set_state(level, 'list', connection_state)
-  out = tpl.branches(level, 'list')
-    .. tpl.type(node.type(head.id), head.id)
-  if options.verbosity > 1 then
-    out = out .. tpl.key_value('no', nodex.node_id(head))
-  end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  local fields = {}
-  for field_id, field_name in pairs(node.fields(head.id, head.subtype)) do
-    if field_name ~= 'next' and
-      field_name ~= 'prev' and
-      node.is_node(head[field_name]) then
-      fields[field_name] = head[field_name]
-    else
-      out = out .. tree.format_field(head, field_name)
-    end
-  end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  tpl.print(out)
-  tree.analyze_fields(fields, level)
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tree.analyze_list(head, level)
-  while head do
-    tree.analyze_node(head, level)
-    head = head.next
-  end
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function tree.analyze_callback(head)
-  tree.analyze_list(head, 1)
-  tpl.print(tpl.line('short') .. '\n')
-end
-%    \end{macrocode}
-%
-% \subsubsection{callbacks --- Callback wrapper}
-%
-%    \begin{macrocode}
-function callbacks.contribute_filter(extrainfo)
-  tpl.callback('contribute_filter', {extrainfo = extrainfo})
-  return true
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function callbacks.buildpage_filter(extrainfo)
-  tpl.callback('buildpage_filter', {extrainfo = extrainfo})
-  return true
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function callbacks.pre_linebreak_filter(head, groupcode)
-  tpl.callback('pre_linebreak_filter', {groupcode = groupcode})
-  tree.analyze_callback(head)
-  return true
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function callbacks.linebreak_filter(head, is_display)
-  tpl.callback('linebreak_filter', {is_display = is_display})
-  tree.analyze_callback(head)
-  return true
-end
-%    \end{macrocode}
-%
-% TODO: Fix return values, page output
-%    \begin{macrocode}
-function callbacks.append_to_vlist_filter(head, locationcode, prevdepth, mirrored)
-  local variables = {
-    locationcode = locationcode,
-    prevdepth = prevdepth,
-    mirrored = mirrored,
-  }
-  tpl.callback('append_to_vlist_filter', variables)
-  tree.analyze_callback(head)
-  return true
-end
+\directlua{
+  nodetree = require('nodetree')
+  nodetree.check_shell_escape()
+}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.post_linebreak_filter(head, groupcode)
-  tpl.callback('post_linebreak_filter', {groupcode = groupcode})
-  tree.analyze_callback(head)
-  return true
-end
+\define@key{NTE}{callback}[]{\NodetreeSetOption[callback]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.hpack_filter(head, groupcode, size, packtype, direction, attributelist)
-  local variables = {
-    groupcode = groupcode,
-    size = size,
-    packtype = packtype,
-    direction = direction,
-    attributelist = attributelist,
-  }
-  tpl.callback('hpack_filter', variables)
-  tree.analyze_callback(head)
-  return true
-end
+\DeclareStringOption[1]{verbosity}
+\define@key{NTE}{verbosity}[]{\NodetreeSetOption[verbosity]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.vpack_filter(head, groupcode, size, packtype, maxdepth, direction, attributelist)
-  local variables = {
-    groupcode = groupcode,
-    size = size,
-    packtype = packtype,
-    maxdepth = tpl.length(maxdepth),
-    direction = direction,
-    attributelist = attributelist,
-  }
-  tpl.callback('vpack_filter', variables)
-  tree.analyze_callback(head)
-  return true
-end
+\DeclareStringOption[colored]{color}
+\define@key{NTE}{color}[]{\NodetreeSetOption[color]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.hpack_quality(incident, detail, head, first, last)
-  local variables = {
-    incident = incident,
-    detail = detail,
-    first = first,
-    last = last,
-  }
-  tpl.callback('hpack_quality', variables)
-  tree.analyze_callback(head)
-end
+\DeclareStringOption[1]{unit}
+\define@key{NTE}{unit}[]{\NodetreeSetOption[unit]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.vpack_quality(incident, detail, head, first, last)
-  local variables = {
-    incident = incident,
-    detail = detail,
-    first = first,
-    last = last,
-  }
-  tpl.callback('vpack_quality', variables)
-  tree.analyze_callback(head)
-end
+\DeclareStringOption[1]{decimalplaces}
+\define@key{NTE}{decimalplaces}[]{\NodetreeSetOption[decimalplaces]{#1}}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.process_rule(head, width, height)
-  local variables = {
-    width = width,
-    height = height,
-  }
-  tpl.callback('process_rule', variables)
-  tree.analyze_callback(head)
-  return true
-end
+\DeclareStringOption[monokaisoda]{theme}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.pre_output_filter(head, groupcode, size, packtype, maxdepth, direction)
-  local variables = {
-    groupcode = groupcode,
-    size = size,
-    packtype = packtype,
-    maxdepth = maxdepth,
-    direction = direction,
-  }
-  tpl.callback('pre_output_filter', variables)
-  tree.analyze_callback(head)
-  return true
-end
+\DeclareStringOption[dark]{thememode}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.hyphenate(head, tail)
-  tpl.callback('hyphenate')
-  tpl.print('head:')
-  tree.analyze_callback(head)
-  tpl.print('tail:')
-  tree.analyze_callback(tail)
-end
+\DeclareStringOption[Ubuntu Mono]{font}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.ligaturing(head, tail)
-  tpl.callback('ligaturing')
-  tpl.print('head:')
-  tree.analyze_callback(head)
-  tpl.print('tail:')
-  tree.analyze_callback(tail)
-end
+\DeclareStringOption[\footnotesize]{fontsize}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.kerning(head, tail)
-  tpl.callback('kerning')
-  tpl.print('head:')
-  tree.analyze_callback(head)
-  tpl.print('tail:')
-  tree.analyze_callback(tail)
-end
+\DeclareBoolOption{showmarkup}
 %    \end{macrocode}
 %
 %    \begin{macrocode}
-function callbacks.insert_local_par(local_par, location)
-  tpl.callback('insert_local_par', {location = location})
-  tree.analyze_callback(local_par)
-  return true
-end
+\ProcessKeyvalOptions{NTE}
 %    \end{macrocode}
 %
+% \begin{macro}{\NTE@colors}
 %    \begin{macrocode}
-function callbacks.mlist_to_hlist(head, display_type, need_penalties)
-  local variables = {
-    display_type = display_type,
-    need_penalties = need_penalties,
+\ExplSyntaxOn
+\def\NTE@colors{
+  \str_case_e:nn{\NTEK@theme}{
+    {bwdark}{
+      \definecolor{NTEblack}{gray}{0}
+      \definecolor{NTEred}{gray}{1}
+      \definecolor{NTEgreen}{gray}{1}
+      \definecolor{NTEyellow}{gray}{1}
+      \definecolor{NTEblue}{gray}{1}
+      \definecolor{NTEmagenta}{gray}{1}
+      \definecolor{NTEcyan}{gray}{1}
+      \definecolor{NTEwhite}{gray}{1}
+      \definecolor{NTEblackbright}{gray}{0}
+      \definecolor{NTEredbright}{gray}{1}
+      \definecolor{NTEgreenbright}{gray}{1}
+      \definecolor{NTEyellowbright}{gray}{1}
+      \definecolor{NTEbluebright}{gray}{1}
+      \definecolor{NTEmagentabright}{gray}{1}
+      \definecolor{NTEcyanbright}{gray}{1}
+      \definecolor{NTEwhitebright}{gray}{1}
+    }
+    {bwlight}{
+      \definecolor{NTEblack}{gray}{0}
+      \definecolor{NTEred}{gray}{0}
+      \definecolor{NTEgreen}{gray}{0}
+      \definecolor{NTEyellow}{gray}{0}
+      \definecolor{NTEblue}{gray}{0}
+      \definecolor{NTEmagenta}{gray}{0}
+      \definecolor{NTEcyan}{gray}{0}
+      \definecolor{NTEwhite}{gray}{1}
+      \definecolor{NTEblackbright}{gray}{0}
+      \definecolor{NTEredbright}{gray}{0}
+      \definecolor{NTEgreenbright}{gray}{0}
+      \definecolor{NTEyellowbright}{gray}{0}
+      \definecolor{NTEbluebright}{gray}{0}
+      \definecolor{NTEmagentabright}{gray}{0}
+      \definecolor{NTEcyanbright}{gray}{0}
+      \definecolor{NTEwhitebright}{gray}{1}
+    }
+    {monokaisoda}{
+      \definecolor{NTEblack}{HTML}{1a1a1a}
+      \definecolor{NTEred}{HTML}{f4005f}
+      \definecolor{NTEgreen}{HTML}{98e024}
+      \definecolor{NTEyellow}{HTML}{fa8419}
+      \definecolor{NTEblue}{HTML}{9d65ff}
+      \definecolor{NTEmagenta}{HTML}{f4005f}
+      \definecolor{NTEcyan}{HTML}{58d1eb}
+      \definecolor{NTEwhite}{HTML}{c4c5b5}
+      \definecolor{NTEblackbright}{HTML}{625e4c}
+      \definecolor{NTEredbright}{HTML}{f4005f}
+      \definecolor{NTEgreenbright}{HTML}{98e024}
+      \definecolor{NTEyellowbright}{HTML}{e0d561}
+      \definecolor{NTEbluebright}{HTML}{9d65ff}
+      \definecolor{NTEmagentabright}{HTML}{f4005f}
+      \definecolor{NTEcyanbright}{HTML}{58d1eb}
+      \definecolor{NTEwhitebright}{HTML}{f6f6ef}
+    }
   }
-  tpl.callback('mlist_to_hlist', variables)
-  tree.analyze_callback(head)
-  return node.mlist_to_hlist(head, display_type, need_penalties)
-end
-%    \end{macrocode}
-%
-% \subsubsection{base --- Exported base functions}
-%
-%    \begin{macrocode}
-function base.normalize_options()
-  options.verbosity = tonumber(options.verbosity)
-  options.decimalplaces = tonumber(options.decimalplaces)
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function base.set_default_options()
-  local defaults = {
-    verbosity = 1,
-    callback = 'postlinebreak',
-    engine = 'luatex',
-    color = 'colored',
-    decimalplaces = 2,
-    unit = 'pt',
-    channel = 'term',
+  \str_case_e:nn{\NTEK@thememode}{
+    {dark}{
+      \definecolor{NTEbackground}{named}{NTEblack}
+      \definecolor{NTEfont}{named}{NTEwhitebright}
+    }
+    {light}{
+      \definecolor{NTEbackground}{named}{NTEwhitebright}
+      \definecolor{NTEfont}{named}{NTEblack}
+    }
   }
-  if not options then
-    options = {}
-  end
-  for key, value in pairs(defaults) do
-    if not options[key] then
-      options[key] = value
-    end
-  end
-  base.normalize_options()
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function base.set_option(key, value)
-  if not options then
-    options = {}
-  end
-  options[key] = value
-  base.normalize_options()
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function base.get_option(key)
-  if not options then
-    options = {}
-  end
-  if options[key] then
-    return options[key]
-  end
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function base.get_callback_name(alias)
-  if alias == 'contribute' or alias == 'contributefilter' then
-    return 'contribute_filter'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'buildpage' or alias == 'buildpagefilter' then
-    return 'buildpage_filter'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'preline' or alias == 'prelinebreakfilter' then
-    return 'pre_linebreak_filter'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'line' or alias == 'linebreakfilter' then
-    return 'linebreak_filter'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'append' or alias == 'appendtovlistfilter' then
-    return 'append_to_vlist_filter'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'postline' or alias == 'postlinebreakfilter' then
-    return 'post_linebreak_filter'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'hpack' or alias == 'hpackfilter' then
-    return 'hpack_filter'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'vpack' or alias == 'vpackfilter' then
-    return 'vpack_filter'
-%    \end{macrocode}
-% TODO: Fix: Unable to register callback
-%    \begin{macrocode}
-  elseif alias == 'hpackq' or alias == 'hpackquality' then
-    return 'hpack_quality'
-%    \end{macrocode}
-% TODO: Fix: Unable to register callback
-%    \begin{macrocode}
-  elseif alias == 'vpackq' or alias == 'vpackquality' then
-    return 'vpack_quality'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'process' or alias == 'processrule' then
-    return 'process_rule'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'preout' or alias == 'preoutputfilter' then
-    return 'pre_output_filter'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'hyph' or alias == 'hyphenate' then
-    return 'hyphenate'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'liga' or alias == 'ligaturing' then
-    return 'ligaturing'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'kern' or alias == 'kerning' then
-   return 'kerning'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'insert' or alias == 'insertlocalpar' then
-    return 'insert_local_par'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  elseif alias == 'mhlist' or alias == 'mlisttohlist' then
-    return 'mlist_to_hlist'
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-  else
-    return 'post_linebreak_filter'
-  end
-end
-%    \end{macrocode}
-%
-%    \begin{macrocode}
-function base.register(cb)
-  if options.engine == 'lualatex' then
-    luatexbase.add_to_callback(cb, callbacks[cb], 'nodetree')
-  else
-    id, error = callback.register(cb, callbacks[cb])
-  end
-end
+}
+\ExplSyntaxOff
 %    \end{macrocode}
+% \end{macro}
 %
+% \begin{macro}{\NTE@fonts}
 %    \begin{macrocode}
-function base.register_callbacks()
-  for alias in string.gmatch(options.callback, '([^,]+)') do
-    base.register(base.get_callback_name(alias))
-  end
-end
+\def\NTE@fonts{
+  \bfseries%
+  \NTEK@fontsize%
+  \setmonofont{\NTEK@font}%
+  \ttfamily%
+  \setlength{\parindent}{0pt}%
+  \setlength{\parskip}{-0.9pt}%
+}
 %    \end{macrocode}
+% \end{macro}
 %
+% \begin{macro}{\NodetreeSet}
+% Same definition as in nodetree.sty. Only implement this command
+% if not already registers.
 %    \begin{macrocode}
-function base.unregister(cb)
-  if options.engine == 'lualatex' then
-    luatexbase.remove_from_callback(cb, 'nodetree')
-  else
-    id, error = callback.register(cb, nil)
-  end
-end
+\providecommand{\NodetreeSet}[1]{%
+  \setkeys{NTE}{#1}%
+}
 %    \end{macrocode}
+% \end{macro}
 %
 %    \begin{macrocode}
-function base.unregister_callbacks()
-  for alias in string.gmatch(options.callback, '([^,]+)') do
-    base.unregister(base.get_callback_name(alias))
-  end
-end
+\newenvironment{NodetreeEmbedView}[1][]{
+  \setkeys{NTE}{#1}
+  \NTE@colors
+  \begin{mdframed}[
+    linecolor=black,
+    backgroundcolor=NTEbackground,
+    fontcolor=NTEfont,
+  ]%
+  \NTE@fonts
+}{
+  \end{mdframed}%
+}
 %    \end{macrocode}
 %
-%    \begin{macrocode}
-function base.execute()
-  local c = base.get_callback()
-  if options.engine == 'lualatex' then
-    luatexbase.add_to_callback(c, callbacks.post_linebreak_filter, 'nodetree')
-  else
-    id, error = callback.register(c, callbacks.post_linebreak_filter)
-  end
-end
+% \begin{environment}{NodetreeEmbedEnv}
+%    \begin{macrocode}
+\NewDocumentEnvironment { NodetreeEmbedEnv } { O{} +b } {
+  \setkeys{NTE}{#1}
+  \ifNTEK@showmarkup
+    \noindent
+    \texttt{\detokenize{#2}}
+  \else
+  \fi
+  \NTE@colors
+  \begin{NodetreeEmbedView}
+    \directlua{
+      nodetree.compile_include('\luaescapestring{\unexpanded{#2}}')
+    }
+  \end{NodetreeEmbedView}
+}{}
+%    \end{macrocode}
+% \end{environment}
+
+% \begin{macro}{\NodetreeEmbedCmd}
+%    \begin{macrocode}
+\NewDocumentCommand { \NodetreeEmbedCmd } { O{} +v } {
+  \setkeys{NTE}{#1}
+  \ifNTEK@showmarkup
+    \noindent
+    \texttt{#2}
+  \else
+  \fi
+  \NTE@colors
+  \begin{NodetreeEmbedView}
+    \directlua{
+      nodetree.compile_include('\luaescapestring{\unexpanded{#2}}')
+    }
+  \end{NodetreeEmbedView}
+}
 %    \end{macrocode}
+% \end{macro}
 %
+% \begin{macro}{\NodetreeEmbedInput}
 %    \begin{macrocode}
-function base.analyze(head)
-  tpl.print('\n')
-  tree.analyze_list(head, 1)
-end
+\newcommand{\NodetreeEmbedInput}[2][]{
+  \setkeys{NTE}{#1}
+  \begin{NodetreeEmbedView}
+  \input{#2.nttex}
+  \end{NodetreeEmbedView}
+}
+\let\nodetreeterminalemulator\NodetreeEmbedInput
 %    \end{macrocode}
+% \end{macro}
 %
-%    \begin{macrocode}
-return base
-%    \end{macrocode}
+\endinput
 % \iffalse
-%</luamain>
+%</packageembed>
 % \fi
 %
 % \Finale
diff --git a/macros/luatex/generic/nodetree/nodetree.ins b/macros/luatex/generic/nodetree/nodetree.ins
index 85d250818e..9b187ab25c 100644
--- a/macros/luatex/generic/nodetree/nodetree.ins
+++ b/macros/luatex/generic/nodetree/nodetree.ins
@@ -1,4 +1,4 @@
-% Copyright (C) 2016 by Josef Friedrich <josef@friedrich.rocks>
+% Copyright (C) 2016-2020 by Josef Friedrich <josef@friedrich.rocks>
 % ----------------------------------------------------------------------
 % This work may be distributed and/or modified under the conditions of
 % the LaTeX Project Public License, either version 1.3c of this license
@@ -21,7 +21,7 @@
 
 This is a generated file.
 
-Copyright (C) 2016 by Josef Friedrich <josef@friedrich.rocks>
+Copyright (C) 2016-2020 by Josef Friedrich <josef@friedrich.rocks>
 ----------------------------------------------------------------------
 This work may be distributed and/or modified under the conditions of
 the LaTeX Project Public License, either version 1.3c of this license
@@ -37,11 +37,7 @@ version 2008/05/05 or later.
 
 \generate{\file{nodetree.tex}{\from{nodetree.dtx}{tex}}}
 \generate{\file{nodetree.sty}{\from{nodetree.dtx}{package}}}
-
-\nopreamble
-\nopostamble
-\generate{\file{nodetree.lua}{\from{nodetree.dtx}{luamain}}}
-\generate{\file{README.md}{\from{nodetree.dtx}{readme}}}
+\generate{\file{nodetree-embed.sty}{\from{nodetree.dtx}{packageembed}}}
 
 \obeyspaces
 \Msg{*************************************************************}
diff --git a/macros/luatex/generic/nodetree/nodetree.lua b/macros/luatex/generic/nodetree/nodetree.lua
new file mode 100644
index 0000000000..666413578d
--- /dev/null
+++ b/macros/luatex/generic/nodetree/nodetree.lua
@@ -0,0 +1,1547 @@
+--- The nodetree package.
+--
+-- Nodetree uses [LDoc](https://github.com/stevedonovan/ldoc) for the
+--  source code documentation. The supported tags are described on in
+--  the [wiki](https://github.com/stevedonovan/LDoc/wiki).
+--
+-- Nodes in LuaTeX are connected. The nodetree view distinguishs
+-- between the `list` and `field` connections.
+--
+-- * `list`: Nodes, which are double connected by `next` and
+--   `previous` fields.
+-- * `field`: Connections to nodes by other fields than `next` and
+--   `previous` fields, e. g. `head`, `pre`.
+-- @module nodetree
+
+-- luacheck: globals node tex luatexbase lfs callback os unicode status modules
+
+if not modules then modules = { } end modules ['nodetree'] = {
+  version   = '2.0',
+  comment   = 'nodetree',
+  author    = 'Josef Friedrich',
+  copyright = 'Josef Friedrich',
+  license   = 'The LaTeX Project Public License Version 1.3c 2008-05-04'
+}
+
+--- A counter for the compiled TeX examples. Some TeX code snippets
+-- a written into file, wrapped with some TeX boilerplate code.
+-- This written files are compiled.
+local example_counter = 0
+
+--- The default options
+local default_options = {
+  callback = 'post_linebreak_filter',
+  channel = 'term',
+  color = 'colored',
+  decimalplaces = 2,
+  engine = 'luatex', -- Required for the callback registration
+  unit = 'pt',
+  verbosity = 1,
+}
+
+--- The current options
+-- They are changed very often.
+local options = {}
+for key, value in pairs(default_options) do
+  options[key] = value
+end
+
+if arg[0] == 'lualatex' then
+  options.engine = 'lualatex'
+end
+
+--- File descriptor
+local output_file
+
+--- The lua table named `tree_state` holds state values of the current
+-- tree item.
+--
+-- `tree_state`:
+--
+-- * `1` (level):
+--   * `list`: `continue`
+--   * `field`: `stop`
+-- * `2`:
+--   * `list`: `continue`
+--   * `field`: `stop`
+-- @table
+local tree_state = {}
+
+--- Format functions.
+--
+-- Low level template functions.
+--
+-- @section format
+
+local format = {
+  ---
+  -- @treturn string
+  underscore = function(string)
+    if options.channel == 'tex' then
+      return string.gsub(string, '_', '\\_')
+    else
+      return string
+    end
+  end,
+
+  ---
+  -- @treturn string
+  escape = function(string)
+    if options.channel == 'tex' then
+      return string.gsub(string, [[\]], [[\string\]])
+    else
+      return string
+    end
+  end,
+
+  -- @treturn number
+  number = function(number)
+    local mult = 10^(options.decimalplaces or 0)
+    return math.floor(number * mult + 0.5) / mult
+  end,
+
+  ---
+  -- @treturn string
+  whitespace = function(count)
+    local whitespace
+    local output = ''
+    if options.channel == 'tex' then
+      whitespace = '\\hspace{0.5em}'
+    else
+      whitespace = ' '
+    end
+    if not count then
+      count = 1
+    end
+    for _ = 1, count do
+      output = output .. whitespace
+    end
+    return output
+  end,
+
+  ---
+  -- @treturn string
+  color_code = function(code)
+    return string.char(27) .. '[' .. tostring(code) .. 'm'
+  end,
+
+  ---
+  -- @treturn string
+  color_tex = function(color, mode)
+    if not mode then mode = '' end
+    return 'NTE' .. color .. mode
+  end,
+
+  ---
+  -- @treturn string
+  node_begin = function()
+    if options.channel == 'tex' then
+      return '\\mbox{'
+    else
+      return ''
+    end
+  end,
+
+  ---
+  -- @treturn string
+  node_end = function()
+    if options.channel == 'tex' then
+      return '}'
+    else
+      return ''
+    end
+  end,
+
+  ---
+  -- @treturn string
+  new_line = function(count)
+    local output = ''
+    if not count then
+      count = 1
+    end
+    local new_line
+    if options.channel == 'tex' then
+      new_line = '\\par{}'
+    else
+      new_line = '\n'
+    end
+
+    for _ = 1, count do
+      output = output .. new_line
+    end
+    return output
+  end,
+
+  ---
+  -- @treturn string
+  type_id = function(id)
+    return '[' .. tostring(id) .. ']'
+  end
+}
+
+--- Print the output to stdout or write it into a file (`output_file`).
+-- New text is appended.
+--
+-- @tparam string text A text string.
+--
+local function nodetree_print(text)
+  if options.channel == 'log' or options.channel == 'tex' then
+    output_file:write(text)
+  else
+    io.write(text)
+  end
+end
+
+--- Template functions.
+-- @section template
+
+local template = {
+  node_colors = {
+    hlist = {'red', 'bright'},
+    vlist = {'green', 'bright'},
+    rule = {'blue', 'bright'},
+    ins = {'blue'},
+    mark = {'magenta'},
+    adjust = {'cyan'},
+    boundary = {'red', 'bright'},
+    disc = {'green', 'bright'},
+    whatsit = {'yellow', 'bright'},
+    local_par = {'blue', 'bright'},
+    dir = {'magenta', 'bright'},
+    math = {'cyan', 'bright'},
+    glue = {'magenta', 'bright'},
+    kern = {'green', 'bright'},
+    penalty = {'yellow', 'bright'},
+    unset = {'blue'},
+    style = {'magenta'},
+    choice = {'cyan'},
+    noad = {'red'},
+    radical = {'green'},
+    fraction = {'yellow'},
+    accent = {'blue'},
+    fence = {'magenta'},
+    math_char = {'cyan'},
+    sub_box = {'red', 'bright'},
+    sub_mlist = {'green', 'bright'},
+    math_text_char = {'yellow', 'bright'},
+    delim = {'blue', 'bright'},
+    margin_kern = {'magenta', 'bright'},
+    glyph = {'cyan', 'bright'},
+    align_record = {'red'},
+    pseudo_file = {'green'},
+    pseudo_line = {'yellow'},
+    page_insert = {'blue'},
+    split_insert = {'magenta'},
+    expr_stack = {'cyan'},
+    nested_list = {'red'},
+    span = {'green'},
+    attribute = {'yellow'},
+    glue_spec = {'magenta'},
+    attribute_list = {'cyan'},
+    temp = {'magenta'},
+    align_stack = {'red', 'bright'},
+    movement_stack = {'green', 'bright'},
+    if_stack = {'yellow', 'bright'},
+    unhyphenated = {'magenta', 'bright'},
+    hyphenated = {'cyan', 'bright'},
+    delta = {'red'},
+    passive = {'green'},
+    shape = {'yellow'},
+  },
+
+  ---
+  -- [SGR (Select Graphic Rendition) Parameters](https://en.wikipedia.org/wiki/ANSI_escape_code#SGR_parameters)
+  --
+  -- __attributes__
+  --
+  -- | color      |code|
+  -- |------------|----|
+  -- | reset      |  0 |
+  -- | clear      |  0 |
+  -- | bright     |  1 |
+  -- | dim        |  2 |
+  -- | underscore |  4 |
+  -- | blink      |  5 |
+  -- | reverse    |  7 |
+  -- | hidden     |  8 |
+  --
+  -- __foreground__
+  --
+  -- | color      |code|
+  -- |------------|----|
+  -- | black      | 30 |
+  -- | red        | 31 |
+  -- | green      | 32 |
+  -- | yellow     | 33 |
+  -- | blue       | 34 |
+  -- | magenta    | 35 |
+  -- | cyan       | 36 |
+  -- | white      | 37 |
+  --
+  -- __background__
+  --
+  -- | color      |code|
+  -- |------------|----|
+  -- | onblack    | 40 |
+  -- | onred      | 41 |
+  -- | ongreen    | 42 |
+  -- | onyellow   | 43 |
+  -- | onblue     | 44 |
+  -- | onmagenta  | 45 |
+  -- | oncyan     | 46 |
+  -- | onwhite    | 47 |
+  --
+  -- @tparam string color A color name (`black`, `red`, `green`,
+  --   `yellow`, `blue`, `magenta`, `cyan`, `white`).
+  -- @tparam string mode `bright` or `dim`.
+  -- @tparam boolean background Colorize the background not the text.
+  --
+  -- @treturn string
+  color = function(color, mode, background)
+    if options.color ~= 'colored' then
+      return ''
+    end
+
+    local output = ''
+    local code
+
+    if mode == 'bright' then
+      output = format.color_code(1)
+    elseif mode == 'dim' then
+      output = format.color_code(2)
+    end
+
+    if not background then
+      if color == 'reset' then code = 0
+      elseif color == 'red' then code = 31
+      elseif color == 'green' then code = 32
+      elseif color == 'yellow' then code = 33
+      elseif color == 'blue' then code = 34
+      elseif color == 'magenta' then code = 35
+      elseif color == 'cyan' then code = 36
+      else code = 37 end
+    else
+      if color == 'black' then code = 40
+      elseif color == 'red' then code = 41
+      elseif color == 'green' then code = 42
+      elseif color == 'yellow' then code = 43
+      elseif color == 'blue' then code = 44
+      elseif color == 'magenta' then code = 45
+      elseif color == 'cyan' then code = 46
+      elseif color == 'white' then code = 47
+      else code = 40 end
+    end
+    return output .. format.color_code(code)
+  end,
+
+  --- Format a single unicode character.
+  --
+  -- @tparam string char A single input character.
+  --
+  -- @treturn string
+  char = function(char)
+    char = string.format('%s', unicode.utf8.char(char))
+    char = '\'' .. char .. '\''
+    if options.channel == 'tex' then
+      char = format.escape(char)
+    end
+    return char
+  end,
+
+  ---
+  -- @treturn string
+  line = function(length)
+    local output
+    if length == 'long' then
+      output = '------------------------------------------'
+    else
+      output = '-----------------------'
+    end
+      return output .. format.new_line()
+  end,
+
+  ---
+  -- @treturn string
+  branch = function(connection_type, connection_state, last)
+    local c = connection_type
+    local s = connection_state
+    local l = last
+    if c == 'list' and s == 'stop' and l == false then
+      return format.whitespace(2)
+    elseif c == 'field' and s == 'stop' and l == false then
+      return format.whitespace(2)
+    elseif c == 'list' and s == 'continue' and l == false then
+      return '│' .. format.whitespace()
+    elseif c == 'field' and s == 'continue' and l == false then
+      return '║' .. format.whitespace()
+    elseif c == 'list' and s == 'continue' and l == true then
+      return '├─'
+    elseif c == 'field' and s == 'continue' and l == true then
+      return '╠═'
+    elseif c == 'list' and s == 'stop' and l == true then
+      return '└─'
+    elseif c == 'field' and s == 'stop' and l == true then
+      return '╚═'
+    end
+    return ''
+  end,
+}
+
+---
+-- @treturn string
+function template.fill(number, order, field)
+  local output
+  if order ~= nil and order ~= 0 then
+    if field == 'stretch' then
+      output = '+'
+    else
+      output = '-'
+    end
+    return output .. string.format(
+      '%g%s', number / 2^16,
+      template.colored_string(
+        'fi' .. string.rep('l', order - 1),
+        'white',
+        'dim'
+      )
+    )
+  else
+    return template.length(number)
+  end
+end
+
+--- Colorize a text string.
+--
+-- @tparam string text A text string.
+-- @tparam string color A color name (`black`, `red`, `green`,
+--   `yellow`, `blue`, `magenta`, `cyan`, `white`).
+-- @tparam string mode `bright` or `dim`.
+-- @tparam boolean background Colorize the background not the text.
+--
+-- @treturn string
+function template.colored_string(text, color, mode, background)
+  if options.channel == 'tex' then
+    if mode == 'dim' then
+      mode = ''
+    end
+    return '\\textcolor{' ..
+      format.color_tex(color, mode) ..
+      '}{' ..
+      text ..
+      '}'
+  else
+   return template.color(color, mode, background) .. text .. template.color('reset')
+  end
+end
+
+--- Format a scaled point input value into dimension string (`12pt`,
+--  `1cm`)
+--
+-- @tparam number input
+--
+-- @treturn string
+function template.length (input)
+  input = tonumber(input)
+  input = input / tex.sp('1' .. options.unit)
+  return string.format(
+    '%g%s',
+    format.number(input),
+    template.colored_string(options.unit, 'white', 'dim')
+  )
+end
+
+--- Convert a Lua table into a format string.
+--
+-- @tparam table table A table to generate a inline view of.
+--
+-- @treturn string
+function template.table_inline(table)
+  local tex_escape = ''
+  if options.channel == 'tex' then
+    tex_escape = '\\'
+  end
+  if type(table) == 'table' then
+    local output = tex_escape .. '{'
+    local kv_list = ''
+    for key, value in pairs(table) do
+        if type(key) ~= 'numbers' then
+          key = '\'' ..
+            template.colored_string(key, 'cyan', 'dim') .. '\''
+        end
+        kv_list = kv_list .. '[' .. key .. '] = ' ..
+          template.table_inline(value) .. ', '
+    end
+    output = output .. kv_list:gsub(', $', '')
+    return output .. tex_escape .. '}'
+  else
+    return tostring(table)
+  end
+end
+
+--- Format a key value pair (`key: value, `).
+--
+-- @tparam string key A key
+-- @tparam string|number value A value
+-- @tparam string color A color name (`black`, `red`, `green`,
+--   `yellow`, `blue`, `magenta`, `cyan`, `white`).
+--
+-- @treturn string
+function template.key_value(key, value, color)
+  if type(color) ~= 'string' then
+    color = 'yellow'
+  end
+  if options.channel == 'tex' then
+    key = format.underscore(key)
+  end
+  local output = template.colored_string(key .. ':', color)
+  if value then
+    output = output .. ' ' .. value .. ', '
+  end
+  return output
+end
+
+---
+-- @treturn string
+function template.type(type, id)
+  local output
+  if options.channel == 'tex' then
+    output = format.underscore(type)
+  else
+    output = type
+  end
+  output = string.upper(output)
+  if options.verbosity > 1 then
+    output = output .. format.type_id(id)
+  end
+  return template.colored_string(
+    output .. format.whitespace(),
+    template.node_colors[type][1],
+    template.node_colors[type][2]
+  )
+end
+
+---
+-- @treturn string
+function template.callback(callback_name, variables)
+  nodetree_print(
+    format.new_line(2) ..
+    'Callback: ' ..
+    template.colored_string(format.underscore(callback_name), 'red', '', true) ..
+    format.new_line()
+  )
+  if variables then
+    for name, value in pairs(variables) do
+      if value ~= nil and value ~= '' then
+        nodetree_print(
+          '- ' ..
+          format.underscore(name) ..
+          ': ' ..
+          tostring(value) ..
+          format.new_line()
+        )
+      end
+    end
+  end
+  nodetree_print(template.line('long'))
+end
+
+---
+-- @treturn string
+function template.branches(level, connection_type)
+  local output = ''
+  for i = 1, level - 1  do
+    output = output .. template.branch('list', tree_state[i]['list'], false)
+    output = output .. template.branch('field', tree_state[i]['field'], false)
+  end
+-- Format the last branches
+  if connection_type == 'list' then
+    output = output .. template.branch('list', tree_state[level]['list'], true)
+  else
+    output = output .. template.branch('list', tree_state[level]['list'], false)
+    output = output .. template.branch('field', tree_state[level]['field'], true)
+  end
+  return output
+end
+
+--- Extend the node library
+-- @section node_extended
+
+local node_extended = {}
+
+--- Get the ID of a node.
+--
+-- We have to convert the node into a string and than have to extract
+-- the ID from this string using a regular expression. If you convert a
+-- node into a string it looks like: `<node    nil <    172 >    nil :
+-- hlist 2>`.
+--
+-- @tparam node n A node.
+--
+-- @treturn string
+function node_extended.node_id(n)
+  return string.gsub(tostring(n), '^<node%s+%S+%s+<%s+(%d+).*', '%1')
+end
+
+--- A table of all node subtype names.
+--
+-- __Nodes without subtypes:__
+--
+-- * `ins` (3)
+-- * `mark` (4)
+-- * `whatsit` (8)
+-- * `local_par` (9)
+-- * `dir` (10)
+-- * `penalty` (14)
+-- * `unset` (15)
+-- * `style` (16)
+-- * `choice` (17)
+-- * `fraction` (20)
+-- * `math_char` (23)
+-- * `sub_box` (24)
+-- * `sub_mlist` (25)
+-- * `math_text_char` (26)
+-- * `delim` (27)
+-- * `margin_kern` (28)
+-- * `align_record` (30)
+-- * `pseudo_file` (31)
+-- * `pseudo_line` (32)
+-- * `page_insert` (33)
+-- * `split_insert` (34)
+-- * `expr_stack` (35)
+-- * `nested_list` (36)
+-- * `span` (37)
+-- * `attribute` (38)
+-- * `glue_spec` (39)
+-- * `attribute_list` (40)
+-- * `temp` (41)
+-- * `align_stack` (42)
+-- * `movement_stack` (43)
+-- * `if_stack` (44)
+-- * `unhyphenated` (45)
+-- * `hyphenated` (46)
+-- * `delta` (47)
+-- * `passive` (48)
+-- * `shape` (49)
+--
+-- @treturn table
+local function get_node_subtypes ()
+    local subtypes = {
+    -- hlist (0)
+    hlist = {
+      [0] = 'unknown',
+      [1] = 'line',
+      [2] = 'box',
+      [3] = 'indent',
+      [4] = 'alignment',
+      [5] = 'cell',
+      [6] = 'equation',
+      [7] = 'equationnumber',
+      [8] = 'math',
+      [9] = 'mathchar',
+      [10] = 'hextensible',
+      [11] = 'vextensible',
+      [12] = 'hdelimiter',
+      [13] = 'vdelimiter',
+      [14] = 'overdelimiter',
+      [15] = 'underdelimiter',
+      [16] = 'numerator',
+      [17] = 'denominator',
+      [18] = 'limits',
+      [19] = 'fraction',
+      [20] = 'nucleus',
+      [21] = 'sup',
+      [22] = 'sub',
+      [23] = 'degree',
+      [24] = 'scripts',
+      [25] = 'over',
+      [26] = 'under',
+      [27] = 'accent',
+      [28] = 'radical',
+    },
+    -- vlist (1)
+    vlist = {
+      [0] = 'unknown',
+      [4] = 'alignment',
+      [5] = 'cell',
+    },
+    -- rule (2)
+    rule = {
+      [0] = 'normal',
+      [1] = 'box',
+      [2] = 'image',
+      [3] = 'empty',
+      [4] = 'user',
+      [5] = 'over',
+      [6] = 'under',
+      [7] = 'fraction',
+      [8] = 'radical',
+      [9] = 'outline',
+    },
+    -- adjust (5)
+    adjust = {
+      [0] = 'normal',
+      [1] = 'pre',
+    },
+    -- boundary (6)
+    boundary = {
+      [0] = 'cancel',
+      [1] = 'user',
+      [2] = 'protrusion',
+      [3] = 'word',
+    },
+    -- disc (7)
+    disc  = {
+      [0] = 'discretionary',
+      [1] = 'explicit',
+      [2] = 'automatic',
+      [3] = 'regular',
+      [4] = 'first',
+      [5] = 'second',
+    },
+    -- math (11)
+    math = {
+      [0] = 'beginmath',
+      [1] = 'endmath',
+    },
+    -- glue (12)
+    glue = {
+      [0]   = 'userskip',
+      [1]   = 'lineskip',
+      [2]   = 'baselineskip',
+      [3]   = 'parskip',
+      [4]   = 'abovedisplayskip',
+      [5]   = 'belowdisplayskip',
+      [6]   = 'abovedisplayshortskip',
+      [7]   = 'belowdisplayshortskip',
+      [8]   = 'leftskip',
+      [9]   = 'rightskip',
+      [10]  = 'topskip',
+      [11]  = 'splittopskip',
+      [12]  = 'tabskip',
+      [13]  = 'spaceskip',
+      [14]  = 'xspaceskip',
+      [15]  = 'parfillskip',
+      [16]  = 'mathskip',
+      [17]  = 'thinmuskip',
+      [18]  = 'medmuskip',
+      [19]  = 'thickmuskip',
+      [98]  = 'conditionalmathskip',
+      [99]  = 'muglue',
+      [100] = 'leaders',
+      [101] = 'cleaders',
+      [102] = 'xleaders',
+      [103] = 'gleaders',
+    },
+    -- kern (13)
+    kern = {
+      [0] = 'fontkern',
+      [1] = 'userkern',
+      [2] = 'accentkern',
+      [3] = 'italiccorrection',
+    },
+    -- penalty (14)
+    penalty = {
+      [0] = 'userpenalty',
+      [1] = 'linebreakpenalty',
+      [2] = 'linepenalty',
+      [3] = 'wordpenalty',
+      [4] = 'finalpenalty',
+      [5] = 'noadpenalty',
+      [6] = 'beforedisplaypenalty',
+      [7] = 'afterdisplaypenalty',
+      [8] = 'equationnumberpenalty',
+    },
+    noad = {
+      [0] = 'ord',
+      [1] = 'opdisplaylimits',
+      [2] = 'oplimits',
+      [3] = 'opnolimits',
+      [4] = 'bin',
+      [5] = 'rel',
+      [6] = 'open',
+      [7] = 'close',
+      [8] = 'punct',
+      [9] = 'inner',
+      [10] = 'under',
+      [11] = 'over',
+      [12] = 'vcenter',
+    },
+    -- radical (19)
+    radical = {
+      [0] = 'radical',
+      [1] = 'uradical',
+      [2] = 'uroot',
+      [3] = 'uunderdelimiter',
+      [4] = 'uoverdelimiter',
+      [5] = 'udelimiterunder',
+      [6] = 'udelimiterover',
+    },
+    -- accent (21)
+    accent = {
+      [0] = 'bothflexible',
+      [1] = 'fixedtop',
+      [2] = 'fixedbottom',
+      [3] = 'fixedboth',
+    },
+    -- fence (22)
+    fence = {
+      [0] = 'unset',
+      [1] = 'left',
+      [2] = 'middle',
+      [3] = 'right',
+      [4] = 'no',
+    },
+    -- margin_kern (28)
+    margin_kern = {
+      [0] = 'left',
+      [1] = 'right',
+    },
+    -- glyph (29)
+    glyph = {
+      [0] = 'character',
+      [1] = 'ligature',
+      [2] = 'ghost',
+      [3] = 'left',
+      [4] = 'right',
+    },
+  }
+  subtypes.whatsit = node.whatsits()
+  return subtypes
+end
+
+---
+-- @treturn string
+function node_extended.subtype(n)
+  local typ = node.type(n.id)
+  local subtypes = get_node_subtypes()
+
+  local output
+  if subtypes[typ] and subtypes[typ][n.subtype] then
+    output = subtypes[typ][n.subtype]
+    if options.verbosity > 1 then
+      output = output .. format.type_id(n.subtype)
+    end
+    return output
+  else
+    return tostring(n.subtype)
+  end
+end
+
+--- Build the node tree.
+-- @section tree
+
+local tree = {}
+
+---
+-- @tparam node head
+-- @tparam string field
+--
+-- @treturn string
+function tree.format_field(head, field)
+  local output
+-- Character "0" should be printed in a tree, because in TeX fonts the
+-- 0 slot usually has a symbol.
+  if not head[field] or (head[field] == 0 and field ~= "char") then
+    return ''
+  end
+
+  if options.verbosity < 2 and
+    -- glyph
+    field == 'font' or
+    field == 'left' or
+    field == 'right' or
+    field == 'uchyph' or
+    -- hlist
+    field == 'dir' or
+    field == 'glue_order' or
+    field == 'glue_sign' or
+    field == 'glue_set' or
+    -- glue
+    field == 'stretch_order' then
+    return ''
+  elseif options.verbosity < 3 and
+    field == 'prev' or
+    field == 'next' or
+    field == 'id'
+  then
+    return ''
+  end
+
+  if field == 'prev' or field == 'next' then
+    output = node_extended.node_id(head[field])
+  elseif field == 'subtype' then
+    output = format.underscore(node_extended.subtype(head))
+  elseif
+    field == 'width' or
+    field == 'height' or
+    field == 'depth' or
+    field == 'kern' or
+    field == 'shift' then
+    output = template.length(head[field])
+  elseif field == 'char' then
+    output = template.char(head[field])
+  elseif field == 'glue_set' then
+    output = format.number(head[field])
+  elseif field == 'stretch' or field == 'shrink' then
+    output = template.fill(head[field], head[field .. '_order'], field)
+  else
+    output = tostring(head[field])
+  end
+
+  return template.key_value(field, output)
+end
+
+---
+-- Attributes are key/value number pairs. They are printed as an inline
+-- list. The attribute `0` with the value `0` is skipped because this
+-- attribute is in every node by default.
+--
+-- @tparam node head
+--
+-- @treturn string
+function tree.format_attributes(head)
+  if not head then
+    return ''
+  end
+  local output = ''
+  local attr = head.next
+  while attr do
+    if attr.number ~= 0 or (attr.number == 0 and attr.value ~= 0) then
+      output = output .. tostring(attr.number) .. '=' .. tostring(attr.value) .. ' '
+    end
+    attr = attr.next
+  end
+  return output
+end
+
+---
+-- @tparam number level `level` is a integer beginning with 1.
+-- @tparam number connection_type The variable `connection_type`
+--   is a string, which can be either `list` or `field`.
+-- @tparam connection_state `connection_state` is a string, which can
+--   be either `continue` or `stop`.
+function tree.set_state(level, connection_type, connection_state)
+  if not tree_state[level] then
+    tree_state[level] = {}
+  end
+  tree_state[level][connection_type] = connection_state
+end
+
+---
+-- @tparam table fields
+-- @tparam number level
+function tree.analyze_fields(fields, level)
+  local max = 0
+  local connection_state
+  for _ in pairs(fields) do
+    max = max + 1
+  end
+  local count = 0
+  for field_name, recursion_node in pairs(fields) do
+    count = count + 1
+    if count == max then
+      connection_state = 'stop'
+    else
+      connection_state = 'continue'
+    end
+    tree.set_state(level, 'field', connection_state)
+    nodetree_print(
+      format.node_begin() ..
+      template.branches(level, 'field') ..
+      template.key_value(field_name) ..
+      format.node_end() ..
+      format.new_line()
+    )
+    tree.analyze_list(recursion_node, level + 1)
+  end
+end
+
+---
+-- @tparam node head
+-- @tparam number level
+function tree.analyze_node(head, level)
+  local connection_state
+  local output
+  if head.next then
+    connection_state = 'continue'
+  else
+    connection_state = 'stop'
+  end
+  tree.set_state(level, 'list', connection_state)
+  output = template.branches(level, 'list')
+    .. template.type(node.type(head.id), head.id)
+  if options.verbosity > 1 then
+    output = output .. template.key_value('no', node_extended.node_id(head))
+  end
+
+  -- We store the attributes output to append it to the field list.
+  local attributes
+
+  -- We store fields which are nodes for later treatment.
+  local fields = {}
+
+  -- Inline fields, for example: char: 'm', width: 25pt, height: 13.33pt,
+  local output_fields = ''
+  for _, field_name in pairs(node.fields(head.id, head.subtype)) do
+    if field_name == 'attr' then
+      attributes = tree.format_attributes(head.attr)
+    elseif field_name ~= 'next' and field_name ~= 'prev' and
+      node.is_node(head[field_name]) then
+      fields[field_name] = head[field_name]
+    else
+      output_fields = output_fields .. tree.format_field(head, field_name)
+    end
+  end
+  if output_fields ~= '' then
+    output = output .. output_fields
+  end
+
+  -- Append the attributes output if available
+  if attributes ~= '' then
+    output = output .. template.key_value('attr', attributes, 'blue')
+  end
+
+  output = output:gsub(', $', '')
+
+  nodetree_print(
+    format.node_begin() ..
+    output ..
+    format.node_end() ..
+    format.new_line()
+  )
+
+  local property = node.getproperty(head)
+  if property then
+    nodetree_print(
+      format.node_begin() ..
+      template.branches(level, 'field') ..
+      '  ' ..
+      template.colored_string('properties:', 'blue') .. ' ' ..
+      template.table_inline(property) ..
+      format.node_end() ..
+      format.new_line()
+    )
+  end
+
+  tree.analyze_fields(fields, level)
+end
+
+---
+-- @tparam node head
+-- @tparam number level
+function tree.analyze_list(head, level)
+  while head do
+    tree.analyze_node(head, level)
+    head = head.next
+  end
+end
+
+---
+-- @tparam node head
+function tree.analyze_callback(head)
+  tree.analyze_list(head, 1)
+  nodetree_print(template.line('short') .. format.new_line())
+end
+
+--- Callback wrapper.
+-- @section callbacks
+
+local callbacks = {
+
+  ---
+  -- @tparam string extrainfo
+  contribute_filter = function(extrainfo)
+    template.callback('contribute_filter', {extrainfo = extrainfo})
+    return true
+  end,
+
+  ---
+  -- @tparam string extrainfo
+  buildpage_filter = function(extrainfo)
+    template.callback('buildpage_filter', {extrainfo = extrainfo})
+    return true
+  end,
+
+  ---
+  -- @tparam string n
+  -- @tparam string i
+  build_page_insert = function(n, i)
+    print('lol')
+    template.callback('build_page_insert', {n = n, i = i})
+    return 0
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam string groupcode
+  pre_linebreak_filter = function(head, groupcode)
+    template.callback('pre_linebreak_filter', {groupcode = groupcode})
+    tree.analyze_callback(head)
+    return true
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam boolean is_display
+  linebreak_filter = function(head, is_display)
+    template.callback('linebreak_filter', {is_display = is_display})
+    tree.analyze_callback(head)
+    return true
+  end,
+
+  ---
+  -- @tparam node box
+  -- @tparam string locationcode
+  -- @tparam number prevdepth
+  -- @tparam boolean mirrored
+  append_to_vlist_filter = function(box, locationcode, prevdepth, mirrored)
+    local variables = {
+      locationcode = locationcode,
+      prevdepth = prevdepth,
+      mirrored = mirrored,
+    }
+    template.callback('append_to_vlist_filter', variables)
+    tree.analyze_callback(box)
+    return box
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam string groupcode
+  post_linebreak_filter = function(head, groupcode)
+    template.callback('post_linebreak_filter', {groupcode = groupcode})
+    tree.analyze_callback(head)
+    return true
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam string groupcode
+  -- @tparam number size
+  -- @tparam string packtype
+  -- @tparam string direction
+  -- @tparam node attributelist
+  hpack_filter = function(head, groupcode, size, packtype, direction, attributelist)
+    local variables = {
+      groupcode = groupcode,
+      size = size,
+      packtype = packtype,
+      direction = direction,
+      attributelist = attributelist,
+    }
+    template.callback('hpack_filter', variables)
+    tree.analyze_callback(head)
+    return true
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam string groupcode
+  -- @tparam number size
+  -- @tparam string packtype
+  -- @tparam number maxdepth
+  -- @tparam string direction
+  -- @tparam node attributelist
+  vpack_filter = function(head, groupcode, size, packtype, maxdepth, direction, attributelist)
+    local variables = {
+      groupcode = groupcode,
+      size = size,
+      packtype = packtype,
+      maxdepth = template.length(maxdepth),
+      direction = direction,
+      attributelist = attributelist,
+    }
+    template.callback('vpack_filter', variables)
+    tree.analyze_callback(head)
+    return true
+  end,
+
+  ---
+  -- @tparam string incident
+  -- @tparam number detail
+  -- @tparam node head
+  -- @tparam number first
+  -- @tparam number last
+  hpack_quality = function(incident, detail, head, first, last)
+    local variables = {
+      incident = incident,
+      detail = detail,
+      first = first,
+      last = last,
+    }
+    template.callback('hpack_quality', variables)
+    tree.analyze_callback(head)
+  end,
+
+  ---
+  -- @tparam string incident
+  -- @tparam number detail
+  -- @tparam node head
+  -- @tparam number first
+  -- @tparam number last
+  vpack_quality = function(incident, detail, head, first, last)
+    local variables = {
+      incident = incident,
+      detail = detail,
+      first = first,
+      last = last,
+    }
+    template.callback('vpack_quality', variables)
+    tree.analyze_callback(head)
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam number width
+  -- @tparam number height
+  process_rule = function(head, width, height)
+    local variables = {
+      width = width,
+      height = height,
+    }
+    template.callback('process_rule', variables)
+    tree.analyze_callback(head)
+    return true
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam string groupcode
+  -- @tparam number size
+  -- @tparam string packtype
+  -- @tparam number maxdepth
+  -- @tparam string direction
+  pre_output_filter = function(head, groupcode, size, packtype, maxdepth, direction)
+    local variables = {
+      groupcode = groupcode,
+      size = size,
+      packtype = packtype,
+      maxdepth = maxdepth,
+      direction = direction,
+    }
+    template.callback('pre_output_filter', variables)
+    tree.analyze_callback(head)
+    return true
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam node tail
+  hyphenate = function(head, tail)
+    template.callback('hyphenate')
+    nodetree_print('head:')
+    tree.analyze_callback(head)
+    nodetree_print('tail:')
+    tree.analyze_callback(tail)
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam node tail
+  ligaturing = function(head, tail)
+    template.callback('ligaturing')
+    nodetree_print('head:')
+    tree.analyze_callback(head)
+    nodetree_print('tail:')
+    tree.analyze_callback(tail)
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam node tail
+  kerning = function(head, tail)
+    template.callback('kerning')
+    nodetree_print('head:')
+    tree.analyze_callback(head)
+    nodetree_print('tail:')
+    tree.analyze_callback(tail)
+  end,
+
+  ---
+  -- @tparam node local_par
+  -- @tparam string location
+  insert_local_par = function(local_par, location)
+    template.callback('insert_local_par', {location = location})
+    tree.analyze_callback(local_par)
+    return true
+  end,
+
+  ---
+  -- @tparam node head
+  -- @tparam string display_type
+  -- @tparam boolean need_penalties
+  mlist_to_hlist = function(head, display_type, need_penalties)
+    local variables = {
+      display_type = display_type,
+      need_penalties = need_penalties,
+    }
+    template.callback('mlist_to_hlist', variables)
+    tree.analyze_callback(head)
+    return node.mlist_to_hlist(head, display_type, need_penalties)
+  end,
+}
+
+--- Set a single option key value pair.
+--
+-- @tparam string key The key of the option pair.
+-- @tparam number|string value The value of the option pair.
+local function set_option(key, value)
+  if not options then
+    options = {}
+  end
+  if key == 'verbosity' or key == 'decimalplaces' then
+    options[key] = tonumber(value)
+  else
+    options[key] = value
+  end
+end
+
+--- Set multiple key value pairs using a table.
+--
+-- @tparam table opts Options
+local function set_options(opts)
+  if not options then
+    options = {}
+  end
+  for key, value in pairs(opts) do
+    set_option(key, value)
+  end
+end
+
+--- Check if the given callback name exists.
+--
+-- Throw an error if it doen’t.
+--
+-- @tparam string callback_name The name of a callback to check.
+--
+-- @treturn string The unchanged input of the function.
+local function check_callback_name(callback_name)
+  local info = callback.list()
+  if info[callback_name] == nil then
+    tex.error(
+      'Package "nodetree": Unkown callback name or callback alias: "' ..
+      callback_name ..
+      '"'
+    )
+  end
+  return callback_name
+end
+
+--- Get the real callback name from an alias string.
+--
+-- @tparam string alias The alias of a callback name or the callback
+-- name itself.
+--
+-- @treturn string The real callback name.
+local function get_callback_name(alias)
+  local callback_name
+  -- Listed as in the LuaTeX reference manual.
+  if alias == 'contribute' or alias == 'contributefilter' then
+    callback_name = 'contribute_filter'
+
+  -- Formerly called buildpage, now there is a build_page_insert.
+  elseif alias == 'buildfilter' or alias == 'buildpagefilter' then
+    callback_name = 'buildpage_filter'
+
+  -- Untested: I don’t know how to invoke this filter.
+  elseif alias == 'buildinsert' or alias == 'buildpageinsert' then
+    callback_name = 'build_page_insert'
+
+  elseif alias == 'preline' or alias == 'prelinebreakfilter' then
+    callback_name = 'pre_linebreak_filter'
+
+  elseif alias == 'line' or alias == 'linebreakfilter' then
+    callback_name = 'linebreak_filter'
+
+  elseif alias == 'append' or alias == 'appendtovlistfilter' then
+    callback_name = 'append_to_vlist_filter'
+
+  -- postlinebreak is not documented.
+  elseif alias == 'postline' or alias == 'postlinebreak' or alias == 'postlinebreakfilter' then
+    callback_name = 'post_linebreak_filter'
+
+  elseif alias == 'hpack' or alias == 'hpackfilter' then
+    callback_name = 'hpack_filter'
+
+  elseif alias == 'vpack' or alias == 'vpackfilter' then
+    callback_name = 'vpack_filter'
+
+  elseif alias == 'hpackq' or alias == 'hpackquality' then
+    callback_name = 'hpack_quality'
+
+  elseif alias == 'vpackq' or alias == 'vpackquality' then
+    callback_name = 'vpack_quality'
+
+  elseif alias == 'process' or alias == 'processrule' then
+    callback_name = 'process_rule'
+
+  elseif alias == 'preout' or alias == 'preoutputfilter' then
+    callback_name = 'pre_output_filter'
+
+  elseif alias == 'hyph' or alias == 'hyphenate' then
+    callback_name = 'hyphenate'
+
+  elseif alias == 'liga' or alias == 'ligaturing' then
+    callback_name = 'ligaturing'
+
+  elseif alias == 'kern' or alias == 'kerning' then
+    callback_name = 'kerning'
+
+  elseif alias == 'insert' or alias == 'insertlocalpar' then
+    callback_name = 'insert_local_par'
+
+  elseif alias == 'mhlist' or alias == 'mlisttohlist' then
+    callback_name = 'mlist_to_hlist'
+
+  else
+    callback_name = alias
+  end
+  return check_callback_name(callback_name)
+end
+
+--- Register a callback.
+--
+-- @tparam string cb The name of a callback.
+local function register_callback(cb)
+  if options.engine == 'lualatex' then
+    luatexbase.add_to_callback(cb, callbacks[cb], 'nodetree')
+  else
+    callback.register(cb, callbacks[cb])
+  end
+end
+
+--- Unregister a callback.
+--
+-- @tparam string cb The name of a callback.
+local function unregister_callback(cb)
+  if options.engine == 'lualatex' then
+    luatexbase.remove_from_callback(cb, 'nodetree')
+  else
+    register_callback(cb, nil)
+  end
+end
+
+--- Exported functions.
+-- @section export
+
+local export = {
+  set_option = set_option,
+  set_options = set_options,
+
+  ---
+  register_callbacks = function()
+    if options.channel == 'log' or options.channel == 'tex' then
+      -- nt = nodetree
+      -- jobname.nttex
+      -- jobname.ntlog
+      local file_name = tex.jobname .. '.nt' .. options.channel
+      io.open(file_name, 'w'):close() -- Clear former content
+      output_file = io.open(file_name, 'a')
+    end
+    for alias in string.gmatch(options.callback, '([^,]+)') do
+      register_callback(get_callback_name(alias))
+    end
+  end,
+
+  ---
+  unregister_callbacks = function()
+    for alias in string.gmatch(options.callback, '([^,]+)') do
+      unregister_callback(get_callback_name(alias))
+    end
+  end,
+
+  --- Compile a TeX snippet.
+  --
+  -- Write some TeX snippets into a temporary LaTeX file, compile this
+  -- file using `latexmk` and read the generated `*.nttex` file and
+  -- return its content.
+  --
+  -- @tparam string tex_markup
+  --
+  -- @treturn string
+  compile_include = function(tex_markup)
+    -- Generate a subfolder for all tempory files: _nodetree-jobname.
+    local parent_path = lfs.currentdir() .. '/' .. '_nodetree-' .. tex.jobname
+    lfs.mkdir(parent_path)
+
+    -- Generate the temporary LuaTeX or LuaLaTeX file.
+    example_counter = example_counter + 1
+    local filename_tex = example_counter .. '.tex'
+    local absolute_path_tex = parent_path .. '/' .. filename_tex
+    output_file = io.open(absolute_path_tex, 'w')
+
+    local format_option = function (key, value)
+      return '\\NodetreeSetOption[' .. key .. ']{' .. value .. '}' .. '\n'
+    end
+
+    -- Process the options
+    local options =
+      format_option('channel', 'tex') ..
+      format_option('verbosity', options.verbosity) ..
+      format_option('unit', options.unit) ..
+      format_option('decimalplaces', options.decimalplaces) ..
+      '\\NodetreeUnregisterCallback{post_linebreak_filter}'  .. '\n' ..
+      '\\NodetreeRegisterCallback{' .. options.callback .. '}'
+
+    local prefix = '%!TEX program = lualatex\n' ..
+                  '\\documentclass{article}\n' ..
+                  '\\usepackage{nodetree}\n' ..
+                  options .. '\n' ..
+                  '\\begin{document}\n'
+    local suffix = '\n\\end{document}'
+    output_file:write(prefix .. tex_markup .. suffix)
+    output_file:close()
+
+    -- Compile the temporary LuaTeX or LuaLaTeX file.
+    os.spawn({ 'latexmk', '-cd', '-pdflua', absolute_path_tex })
+    local include_file = assert(io.open(parent_path .. '/' .. example_counter .. '.nttex', 'rb'))
+    local include_content = include_file:read("*all")
+    include_file:close()
+    include_content = include_content:gsub('[\r\n]', '')
+    tex.print(include_content)
+  end,
+
+  --- Check for `--shell-escape`
+  --
+  check_shell_escape = function()
+    local info = status.list()
+    if info.shell_escape == 0 then
+      tex.error('Package "nodetree-embed": You have to use the --shell-escape option')
+    end
+  end,
+
+  --- Print a node tree.
+  ---
+  -- @tparam node head The head node of a node list.
+  -- @tparam table opts Options as a table.
+  print = function(head, opts)
+    if opts and type(opts) == 'table' then
+      set_options(opts)
+    end
+    nodetree_print(format.new_line())
+    tree.analyze_list(head, 1)
+  end,
+
+  --- Format a scaled point value into a formated string.
+  --
+  -- @tparam number sp A scaled point value
+  --
+  -- @treturn string
+  format_dim = function(sp)
+    return template.length(sp)
+  end,
+
+  --- Get a default option that is not changed.
+  -- @tparam string key The key of the option.
+  --
+  -- @treturn string|number|boolean
+  get_default_option = function(key)
+    return default_options[key]
+  end
+}
+
+--- Use export.print
+-- @tparam node head
+export.analyze = export.print
+
+return export
diff --git a/macros/luatex/generic/nodetree/nodetree.pdf b/macros/luatex/generic/nodetree/nodetree.pdf
index 0ea7228abe..c7cdf1d72c 100644
--- a/macros/luatex/generic/nodetree/nodetree.pdf
+++ b/macros/luatex/generic/nodetree/nodetree.pdf