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path: root/graphics/emo/emo.dtx
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% \iffalse meta-comment
%
% emo: emoji for all (LaTeX engines)
% (C) Copyright 2023 by Robert Grimm
% Released under LPPL v1.3c or later
% <https://github.com/apparebit/emo>
%
% \fi
% ^^A ----------------------------------------------------------------------------------
% \iffalse
% The option with date and version below applies to both \Provides<Something>
% declarations; see https://tug.org/TUGboat/tb29-2/tb92pakin.pdf.
%<*scaffold>
\ProvidesFile{emo.dtx}
%</scaffold>
%<package>\NeedsTeXFormat{LaTeX2e}
%<package>\ProvidesPackage{emo}
%<*package>
    [2023/03/20 v0.1 emoji for all]
%</package>
% ======================================================================================
%<*scaffold>
\iffalse
%</scaffold>
%<*readme>
# Emo: emoji for all (LaTeX engines)

This package defines the `\emo{<emoji-name>}` macro for including color emoji in
a document no matter the input encoding or LaTeX engine. It uses the Noto color
emoji font if the engine supports doing so and falls back onto PDF graphics
otherwise. I wrote this package to use emoji in an academic paper subject to
[The ACM Publishing
System](https://authors.acm.org/proceedings/production-information/accepted-latex-packages),
which prohibits the use of most LaTeX packages but has only minimal support for
non-Latin scripts. ๐ŸŽ‰

When emo is used with the `extra` option, this package also defines the
`\lingchi` and `\YHWH` macros for ๅ‡Œ้ฒ and ื™ื”ื•ื”, respectively. Both macros
preserve a subsequent space as space, no backslash needed. When used with the
`index` option, this package also emits a raw index entry for each use of an
emoji into an emo index or `.edx` file.

To **extract files** embedded in [emo.dtx](emo.dtx) and also rebuild the
[documentation](emo.pdf), run `pdflatex emo.dtx`.

To **configure the emoji**, run `python3 config/emo.py` with appropriate
arguments. The [package documentation](emo.pdf) explains the configuration tool
in detail, but you may find the `-h` for help option sufficient to get started.

To **install this package**, place `emo.def`, `emo.sty`, `lingchi.otf`, and the
contents of the `emo-graphics` directory somewhere where LaTeX can find them. In
a pinch, your project directory will do just fine.


## Supported Emoji

By default, emo supports only a few emoji:

1๏ธโƒฃ โ˜ฃ๏ธ โš–๏ธ โœ”๏ธ ๐Ÿ‡ช๐Ÿ‡บ ๐ŸŒ ๐ŸŒ ๐Ÿ›๏ธ ๐Ÿ๏ธ ๐ŸŸ๏ธ ๐Ÿณ๏ธโ€๐ŸŒˆ ๐Ÿท๏ธ ๐Ÿ‘๏ธ ๐Ÿ‘ฅ ๐Ÿ’ฑ ๐Ÿ’พ ๐Ÿ“ ๐Ÿ“Ÿ ๐Ÿ” ๐Ÿ•ต๏ธ ๐Ÿ—‘๏ธ ๐Ÿ˜ก ๐Ÿ›‘ ๐Ÿค– ๐Ÿค ๐Ÿฆœ ๐Ÿง‘โ€โš–๏ธ ๐Ÿงป ๐Ÿงพ

Their names are keycap-one, biohazard, balance-scale, check-mark, eu, foggy,
globe-africa-europe, classical-building, desert-island, stadium, rainbow-flag,
label, eye, busts, currency-exchange, floppy-disk, triangular-ruler, pager,
loupe-left, detective, wastebasket, enraged-face, stop-sign, robot, handshake,
parrot, judge, roll-of-paper, and receipt.

The [package's documentation](emo.pdf) explains the underlying naming scheme and
also how to reconfigure which emoji are supported. The [emo.py](config/emo.py)
script takes care of the heavy lifting during reconfiguration, converting SVG
into PDF files and generating an updated `emo.def` file.


## Copyright and Licensing

This package combines code written in LaTeX and Python with Unicode data about
emoji as well as graphics and fonts derived from Google's Noto fonts. As a
result, a number of different licenses apply, all of which are [OSI
approved](https://opensource.org/licenses/) and non-copyleft:

  * This package's [LaTeX code](emo.dtx) is ยฉ Copyright 2023 by Robert Grimm and
    has been released under the [LPPL
    v1.3c](https://www.latex-project.org/lppl/lppl-1-3c/) or later.
  * The [emo.py](config/emo.py) configuration script also is ยฉ Copyright 2023 by
    Robert Grimm but has been released under the [Apache 2.0
    license](https://www.apache.org/licenses/LICENSE-2.0).
  * The [emoji-test.txt](config/emoji-test.txt) configuration file is a data
    file from [Unicode TR-51](https://unicode.org/reports/tr51/) and hence
    subject to the [Unicode License](https://www.unicode.org/license.txt).
  * The `lingchi.otf` font is a two-glyph subset of the serif traditional
    Chinese version of Google's [Noto
    fonts](https://github.com/notofonts/noto-cjk) and hence subject to the [SIL
    Open Font License v1.1](https://scripts.sil.org/ofl).
  * The PDF graphics in the `emo-graphics` directory are derived from the
    sources for [Noto's color emoji](https://github.com/googlefonts/noto-emoji)
    and hence subject to the Apache 2.0 license.

%</readme>
% --------------------------------------------------------------------------------------
%<*buildscript>
pdflatex emo.dtx
makeindex -s gind.ist -o emo.ind emo.idx
# makeindex -s gglo.ist -o emo.gls emo.glo  # For tracking changes
pdflatex emo.dtx
%</buildscript>
%<*scaffold>
\fi
% ======================================================================================
\begingroup
%</scaffold>
%<*install>
\input docstrip.tex
\keepsilent
\askforoverwritefalse
\preamble

emo: emoji for all (LaTeX engines)
(C) Copyright 2023 by Robert Grimm
Released under LPPL v1.3c or later
<https://github.com/apparebit/emo>

\endpreamble
\usedir{tex/latex/emo}
\generate{\file{\jobname.sty}{\from{\jobname.dtx}{package}}}
%</install>
% Don't stop processing the .dtx file; only stop processing the install file.
%<install>\endbatchfile
% --------------------------------------------------------------------------------------
%<*scaffold>
\usedir{source/latex/emo}
\generate{\file{\jobname.ins}{\from{\jobname.dtx}{install}}}
\nopreamble\nopostamble
\usedir{source/latex/emo}
\generate{\file{build.sh}{\from{\jobname.dtx}{buildscript}}}
\usedir{doc/latex/emo}
\generate{\file{README.md}{\from{\jobname.dtx}{readme}}}
\endgroup
%</scaffold>
% ======================================================================================
%<*driver>
\PassOptionsToPackage{utf8}{inputenc}
\documentclass{ltxdoc}
% Override the default \small, which looks odd with Inconsolata.
\renewcommand{\MacroFont}{\normalsize\ttfamily}
\usepackage[extra]{\jobname}
\usepackage{enumitem}
\usepackage{parskip}
\usepackage{inconsolata}

% Use BlackFoundry's Inria fonts; see <https://tug.org/FontCatalogue/inriaserifregular/>
\usepackage[T1]{fontenc}
\usepackage[lining]{InriaSerif}
\renewcommand*\oldstylenums[1]{{\fontfamily{InriaSerif-OsF}\selectfont #1}}
\let\oldnormalfont\normalfont
\def\normalfont{\oldnormalfont\mdseries}

\usepackage{hyperref}
\EnableCrossrefs
\CodelineIndex
\RecordChanges
\begin{document}
    \DocInput{\jobname.dtx}
\end{document}
%</driver>
% \fi
%
% \newlist{inlinenum}{enumerate*}{1}
% \setlist[inlinenum]{label=(\alph{inlinenumi})}
% \newenvironment{verbaish}{%
%     \ttfamily%
%     \obeylines%
%     \obeyspaces%
%     \vspace{\the\parskip}%
%     \setlength{\parskip}{0pt}%
%     \setlength{\parindent}{2em}%
% }{}
%
% \GetFileInfo{\jobname.dtx}
%
% \DoNotIndex{\{,\}}
% \DoNotIndex{\begingroup,\char,\csname,\def}
% \DoNotIndex{\else,\endcsname,\endgroup,\expandafter}
% \DoNotIndex{\fi,\ifcsname,\ifluatex,\index}
% \DoNotIndex{\newcommand,\newif,\newindex}
% \DoNotIndex{\relax,\string,\textbackslash,\textsf,\texttt}
%
% \title{emo: emoji for all\\(LaTeX engines)}
% \author{\href{https://apparebit.com}{Robert Grimm}}
% \date{Version \fileversion\ (\filedate)}
%
% \maketitle
%
% \begin{abstract}
% \noindent{}Emo implements the |\emo|\marg{emoji-name} command for including
% color emoji such as \emo{desert-island} or \emo{parrot} in your documents
% independent of input encoding or LaTeX engine. The implementation uses the
% Noto color emoji font if the engine supports it and includes PDF graphics
% otherwise. The latter are automatically derived from Noto's SVG sources, so
% the visual appearance is very similar. The source repository is at
% \url{https://github.com/apparebit/emo}. Emo may come in particularly handy
% when dealing with academic publishers that provide only minimal support for
% non-Latin scripts (cough,
% \href{https://authors.acm.org/proceedings/production-information/accepted-latex-packages}{ACM},
% cough).
% \end{abstract}
%
% \tableofcontents
%
%
% ^^A ==================================================================================
% \section{Installation}
%
% Installation of the emo package is fairly straightforward, though it does
% involve a lot more files than usual.
%
% \begin{enumerate}
% \item Start by extracting this package's files from |emo.dtx| by running:
% \begin{verbaish}
% \$ pdflatex emo.dtx
% \end{verbaish}
%
% \item Build the package documentation with indices by running:
% \begin{verbaish}
% \$ source build.sh
% \end{verbaish}
%
% \item If you want to reconfigure the supported emoji, see \S\ref{sec:config}
% below.
%
% \item Put the following files somewhere LaTeX can find them. While your current
% project's directory will do, emo's installation potentially comprises
% thousands of files. Hence it may be preferrable to adhere to the
% \href{https://en.wikibooks.org/wiki/LaTeX/Installing_Extra_Packages}{TeX
% Directory Structure}, with dedicated directories for the following files:
% \begin{enumerate}
% \item |emo.sty| with the package implementation;
% \item |emo.def| with the emoji table;
% \item |lingchi.otf| for |\lingchi|;
% \item \emph{all} PDF files in the |emo-graphics| directory.
% \end{enumerate}
% \end{enumerate}
%
% When running on the LuaLaTeX engine, the emo package also uses the Noto color
% emoji (|NotoColorEmoji.ttf|) and Linux Libertine (|LinLibertine_R.otf|) fonts,
% with the latter used for rendering |\YHWH| only. Neither file is included with
% emo's distribution, since both of them are distributed with major TeX
% distributions already. If they are not included with your LaTeX distribution,
% you can find them on CTAN. The |lingchi.otf| font distributed with emo is a
% two glyph subset of |NotoSerifTC-Regular.otf|, i.e., the serif traditional
% Chinese version of Noto.
%
%
% ^^A ==================================================================================
% \section{Usage}
%
% As usual, you declare your document's dependency on emo with
% |\usepackage{emo}|. In addition to the unadorned form, emo takes up to two
% options:
% \begin{description}
% \item[extra] Also define the |\lingchi| and |\YHWH| macros, which produce
%     \lingchi and \YHWH, respectively, and are documented below.
% \item[index] Create an emoji index tagged |emo| with the |.edx| extension for
%     the raw index and the |.end| extension for the processed index. This
%     option relies on the |index| package, generates the raw |.edx| file,
%     but does not build or use the processed index.
% \end{description}
%
% \DescribeMacro{\emo}
% An |\emo|\marg{emoji-name} invocation expands to the named emoji. For
% LuaLaTeX, it uses the Noto color emoji font. For all other engines, it uses
% PDF graphics. That way, |\emo{desert-island}| results in~\emo{desert-island}
% and |\emo{parrot}| results in~\emo{parrot}.
%
% Since LaTeX tends to produce a lot of command line noise about underfull boxes
% and loaded fonts, it's a easy to miss meaningful warnings. For that reason,
% |\emo| expands to an attention-seeking error message upon undefined emoji
% names. For example, |\emo{boo}| produces \emo{boo}.
%
%
% ^^A ----------------------------------------------------------------------------------
% \subsection{Emoji Names}
%
% With some exceptions, emo's names for emoji are automatically derived from
% their Unicode names, with letters converted to lowercase, punctuation such as
% commas, colons, quotes, and parentheses stripped, and interword spaces
% replaced by dashes. Furthermore, instead of the rather verbose
% |dark-skin-tone|, |medium-dark-skin-tone|, etc modifiers, emo
% uses the more succinct |darkest|, |darker|, |medium|, |lighter|, and
% |lightest|.
%
% For some emoji names, emo goes further by hard-coding shorter names. Those
% names are listed in Table~\ref{tab:special-names}.
%
% \begin{table}
% \caption{Exceptional emoji names}
% \label{tab:special-names}
% \small\vspace{1em}
% \begin{tabular}{ll}
% \textbf{Transformed Unicode Name} & \textbf{Emo Replacement Name} \\ \hline
% |a-button-blood-type| & |a-button| \\
% |ab-button-blood-type| & |ab-button| \\
% |b-button-blood-type| & |b-button| \\
% |o-button-blood-type| & |o-button| \\
% |bust-in-silhouette| & |bust| \\
% |busts-in-silhouette| & |busts| \\
% |flag-european-union| & |eu| \\
% |globe-showing-americas| & |globe-americas| \\
% |globe-showing-asia-australia| & |globe-asia-australia| \\
% |globe-showing-europe-africa| & |globe-africa-europe| \\
% |hear-no-evil-monkey| & |hear-no-evil| \\
% |index-pointing-at-the-viewer| & |index-pointing-at-viewer| \\
% |index-pointing-at-the-viewer-darkest| & |index-pointing-at-viewer-darkest| \\
% |index-pointing-at-the-viewer-darker| & |index-pointing-at-viewer-darker| \\
% |index-pointing-at-the-viewer-medium| & |index-pointing-at-viewer-medium| \\
% |index-pointing-at-the-viewer-lighter| & |index-pointing-at-viewer-lighter| \\
% |index-pointing-at-the-viewer-lightest| & |index-pointing-at-viewer-lightest| \\
% |keycap-*| & |keycap-star| \\
% |keycap-#| & |keycap-hash| \\
% |keycap-0| & |keycap-zero| \\
% |keycap-1| & |keycap-one| \\
% |keycap-2| & |keycap-two| \\
% |keycap-3| & |keycap-three| \\
% |keycap-4| & |keycap-four| \\
% |keycap-5| & |keycap-five| \\
% |keycap-6| & |keycap-six| \\
% |keycap-7| & |keycap-seven| \\
% |keycap-8| & |keycap-eight| \\
% |keycap-9| & |keycap-nine| \\
% |keycap-10| & |keycap-ten| \\
% |magnifying-glass-tilted-left| & |loupe-left| \\
% |magnifying-glass-tilted-right| & |loupe-right| \\
% |palm-down-hand| & |palm-down| \\
% |palm-down-hand-darkest| & |palm-down-darkest| \\
% |palm-down-hand-darker| & |palm-down-darker| \\
% |palm-down-hand-medium| & |palm-down-medium| \\
% |palm-down-hand-lighter| & |palm-down-lighter| \\
% |palm-down-hand-lightest| & |palm-down-lightest| \\
% |palm-up-hand| & |palm-up| \\
% |palm-up-hand-darkest| & |palm-up-darkest| \\
% |palm-up-hand-darker| & |palm-up-darker| \\
% |palm-up-hand-medium| & |palm-up-medium| \\
% |palm-up-hand-lighter| & |palm-up-lighter| \\
% |palm-up-hand-lightest| & |palm-up-lightest| \\
% |rolling-on-the-floor-laughing| & |rofl| \\
% |see-no-evil-monkey| & |see-no-evil| \\
% |speak-no-evil-monkey| & |speak-no-evil| \\
% \end{tabular}
% \end{table}
%
% Emo's |emo.def| contains the names and codepoints of all currently supported
% emoji. Its distribution also includes the |emoji-test.txt| file, which is part
% of \href{https://unicode.org/reports/tr51/}{Unicode TR-51} and contains the
% names and codepoints of all \emph{potentially} supported emoji, i.e., all
% emoji. It further organizes emoji into groups and subgroups, with the current
% (sub)group being the one named on the closest line above the emoji that starts
% with |# |(|sub|)|group:|. As described in the next section, the group and
% subgroup names can be used during configuration for concisely naming a large
% number of emoji.
%
%
% ^^A ----------------------------------------------------------------------------------
% \subsection{Extras}
%
% \DescribeMacro{\lingchi}
% \DescribeMacro{\YHWH}
% The |\lingchi| and |\YHWH| macros take no arguments and produce \lingchi and
% \YHWH, respectively. They are only available if emo is used with the
% \textsf{extra} option. The former renders the Chinese term for ``death by a
% thousand cuts.'' While originally an execution method, the term applies to
% surprisingly many software systems as well. The latter produces the
% Tetragrammaton, the Hebrew name for God. Observant Jews never utter what's
% written, not even in their thoughts, substituting Adonai (``My Lord''), Elohim
% (``God''), or HaShem (``The Name'') instead. In my mind, that nicely mirrors
% the very incomprehensibility of \YHWH. Both macros preserve a subsequent space
% as space, no backslash needed.
%
%
% ^^A ==================================================================================
% \section{Configuration}
% \label{sec:config}
%
% Emo's implementation is split over two files, |emo.sty| and |emo.def|. The
% former file defines the substance of the package, its options, its helper
% macros, and the user-visible |\emo|, |\lingchi|, and |\YHWH| macros. The
% latter file defines the table of supported emoji. For each such emoji, the
% table contains a command |\emo@emoji@|\meta{emoji-name} with the emoji's
% codepoints as value. |emo.sty| includes the table during loading and
% thereafter relies on it for validating emoji names and rendering emoji in
% LuaLaTeX. It may be possible to combine the two files into one, but that
% avoids at most a few disc reads and hence doesn't seem worth the trouble.
%
%
% \subsection{Update Configuration}
%
% Invoke |config/emo.py| to automatically reconfigure emo's supported emoji:
% \begin{verbaish}
% \$ python3 config/emo.py \meta{selector} \meta{selector} $\ldots$
% \end{verbaish}
%
% Each selector may be:
% \begin{itemize}
% \item The literal |ALL| (case-sensitive) for \emph{all} emoji.
% \item Name of a group in |emoji-test.txt| lowercased and with spaces replaced
%     by dashes and ampersand |&| replaced by an |and|; e.g.,
%     |travel-and-places|.
% \item Name of a group, a double colon |::|, and name of a subgroup, again
%     lowercased and with spaces replaced by dashes and |&| by an |and|; e.g.,
%     |travel-and-places::place-geographic|.
% \item The name of an emoji; e.g., |desert-island|.
% \end{itemize}
% For conjunctive group names, such as ``Smileys \& Emotion'' (|emoji-test.txt|)
% or ``smileys-and-emotion'' (|emo.py|), the configuration script also accepts
% either of the two nouns as a shortcut, e.g., ``smileys'' or ``emotion.''
%
% For data safety, |emo.py| does not overwrite PDF graphics and hence can only
% add emoji to the configuration. To remove emoji, simply remove their PDF
% graphics from |emo-graphics| and then run |emo.py|, which updates the emoji
% table accordingly.
%
% |emo.py| effectively treats |emoji-test.txt| as registry of all emoji and the
% filenames of PDF graphics in |emo-graphics| as emo's current inventory. For
% all emoji named by selector arguments but not in the inventory, |emo.py|
% converts the SVG source graphic from the Noto color emoji sources to a PDF
% file and deletes the |/Page| |/Group| object from the the PDF again, since
% that object trips up |pdflatex|. And yeah, |emo.py| automatically downloads
% the Noto color emoji sources if necessary.
%
%
% ^^A ==================================================================================
% \section{Copyright and Licensing}
%
% Since emo's distribution includes not only LaTeX code but also a substantial
% Python script, Unicode data about emoji, as well as graphics and fonts derived
% from Google's Noto project, a number of different licenses apply. All of them
% are \href{https://opensource.org/licenses/}{OSI approved} and non-copyleft:
% \begin{itemize}
% \item This package's LaTeX code is ยฉ Copyright 2023 by Robert Grimm and has
%     been released under the
%     \href{https://www.latex-project.org/lppl/lppl-1-3c/}{LPPL v1.3c} or later.
% \item The |config/emo.py| script also is ยฉ Copyright 2023 by Robert Grimm but
%     has been released under the
%     \href{https://www.apache.org/licenses/LICENSE-2.0}{Apache 2.0 license}.
% \item The [config/emoji-test.txt] configuration file is a data file from
%     \href{https://unicode.org/reports/tr51/}{Unicode TR-51} and hence subject
%     to the \href{https://www.unicode.org/license.txt}{Unicode License}.
% \item The |lingchi.otf| font is a two-glyph subset of the serif traditional
%     Chinese version of Google's
%     \href{https://github.com/notofonts/noto-cjk}{Noto fonts} and hence subject
%     to the \href{https://scripts.sil.org/ofl}{SIL Open Font License v1.1}.
% \item The PDF graphics in the |emo-graphics| directory are derived from the
%     sources for \href{https://github.com/googlefonts/noto-emoji}{Noto's color
%     emoji} and hence subject to the Apache 2.0 license.
% \end{itemize}
%
%
% \StopEventually{\PrintIndex}
%
%
% ^^A ==================================================================================
% \section{Implementation}
%
% Now that we understand how to configure emo, we are ready for exploring the
% implementation in detail. Let's get started:
%    \begin{macrocode}
%<*package>
%    \end{macrocode}
%
% Except, the package implementation started near the top of the |emo.dtx| file,
% so that version number and date are more visible and declared only once. But
% that's also well before the documentation preamble and hence cannot be
% included in the annotated implementation. Nonetheless, we can simulate the
% lines:
%
% \begingroup\obeylines
% |\NeedsTeXFormat{LaTeX2e}|\setlength{\parskip}{0pt}
% |\ProvidesPackage{emo}[|\texttt{\filedate}| |\texttt{\fileversion}| emo for all]|
% \endgroup
%
% And no, I didn't repeat the version number and date. Check |emo.dtx|.
%
%
% ^^A ----------------------------------------------------------------------------------
% \subsection{Package Options}
%
% Emo's \textsf{extra} and \textsf{index} options are simple flags. So, we
% declare a |\newif| for each option and, if the package use includes an option,
% it just toggles the conditional's state:
%    \begin{macrocode}
\newif\ifemo@extra\emo@extrafalse
\DeclareOption{extra}{\emo@extratrue}
\newif\ifemo@indexing\emo@indexingfalse
\DeclareOption{index}{\emo@indexingtrue}
\ProcessOptions\relax
%    \end{macrocode}
%
%
% ^^A ----------------------------------------------------------------------------------
% \subsection{Dependencies}
%
% The dependency on |inputenc| effectively declares this file's encoding to be
% UTF-8. The XeTeX and LuaTeX engines already expect files to be encoded that
% way and hence ignore the declaration. However, pdfTeX supports other (legacy)
% encodings and needs to be told.
%    \begin{macrocode}
\RequirePackage[utf8]{inputenc}
%    \end{macrocode}
%
% Depending on TeX engine, this package requires either |fontspec| or |graphicx|
% as the emoji-emitting backend. In turn, to tell the engines apart, it requires
% |iftex|.
%    \begin{macrocode}
\RequirePackage{iftex}
\ifluatex
\RequirePackage{fontspec}
\else
\RequirePackage{graphicx}
\fi
%    \end{macrocode}
%
% Emo requires |xcolor| for formatting highly visible error messages within the
% text. Always including another package that is only used when there are errors
% is not ideal. But when I tried calling |\RequirePackage| for |xcolor| from
% inside the error macro, it didn't work. Alternatively, I could make in-text
% errors optional.
%    \begin{macrocode}
\RequirePackage{xcolor}
%    \end{macrocode}
%
% Finally, emo's options also have dependencies, with \textsf{extra} requiring
% the |xspace| package and \textsf{index} requiring the |index| package:
%    \begin{macrocode}
\ifemo@extra
\RequirePackage{xspace}
\fi
\ifemo@indexing
\RequirePackage{index}
\fi
%    \end{macrocode}
%
%
% ^^A ----------------------------------------------------------------------------------
% \subsection{The Emoji Table}
%
% For each emoji with a PDF graphic in the |emo-graphics| directory, a macro
% named |\emo@emoji@|\meta{emoji-name} expands to its Unicode sequence. With
% over 3,000 distinct emoji in Unicode 15, emo relies on a Python script for
% populating the graphics directory and writing the table to the
% \texttt{\jobname.def} file. Since the package code does not change after
% installation but the emoji table may very well change, they are kept separate
% for now. Alternatively, we could use DocStrip to assemble the package file
% from three parts, the code from the previous sections, then the contents of
% the emoji table in |emo.def|, and then all subsequent code.
%    \begin{macrocode}
\input{emo.def}
%    \end{macrocode}
%
%
% ^^A ----------------------------------------------------------------------------------
% \subsection{Internal Macros}
%
% \begin{macro}{emo@error@fg}
% \begin{macro}{emo@error@bg}
% \begin{macro}{emo@error}
% Define two colors and a function that uses the two colors for formatting an
% attention-grabbing error message. If you use an invalid emoji name and
% overlook the warning in the console, you \emph{will} notice the error messsage
% in the document thusly formatted.
%    \begin{macrocode}
\definecolor{emo@error@fg}{rgb}{1,1,1}
\definecolor{emo@error@bg}{rgb}{.6824,.0863,.0863}
\def\emo@error#1{%
    \colorbox{emo@error@bg}{%
        \textcolor{emo@error@fg}{%
            \textsf{Bad} \texttt{\textbackslash emo\{#1\}}%
        }%
    }%
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{emo@ifdef}
% Validate the emoji name given as first argument. The macro expands to the
% second argument if the name is valid and an error message otherwise. Its
% implementation relies on the |emo@emoji| table.
%    \begin{macrocode}
\def\emo@ifdef#1#2{%
    \ifcsname emo@emoji@#1\endcsname#2\else%
        \PackageWarning{emo}{Unknown emoji name in `\string\emo{#1}'}%
        \emo@error{#1}%
    \fi%
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{emo@index}
% If indexing is enabled, record the use of an emoji. Otherwise, do nothing.
%    \begin{macrocode}
\ifemo@indexing
\newindex{emo}{edx}{end}{Emoji Index}
\def\emo@index#1{\index[emo]{#1}}
\else
\def\emo@index#1{}
\fi
%    \end{macrocode}
% \end{macro}
%
%
% ^^A ----------------------------------------------------------------------------------
% \subsection{User Macros}
%
% \begin{macro}{emo}
% Emit the named color emoji. Both the font-based version for LuaTeX and the
% graphics-based fallback validate the emoji name and then invoke the
% |\emo@index| macro. But they differ in how they actually display the emoji.
% The LuaTeX version turns the emoji name into its Unicode sequence and wraps
% that in a group that also uses the previously declared Noto color emoji font.
% The fallback version instead includes a suitably sized PDF graphic.
%    \begin{macrocode}
\ifluatex
\newfontface\emo@font[Renderer=Harfbuzz]{NotoColorEmoji.ttf}
\newcommand\emo[1]{%
    \emo@ifdef{#1}{%
        \emo@index{#1}%
        {\emo@font\csname emo@emoji@#1\endcsname}%
    }%
}
\else
\newcommand\emo[1]{%
    \emo@ifdef{#1}{%
        \emo@index{#1}%
        \raisebox{-0.2ex}{\includegraphics[height=1em]{./emo-graphics/#1}}%
    }%
}
\fi
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{lingchi}
% \begin{macro}{YHWH}
% The definitions for the optional |\lingchi| and |\YHWH| macros follow from
% that of |\emo|, except that
% \begin{inlinenum}
% \item there are no arguments to validate and hence no equivalent to
%     |\emo@ifdef|;
% \item Hebrew is written right-to-left and hence |\YHWH| requires a
%     |\textdir TRT|;
% \item subsequent space should be preserved and hence both macros end
%     with |\xspace|.
% \end{inlinenum}
% While it would be nice to use Unicode inside the groups for the LuaTeX macros,
% doing so breaks the package documentation. So |\char| it is.
%    \begin{macrocode}
\ifemo@extra
\ifluatex
\newfontface\emo@chinese{lingchi.otf}
\newfontface\emo@hebrew{LinLibertine_R.otf}
\newcommand\lingchi{%
    \emo@index{lingchi}%
    \begingroup\emo@chinese \char"51CC\char"9072\endgroup%
    \xspace}
\newcommand\YHWH{%
    \emo@index{YHWH}%
    \begingroup\textdir TRT\emo@hebrew \char"5D9\char"5D4\char"5D5\char"5D4\endgroup%
    \xspace}
\else
\newcommand\lingchi{%
    \emo@index{lingchi}%
    \raisebox{-0.2ex}{\includegraphics[height=1em]{./emo-graphics/lingchi}}%
    \xspace}
\newcommand\YHWH{%
    \emo@index{YHWH}%
    \raisebox{-0.2ex}{\includegraphics[height=1em]{./emo-graphics/YHWH}}%
    \xspace}
\fi
\fi
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% Et voil\`a. That's it!
%
%    \begin{macrocode}
%</package>
%    \end{macrocode}
%
% \Finale
%
% ^^A ----------------------------------------------------------------------------------
% \obeyspaces
% \typeout{}
% \typeout{โ•”โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•emoโ•โ•โŠฐ}
% \typeout{โ•‘}
% \typeout{โ•‘ To extract build.sh, emo.ins, emo.sty, and README.md, run:}
% \typeout{โ•‘}
% \typeout{โ•‘     $ pdflatex emo.dtx}
% \typeout{โ•‘}
% \typeout{โ•‘}
% \typeout{โ•‘ To build emo's documentation with indices, run:}
% \typeout{โ•‘}
% \typeout{โ•‘     $ source build.sh}
% \typeout{โ•‘}
% \typeout{โ•‘}
% \typeout{โ•‘ To reconfigure supported emoji, run:}
% \typeout{โ•‘}
% \typeout{โ•‘     $ python3 config/emo.py -h}
% \typeout{โ•‘}
% \typeout{โ•‘}
% \typeout{โ•‘ To install emo, put these files somewhere LaTeX can find them:}
% \typeout{โ•‘}
% \typeout{โ•‘     emo.def}
% \typeout{โ•‘     emo.sty}
% \typeout{โ•‘     NotoSerifTC-Regular.otf}
% \typeout{โ•‘     emo-graphics/*.pdf}
% \typeout{โ•‘}
% \typeout{โ•šโ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•โ•emoโ•โ•โŠฐ}
% \typeout{}