subtree-merge commit 8efe1a65 of git@github.com:mirabilos/tex-unicodedomino

(unicodedomino.sty version 1.0; the only difference to 1.1, which is
only one commit further, is that 1.1 also works on Debian jessie but
for that to work includes material from LaTeX base as convenience
copy, which we don’t need at Teckids and thus/also don’t want)

unicodedomino.sty

+% -*- mode: tex -*-
+%-
+% Copyright © 2017
+%	mirabilos <t.glaser@tarent.de>
+% with contributions by (among others)
+%	David Carlisle <http://tex.stackexchange.com/users/1090>
+%
+% Provided that these terms and disclaimer and all copyright notices
+% are retained or reproduced in an accompanying document, permission
+% is granted to deal in this work without restriction, including un‐
+% limited rights to use, publicly perform, distribute, sell, modify,
+% merge, give away, or sublicence.
+%
+% This work is provided “AS IS” and WITHOUT WARRANTY of any kind, to
+% the utmost extent permitted by applicable law, neither express nor
+% implied; without malicious intent or gross negligence. In no event
+% may a licensor, author or contributor be held liable for indirect,
+% direct, other damage, loss, or other issues arising in any way out
+% of dealing in the work, even if advised of the possibility of such
+% damage or existence of a defect, except proven that it results out
+% of said person’s immediate fault when using the work as intended.
+%-
+% Change UTF-8 input encoding to not error out, but substitute, upon
+% encountering characters not set up with newunicodechar.
+
+\NeedsTeXFormat{LaTeX2e}%
+\ProvidesPackage{unicodedomino}[2017/02/19 1.0 Domino for unknown codepoints]%
+\makeatletter%
+
+\ifx\numexpr\@undefined%
+ \PackageError{unicodedomino}{This package requires numexpr}%
+\fi%
+\ifx\UTFviii@defined\@undefined%
+ \PackageError{unicodedomino}{This package requires UTF-8 input encoding}%
+\fi%
+
+% nicer printing of codepoint hex numbers, not strictly necessary
+\def\unicodedomino@codepoint#1{%
+ \ifnum#1>65535%
+  U-000%
+ \else\ifnum#1>4095%
+  U+%
+ \else%
+  U+0%
+ \fi\fi%
+ \expandafter\UTFviii@hexnumber\expandafter{#1}%
+}%
+
+% override to beautify the output, not strictly necessary but requested
+\gdef\UTFviii@splitcsname#1:#2\relax{%
+ #2 (\expandafter\unicodedomino@codepoint\expandafter{%
+  \the\numexpr\decode@UTFviii#2\relax})%
+}%
+
+% render the actual domino piece
+\def\unicodedomino@box#1#2{%
+ \begingroup%
+ \fboxsep=.1em%
+ \fboxrule=.4pt%
+ \texttt{\fbox{\makebox[0pt][l]{\textsuperscript{#1}}\textsubscript{#2}}}%
+ \endgroup%
+}%
+
+% expand one hex nybble
+\def\unicodedomino@hex@ne#1{%
+ \ifnum#1>15 %
+  \expandafter\unicodedomino@hex@ne\expandafter{\the\numexpr(#1-8)/16\relax}%
+ \fi%
+ \UTFviii@hexdigit{\numexpr#1\ifnum#1>0-((#1-8)/16)*16\fi\relax}.%
+}%
+% expand all hex nybbles, zero-padded
+\def\unicodedomino@hex@ll#1{%
+ \ifnum#1<65536 0.\fi%
+ \ifnum#1<4096 0.\fi%
+ \expandafter\unicodedomino@hex@ne\expandafter{#1}%
+}%
+% call the appropriate box function
+\def\unicodedomino@hex@do#1.#2.#3.#4.#5.{%
+ \ifnum#1>0%
+  \unicodedomino@box{0#1#2}{#3#4#5}%
+ \else%
+  \unicodedomino@box{#2#3}{#4#5}%
+ \fi%
+}%
+% split nybbles and pass on
+\protected\def\unicodedomino@hex#1{%
+ \edef\temp{\expandafter\unicodedomino@hex@ll\expandafter{#1}}%
+ \expandafter\unicodedomino@hex@do\temp\relax%
+}%
+% split, decode and pass on
+\def\unicodedomino@decode#1:#2\relax{%
+ \expandafter\unicodedomino@hex\expandafter{%
+  \the\numexpr\decode@UTFviii#2\relax%
+ }%
+}%
+
+\def\UTFviii@defined#1{%
+ \ifx#1\relax%
+  % unknown char
+  \ifx\protect\@typeset@protect%
+   % not protected
+   \PackageWarning{inputenc}{%
+    Unicode\space char\space\expandafter\UTFviii@splitcsname\string#1\relax%
+    \space not\space set\space up\space for\space use\MessageBreak with\space%
+    LaTeX, replacing}%
+    \expandafter\unicodedomino@decode\string#1\relax%
+   \else%
+    % protected, just write the original character
+    \expandafter\@gobblefour\string#1%
+  \fi%
+ \else%
+  % known char, expand
+  \expandafter#1%
+ \fi%
+}%
+
+\makeatother%
+\endinput