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}.%
}%