move rejected into per-package namespace

unicodedomino.sty

@@ -96,6 +96,17 @@
  \expandafter\UTFviii@defined\csname u8:#1\endcsname%
 }%
 
+% split an invalid byte sequence for error output
+\gdef\unicodedomino@splitseq#1:#2\relax{%
+ \unicodedomino@hexseq#2\relax%
+}%
+\gdef\unicodedomino@hexseq#1#2\relax{%
+ % display first octet
+ \space "\UTFviii@hexbyte{`#1}%
+ % recursively handle remaining octets
+ \ifx\relax#2\relax\else\unicodedomino@hexseq#2\relax\fi%
+}%
+
 % main handler
 \def\UTFviii@defined#1{%
  \ifx#1\relax%
@@ -112,7 +123,7 @@
   \else%
    % invalid multibyte character
    \PackageError{inputenc}{Invalid UTF-8 byte sequence:%
-    \expandafter\UTFviii@splitseq\string#1\relax}%
+    \expandafter\unicodedomino@splitseq\string#1\relax}%
     \UTFviii@invalid@help
   \fi%
  \else%

unicodedomino_kernel_better_decode.def

@@ -5,6 +5,7 @@
 %-
 % Improved Unicode decoding using the fixed-up checkseq code.
 
+%: entire file (plus UTFviii@checkseq) not submitted yet
 % override stock function, calling safer decode below
 \gdef\decode@UTFviii#1\relax{%
  \the\numexpr(\UTFviii@decode0:#1\relax)%

unicodedomino_kernel_cosmetics.def

@@ -20,8 +20,7 @@
  }%
 \fi%
 
-%: reverted partially, override bogus definition
-% format a number as Unicode codepoint hex
+% override to format a hex Unicode codepoint correctly
 \gdef\UTFviii@hexcodepoint#1{%
  \ifnum#1<16 U+000%
  \else\ifnum#1<256 U+00%
@@ -32,17 +31,3 @@
  \fi\fi\fi\fi\fi%
  \UTFviii@hexnumber{#1}%
 }%
-
-%: https://github.com/latex3/latex2e/pull/62 (rejected)
-% split an invalid byte sequence for output
-\ifx\UTFviii@splitseq\@undefined%
- \gdef\UTFviii@splitseq#1:#2\relax{%
-  \UTFviii@hexseq#2\relax%
- }%
- \gdef\UTFviii@hexseq#1#2\relax{%
-  % display first octet
-  \space "\UTFviii@hexbyte{`#1}%
-  % recursively handle remaining octets
-  \ifx\relax#2\relax\else\UTFviii@hexseq#2\relax\fi%
- }%
-\fi%