[latex3-commits] [git/LaTeX3-latex3-latex2e] gh239: Implement copying composites from a predefined list (81b00a7f)

[PhelypeOleinik]

Repository : https://github.com/latex3/latex2e
On branch  : gh239
Link       : https://github.com/latex3/latex2e/commit/81b00a7f142146520bd5febe64f244bbb0291075

>---------------------------------------------------------------

commit 81b00a7f142146520bd5febe64f244bbb0291075
Author: PhelypeOleinik <tex.phelype at gmail.com>
Date:   Thu Jun 11 20:16:13 2020 -0300

    Implement copying composites from a predefined list


>---------------------------------------------------------------

81b00a7f142146520bd5febe64f244bbb0291075
 base/ltoutenc.dtx | 93 ++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 82 insertions(+), 11 deletions(-)

diff --git a/base/ltoutenc.dtx b/base/ltoutenc.dtx
index a0d1daaf..75e06808 100644
--- a/base/ltoutenc.dtx
+++ b/base/ltoutenc.dtx
@@ -1241,6 +1241,10 @@
 % \begin{macro}{\@copy at declaretextcommand@enc}
 % \begin{macro}{\@copy at declaretextcommand@defaults}
 % \begin{macro}{\@unexpanded at cdrcar}
+% \begin{macro}{\@if at text@composite at copy@else}
+% \begin{macro}{\@copy at text@composite}
+% \begin{macro}{\@copy at one@composite}
+% \begin{macro}{\@copy at composite@stop}
 % \changes{v1.5h}{2020/05/09}{Added \cs{DeclareCommandCopy} (gh/239)}
 %
 %   With the generic \cs{NewCommandCopy} macro defined earlier in
@@ -1392,7 +1396,7 @@
     \ifx\reserved at a#5%
       \long\def#4{\UseTextAccent{#1}#2}%
     \else
-      \@if at text@composite at copy@else#4#5#3{#6}%
+      \@if at text@composite at copy@else#4#5{#6}%
         {\declare at command@copy at let#4#5}%
     \fi
   \fi}
@@ -1402,14 +1406,23 @@
 %   composite command.  Text composites are declared differently for
 %   each argument \meta{char}, and are stored as
 %   |\\|\meta{enc}|\|\meta{cmd}-\meta{char}, so we can't copy them
-%   unless we know every \meta{char} that was declared.  A copied
-%   composite will still work, but that's because it will use the old
-%   name, so it isn't a \emph{full} copy.
+%   unless we know every \meta{char} that was declared.  To completely
+%   copy a composite we define a list of characters used in composites
+%   for each encoding, and when copying we cycle through that list
+%   copying the command when defined.  \cs{@copy at text@composite} takes
+%   care of copying a composite.
 %    \begin{macrocode}
-\def\@if at text@composite at copy@else#1#2#3#4{%
+\def\@if at text@composite at copy@else#1#2#3{%
   \begingroup
     \escapechar=`\\
     \edef\x{\endgroup
+%    \end{macrocode}
+%
+%   Here we use the same approach as in \cs{@if at DeclareTextCommand}:
+%   define a temporary macro with a template text and then check if the
+%   macro we're copying matches.  Here's the macro that will make the
+%   test:
+%    \begin{macrocode}
   \def\noexpand\reserved at a####1\detokenize{%
     macro:}\string##1->%
       \detokenize{\@text at composite#2}\string##1\detokenize{\@empty
@@ -1419,16 +1432,70 @@
     \else
       \expandafter\@firstoftwo
     \fi}}%
+%    \end{macrocode}
+%
+%   And here we use it on \cs{meaning}\verb=#2=:
+%    \begin{macrocode}
   \noexpand\reserved at a\meaning#2\detokenize{%
     macro:}\string##1->%
       \detokenize{\@text at composite#2}\string##1\detokenize{\@empty
       \@text at composite}{\relax}\noexpand\@nil
-  }\x
-    {\@latex at error{Composites cannot be copied yet}\@eha%
-     \@firstofone
-     % \@copy at text@composite
-     }%
-    {\@firstofone}}
+%    \end{macrocode}
+%
+%   If the test is true, call \cs{@copy at text@composite} to do the
+%   copying (with \cs{lowercase} to get )
+%    \begin{macrocode}
+  }\x{\@copy at text@composite#1#2{#3}%
+      \@gobble}%
+     {\@firstofone}}
+%    \end{macrocode}
+%
+%   Copying the composite command is rather easy, as we can temporarily
+%   redefine \cs{@text at composite} to do the hard work for us.
+%    \begin{macrocode}
+\def\@copy at text@composite#1#2#3{%
+  \begingroup
+    \def\@text at composite##1##2\@text at composite##3{%
+  \endgroup
+  \def#1####1{\@text at composite#1##2\@text at composite{##3}}}%
+  #2{##1}%
+%    \end{macrocode}
+%
+%   Now expand the list of composites for the current (being copied)
+%   encoding (\verb=#3=) and call \cs{@copy at one@composite} with the new
+%   name, the old name, and one item in the list.
+%    \begin{macrocode}
+  \begingroup
+    \escapechar=`\\
+    \edef\x{\endgroup
+  \noexpand\@copy at one@composite
+    {\string#1}{\string#2}%
+    \ifx\csname @list@#3enc at composites\endcsname\relax
+      \unexpande{\@nnil\@nil
+        \@latex at error{List of composites undefined for encoding #3}\@ehc}
+    \else
+      \unexpanded\expandafter\expandafter
+        \expandafter{\csname @list@#3enc at composites\endcsname
+          \@nnil\@nil}%
+    \fi}%
+  \x}
+%    \end{macrocode}
+%
+%   To actually make the copy, use just \cs{ifcsname} as it prevents the
+%   csname from being added to the hash table, and makes the whole thing
+%   a bit faster, since it doesn't require the two test from
+%   \cs{@ifundefined} (as a side effect, commands that are equal to
+%   \cs{relax} are copied through, but then, it's unlikely).
+%    \begin{macrocode}
+\def\@copy at one@composite#1#2#3{%
+  \ifx\@nnil#3\@copy at composite@stop\fi
+  \ifcsname#2-\string#3\endcsname
+    \expandafter
+      \let\csname#1-\string#3\expandafter\endcsname
+          \csname#2-\string#3\endcsname
+  \fi
+  \@copy at one@composite{#1}{#2}}
+\def\@copy at composite@stop\fi#1\@copy at one@composite#2\@nil{\fi}
 %    \end{macrocode}
 %
 %   Here's the \cs{@copy at declaretextcommand@enc} auxiliary:
@@ -1465,6 +1532,10 @@
 % \end{macro}
 % \end{macro}
 % \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+% \end{macro}
 %
 % \subsubsection{Hyphenation}
 %