From 76e8411b59e57c8401ec73fa9660ba4d9a90ca4b Mon Sep 17 00:00:00 2001
From: Joseph Wright <joseph.wright@morningstar2.co.uk>
Date: Tue, 3 Dec 2019 08:45:49 +0000
Subject: [PATCH] Preserve catcode in case changing

As far as possible: most accent marks are
catcode-11 anyway as-standard.
---
 l3kernel/l3text.dtx  | 32 ++++++++++++++++----------------
 l3kernel/l3token.dtx |  2 +-
 2 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/l3kernel/l3text.dtx b/l3kernel/l3text.dtx
index 94a2360b70..31e2fbd0d5 100644
--- a/l3kernel/l3text.dtx
+++ b/l3kernel/l3text.dtx
@@ -1523,8 +1523,8 @@
           }
           {
             \char_generate:nn { "0069 } { \@@_char_catcode:N #4 }
-            \char_generate:nn { "0307 } { \char_value_catcode:n { "0307 } }
-            \char_generate:nn {#1} { \char_value_catcode:n {#1} }
+            \char_generate:nn { "0307 } { \@@_char_catcode:N #4 }
+            \char_generate:nn {#1} { \@@_char_catcode:N #4 }
             \@@_change_case_loop:nnw {#2} {#3}
           }
       }
@@ -1561,7 +1561,7 @@
                 { \int_compare_p:nNn { `#3 } = { "0303 } }
               }
           }
-          { \char_generate:nn { "0307 } { \char_value_catcode:n { "0307 } } }
+          { \char_generate:nn { "0307 } { \@@_char_catcode:N #3 } }
         \@@_change_case_loop:nnw {#1} {#2} #3
       }
   }
@@ -1672,9 +1672,9 @@
 % \end{macro}
 %
 % \begin{macro}[rEXP]{\@@_change_case_lower_tr:nnnN}
-% \begin{macro}[rEXP]{\@@_change_case_lower_tr:nnw}
-% \begin{macro}[rEXP]{\@@_change_case_lower_tr_aux:nnN}
-% \begin{macro}[rEXP]{\@@_change_case_lower_tr_aux:nnnNN}
+% \begin{macro}[rEXP]{\@@_change_case_lower_tr:nnNw}
+% \begin{macro}[rEXP]{\@@_change_case_lower_tr:nnN}
+% \begin{macro}[rEXP]{\@@_change_case_lower_tr:nnnNN}
 %   The Turkic languages need special treatment for dotted-i and dotless-i.
 %   The lower casing rule can be expressed in terms of searching first for
 %   either a dotless-I or a dotted-I. In the latter case the mapping is
@@ -1687,7 +1687,7 @@
     \cs_new:Npn \@@_change_case_lower_tr:nnnN #1#2#3#4
       {
         \int_compare:nNnTF { `#4 } = { "0049 }
-          { \@@_change_case_lower_tr:nnw {#1} {#3} }
+          { \@@_change_case_lower_tr:nnNw {#1} {#3} #4 }
           {
             \int_compare:nNnTF { `#4 } = { "0130 }
               {
@@ -1703,27 +1703,27 @@
 %   combination is found both the dotless-I and the dot-above char have to
 %   be removed from the input.
 %    \begin{macrocode}
-    \cs_new:Npn \@@_change_case_lower_tr:nnw #1#2#3 \q_recursion_stop
+    \cs_new:Npn \@@_change_case_lower_tr:nnNw #1#2#3#4 \q_recursion_stop
       {
-        \tl_if_head_is_N_type:nTF {#3}
-          { \@@_change_case_lower_tr_aux:nnN }
+        \tl_if_head_is_N_type:nTF {#4}
+          { \@@_change_case_lower_tr:nnN }
           {
-            \char_generate:nn { "0131 } { \char_value_catcode:n { "0049 } }
+            \char_generate:nn { "0131 } { \@@_char_catcode:N #3 }
             \@@_change_case_loop:nnw
           }
-            {#1} {#2} #3 \q_recursion_stop
+            {#1} {#2} #4 \q_recursion_stop
       }
-    \cs_new:Npn \@@_change_case_lower_tr_aux:nnN #1#2#3
+    \cs_new:Npn \@@_change_case_lower_tr:nnN #1#2#3
       {
         \bool_lazy_or:nnTF
           { \token_if_cs_p:N #3 }
           { ! \int_compare_p:nNn { `#3 } = { "0307 } }
           {
-            \char_generate:nn { "0131 } { \char_value_catcode:n { "0130 } }
+            \char_generate:nn { "0131 } { \@@_char_catcode:N #3 }
             \@@_change_case_loop:nnw {#1} {#2} #3
           }
           {
-            \char_generate:nn { "0069 } { \char_value_catcode:n { "0130 } }
+            \char_generate:nn { "0069 } { \@@_char_catcode:N #3 }
             \@@_change_case_loop:nnw {#1} {#2}
           }
       }
@@ -1779,7 +1779,7 @@
           { \sys_if_engine_xetex_p: }
           {
             \exp_not:N \char_generate:nn { "0130 }
-              { \exp_not:N \char_value_catcode:n { "0069 } }
+              { \exp_not:N \@@_char_catcode:N #4 }
           }
           {
             \exp_not:N \exp_not:V
diff --git a/l3kernel/l3token.dtx b/l3kernel/l3token.dtx
index 05e239c2da..d2f491b011 100644
--- a/l3kernel/l3token.dtx
+++ b/l3kernel/l3token.dtx
@@ -1877,7 +1877,7 @@
     \tl_if_blank:nF {#3}
       {
         \exp_args:Ne \@@_to_nfd:n
-          { \char_generate:nn { `#3 } { \char_value_catcode:n { `#3 } } }
+          { \char_generate:nn { `#3 } { \@@_change_case_catcode:N #1 } }
       }
   }
 %    \end{macrocode}