[latex3-commits] [git/LaTeX3-latex3-latex3] master: Fix interaction with babel (0689b2b12)

[Joseph Wright]

Repository : https://github.com/latex3/latex3
On branch  : master
Link       : https://github.com/latex3/latex3/commit/0689b2b1267f58b04c85d47173d0fdbb3462b5b2

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

commit 0689b2b1267f58b04c85d47173d0fdbb3462b5b2
Author: Joseph Wright <joseph.wright at morningstar2.co.uk>
Date:   Thu Feb 13 21:28:16 2020 +0000

    Fix interaction with babel


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

0689b2b1267f58b04c85d47173d0fdbb3462b5b2
 l3kernel/CHANGELOG.md    |  3 +++
 l3kernel/l3text-case.dtx | 29 ++++++++++++++++++-----------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/l3kernel/CHANGELOG.md b/l3kernel/CHANGELOG.md
index faf70d360..3c1fe7215 100644
--- a/l3kernel/CHANGELOG.md
+++ b/l3kernel/CHANGELOG.md
@@ -7,6 +7,9 @@ this project uses date-based 'snapshot' version identifiers.
 
 ## [Unreleased]
 
+### Fixed
+- Interaction with some `babel` languages at the start of the document
+
 ## [2020-02-13]
 
 ### Changed
diff --git a/l3kernel/l3text-case.dtx b/l3kernel/l3text-case.dtx
index 944c76da0..e385199c6 100644
--- a/l3kernel/l3text-case.dtx
+++ b/l3kernel/l3text-case.dtx
@@ -1455,22 +1455,29 @@
     \AtBeginDocument
       {
         \group_begin:
-          \cs_set_protected:Npn \@@_change_case_setup:NN #1#2
+          \cs_set_protected:Npn \@@_change_case_setup:Nn #1#2
             {
               \quark_if_recursion_tail_stop:N #1
-              \cs_if_exist:cF { c_@@_uppercase_ \token_to_str:N #1 _tl }
+              \tl_if_single_token:nT {#2}
                 {
-                  \tl_const:cn { c_@@_uppercase_ \token_to_str:N #1 _tl }
-                    { #2 }
+                  \cs_if_exist:cF
+                    { c_@@_uppercase_ \token_to_str:N #1 _tl }
+                    {
+                      \tl_const:cn
+                        { c_@@_uppercase_ \token_to_str:N #1 _tl }
+                        { #2 }
+                    }
+                  \cs_if_exist:cF
+                    { c_@@_lowercase_ \token_to_str:N #2 _tl }
+                    {
+                      \tl_const:cn
+                        { c_@@_lowercase_ \token_to_str:N #2 _tl }
+                        { #1 }
+                    }
                 }
-              \cs_if_exist:cF { c_@@_lowercase_ \token_to_str:N #2 _tl }
-                {
-                  \tl_const:cn { c_@@_lowercase_ \token_to_str:N #2 _tl }
-                    { #1 }
-                }
-              \@@_change_case_setup:NN
+              \@@_change_case_setup:Nn
             }
-          \exp_after:wN \@@_change_case_setup:NN \@uclclist
+          \exp_after:wN \@@_change_case_setup:Nn \@uclclist
           \q_recursion_tail ?
           \q_recursion_stop
         \group_end: