[latex3-commits] [git/LaTeX3-latex3-latex3] master: Avoid loop with encoding commands in \text_purify:n (f60d96c9d)

[Joseph Wright]

Repository : https://github.com/latex3/latex3
On branch  : master
Link       : https://github.com/latex3/latex3/commit/f60d96c9d907c388d9fd2f77d696ef5c6ddd8e9f

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

commit f60d96c9d907c388d9fd2f77d696ef5c6ddd8e9f
Author: Joseph Wright <joseph.wright at morningstar2.co.uk>
Date:   Tue Jan 5 21:50:50 2021 +0000

    Avoid loop with encoding commands in \text_purify:n


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

f60d96c9d907c388d9fd2f77d696ef5c6ddd8e9f
 l3kernel/CHANGELOG.md      |  3 +++
 l3kernel/l3text-purify.dtx | 24 +++++++++++++++++++++---
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/l3kernel/CHANGELOG.md b/l3kernel/CHANGELOG.md
index 99b085f79..3f99c660b 100644
--- a/l3kernel/CHANGELOG.md
+++ b/l3kernel/CHANGELOG.md
@@ -7,6 +7,9 @@ this project uses date-based 'snapshot' version identifiers.
 
 ## [Unreleased]
 
+### Fixed
+- Handling of encoding-specfic commands in `\text_purify:n`
+
 ## [2021-01-01]
 
 ## [2020-12-19]
diff --git a/l3kernel/l3text-purify.dtx b/l3kernel/l3text-purify.dtx
index 2b2c5d132..de64513ba 100644
--- a/l3kernel/l3text-purify.dtx
+++ b/l3kernel/l3text-purify.dtx
@@ -94,7 +94,8 @@
 % \begin{macro}[EXP]{\@@_purify_math_cmd:Nn}
 % \begin{macro}[EXP]{\@@_purify_replace:N}
 % \begin{macro}[EXP]{\@@_purify_replace:n}
-% \begin{macro}[EXP]{\@@_purify_expand:N, \@@_purify_protect:N}
+% \begin{macro}[EXP]{\@@_purify_expand:N, \@@_purify_protect:N, \@@_purify_encoding:N}
+% \begin{macro}[EXP]{\@@_purify_encoding_escape:NN}
 %   As in the other parts of the module, we start off with a standard
 %   \enquote{action} loop, with expansion applied up-front.
 %    \begin{macrocode}
@@ -288,15 +289,31 @@
   {
     \str_if_eq:nnTF {#1} { \protect }
       { \@@_purify_protect:N }
+      { \@@_purify_encoding:N #1 }
+  }
+\cs_new:Npn \@@_purify_protect:N #1
+  {
+    \@@_if_recursion_tail_stop_do:Nn #1 { \@@_purify_end:w }
+    \@@_purify_loop:w
+  }
+%    \begin{macrocode}
+%   Handle encoding commands, as detailed for expansion.
+%    \end{macrocode}
+\cs_new:Npn \@@_purify_encoding:N #1
+  {
+    \bool_lazy_or:nnTF
+      { \cs_if_eq_p:NN #1 \@current at cmd }
+      { \cs_if_eq_p:NN #1 \@changed at cmd }
+      { \@@_purify_encoding_escape:NN }
       {
         \@@_if_expandable:NTF #1
           { \exp_after:wN \@@_purify_loop:w #1 }
           { \@@_purify_loop:w }
       }
   }
-\cs_new:Npn \@@_purify_protect:N #1
+\cs_new:Npn \@@_purify_encoding_escape:NN #1#2
   {
-    \@@_if_recursion_tail_stop_do:Nn #1 { \@@_purify_end:w }
+    \@@_purify_store:n {#1}
     \@@_purify_loop:w
   }
 %    \end{macrocode}
@@ -323,6 +340,7 @@
 % \end{macro}
 % \end{macro}
 % \end{macro}
+% \end{macro}
 %
 % \begin{macro}
 %   {