master 7785463c8e 1/5: Add new bidi-string-strip-control-characters function

[Lars Ingebrigtsen]

branch: master
commit 7785463c8edbd83e0a7a4c2fe5c233949aa570f2
Author: Lars Ingebrigtsen <larsi@gnus.org>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Add new bidi-string-strip-control-characters function
    
    * lisp/international/characters.el
    (bidi-string-strip-control-characters): New function.
---
 etc/NEWS                         | 4 ++++
 lisp/international/characters.el | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/etc/NEWS b/etc/NEWS
index 47dbfba9c0..ac3b1dccf9 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -960,6 +960,10 @@ The input must be encoded text.
 
 * Lisp Changes in Emacs 29.1
 
+** New function 'bidi-string-strip-control-characters'.
+This utility function is meant for displaying strings when it's
+essential that there's no bidirectional context.
+
 ---
 ** The Gnus range functions have been moved to a new library, range.el.
 All the old names have been made obsolete.
diff --git a/lisp/international/characters.el b/lisp/international/characters.el
index ce23e995c1..63ac455ea6 100644
--- a/lisp/international/characters.el
+++ b/lisp/international/characters.el
@@ -1541,6 +1541,12 @@ Setup `char-width-table' appropriate for non-CJK 
language environment."
     #x2069)                          ; ?\N{pop directional isolate}
   "List of bidirectional control characters.")
 
+(defun bidi-string-strip-control-characters (string)
+  "Strip bidi control characters from STRING and return the result."
+  (apply #'string (seq-filter (lambda (char)
+                                (not (memq char bidi-control-characters)))
+                              string)))
+
 (defun update-glyphless-char-display (&optional variable value)
   "Make the setting of `glyphless-char-display-control' take effect.
 This function updates the char-table `glyphless-char-display',