Add new user option 'translate-upper-case-key-bindings'

* doc/lispref/commands.texi (Key Sequence Input): Document it.

* lisp/cus-start.el (standard): defcustom it.

* src/keyboard.c (read_key_sequence): Use it.
(syms_of_keyboard): New variable 'translate-upper-case-key-bindings'.

diff --git a/doc/lispref/commands.texi b/doc/lispref/commands.texi
index 3425880fec5ff156cb9f99a5565c1037991ea0fb..8ad9df2522a21d4407f3b9554bb40cd83ccb78eb 100644 (file)
--- a/doc/lispref/commands.texi
+++ b/doc/lispref/commands.texi
@@ -2617,10 +2617,14 @@ returns the key sequence as a vector, never as a string.
 @cindex upper case key sequence
 @cindex downcasing in @code{lookup-key}
 @cindex shift-translation
+@vindex translate-upper-case-key-bindings
 If an input character is upper-case (or has the shift modifier) and
 has no key binding, but its lower-case equivalent has one, then
-@code{read-key-sequence} converts the character to lower case.  Note
-that @code{lookup-key} does not perform case conversion in this way.
+@code{read-key-sequence} converts the character to lower case.  (This
+behaviour can be disabled by setting the
+@code{translate-upper-case-key-bindings} user option to @code{nil}.)
+Note that @code{lookup-key} does not perform case conversion in this
+way.
 
 @vindex this-command-keys-shift-translated
 When reading input results in such a @dfn{shift-translation}, Emacs

diff --git a/etc/NEWS b/etc/NEWS
index 7deff1fa63f85cb241c1243524ab2698d6e9d167..b039310afa890d730e94957b08c68b658ccf706d 100644 (file)
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -51,6 +51,11 @@ These forms now indent like this:
 This change also affects 'cl-macrolet', 'cl-flet*' and
 'cl-symbol-macrolet'.
 
++++
+** New user option 'translate-upper-case-key-bindings'.
+This can be set to nil to inhibit translating upper case keys to lower
+case keys.
+
 \f
 * Changes in Specialized Modes and Packages in Emacs 29.1
 

diff --git a/lisp/cus-start.el b/lisp/cus-start.el
index 1a3e5682bbab053b2515387af9b5da0575a51950..a46107a6784cb08b72f6de1ea489e896d6689e30 100644 (file)
--- a/lisp/cus-start.el
+++ b/lisp/cus-start.el
@@ -386,7 +386,7 @@ Leaving \"Default\" unchecked is equivalent with specifying a default of
                                      (const :tag "When sent SIGUSR1" sigusr1)
                                      (const :tag "When sent SIGUSR2" sigusr2))
                              "24.1")
-
+             (translate-upper-case-key-bindings keyboard boolean "29.1")
              ;; This is not good news because it will use the wrong
              ;; version-specific directories when you upgrade.  We need
              ;; customization of the front of the list, maintaining the

diff --git a/src/keyboard.c b/src/keyboard.c
index bc6f97586dd3e8772069b757e432510794083bd6..4f3232dc46c12e012803d00a16f52c2c3c66d83e 100644 (file)
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -10168,7 +10168,8 @@ read_key_sequence (Lisp_Object *keybuf, Lisp_Object prompt,
         use the corresponding lower-case letter instead.  */
       if (NILP (current_binding)
          && /* indec.start >= t && fkey.start >= t && */ keytran.start >= t
-         && FIXNUMP (key))
+         && FIXNUMP (key)
+         && translate_upper_case_key_bindings)
        {
          Lisp_Object new_key;
          EMACS_INT k = XFIXNUM (key);
@@ -10220,12 +10221,14 @@ read_key_sequence (Lisp_Object *keybuf, Lisp_Object prompt,
          int modifiers
            = CONSP (breakdown) ? (XFIXNUM (XCAR (XCDR (breakdown)))) : 0;
 
-         if (modifiers & shift_modifier
-             /* Treat uppercase keys as shifted.  */
-             || (FIXNUMP (key)
-                 && (KEY_TO_CHAR (key)
-                     < XCHAR_TABLE (BVAR (current_buffer, downcase_table))->header.size)
-                 && uppercasep (KEY_TO_CHAR (key))))
+         if (translate_upper_case_key_bindings
+             && (modifiers & shift_modifier
+                 /* Treat uppercase keys as shifted.  */
+                 || (FIXNUMP (key)
+                     && (KEY_TO_CHAR (key)
+                         < XCHAR_TABLE (BVAR (current_buffer,
+                                              downcase_table))->header.size)
+                     && uppercasep (KEY_TO_CHAR (key)))))
            {
              Lisp_Object new_key
                = (modifiers & shift_modifier
@@ -12495,6 +12498,16 @@ If nil, Emacs crashes immediately in response to fatal signals.  */);
                Vwhile_no_input_ignore_events,
                doc: /* Ignored events from while-no-input.  */);
 
+  DEFVAR_BOOL ("translate-upper-case-key-bindings",
+               translate_upper_case_key_bindings,
+               doc: /* If non-nil, interpret upper case keys as lower case (when applicable).
+Emacs allows binding both upper and lower case key sequences to
+commands.  However, if there is a lower case key sequence bound to a
+command, and the user enters an upper case key sequence that is not
+bound to a command, Emacs will use the lower case binding.  Setting
+this variable to nil inhibits this behaviour.  */);
+  translate_upper_case_key_bindings = true;
+
   pdumper_do_now_and_after_load (syms_of_keyboard_for_pdumper);
 }