3 files changed, 66 insertions, 2 deletions

diff --git a/src/callint.c b/src/callint.c
index 2ff2f80d740..be0fb1a84df 100644
--- a/src/callint.c
+++ b/src/callint.c
@@ -511,6 +511,7 @@ invoke it.  If KEYS is omitted or nil, the return value of
   for (i = 2; *tem; i++)
     {
       visargs[1] = make_string (tem + 1, strcspn (tem + 1, "\n"));
+      visargs[1] = Finternal__text_restyle (visargs[1]);
       if (strchr (SSDATA (visargs[1]), '%'))
         callint_message = Fformat (i - 1, visargs + 1);
       else
diff --git a/src/doc.c b/src/doc.c
index f871ac75b59..3c8b11d73f3 100644
--- a/src/doc.c
+++ b/src/doc.c
@@ -1028,6 +1028,67 @@ Otherwise, return a new string.  */)
   xfree (buf);
   RETURN_UNGCPRO (tem);
 }
+
+DEFUN ("internal--text-restyle", Finternal__text_restyle,
+       Sinternal__text_restyle, 1, 1, 0,
+       doc: /* Return STRING, possibly substituting quote characters.
+
+In the result, replace each curved single quote (\\=‘ and \\=’) by
+left and right quote characters as specified by ‘text-quoting-style’.
+
+Return the original STRING in the common case where no changes are needed.
+Otherwise, return a new string.  */)
+  (Lisp_Object string)
+{
+  bool changed = false;
+
+  CHECK_STRING (string);
+  if (! STRING_MULTIBYTE (string))
+    return string;
+
+  enum text_quoting_style quoting_style = text_quoting_style ();
+  if (quoting_style == CURVE_QUOTING_STYLE)
+    return string;
+
+  ptrdiff_t bsize = SBYTES (string);
+  unsigned char const *strp = SDATA (string);
+  unsigned char const *strlim = strp + bsize;
+  USE_SAFE_ALLOCA;
+  char *buf = SAFE_ALLOCA (bsize);
+  char *bufp = buf;
+  ptrdiff_t nchars = 0;
+
+  while (strp < strlim)
+    {
+      unsigned char const *cp = strp;
+      switch (STRING_CHAR_ADVANCE (strp))
+        {
+        case LEFT_SINGLE_QUOTATION_MARK:
+          *bufp++ = quoting_style == GRAVE_QUOTING_STYLE ? '`': '\'';
+          changed = true;
+          break;
+
+        case RIGHT_SINGLE_QUOTATION_MARK:
+          *bufp++ = '\'';
+          changed = true;
+          break;
+
+        default:
+          do
+            *bufp++ = *cp++;
+          while (cp != strp);
+
+          break;
+        }
+
+      nchars++;
+    }
+
+  Lisp_Object result
+    = changed ? make_string_from_bytes (buf, nchars, bufp - buf) : string;
+  SAFE_FREE ();
+  return result;
+}
 
 void
 syms_of_doc (void)
@@ -1061,4 +1122,5 @@ displayable, and like ‘grave’ otherwise.  */);
   defsubr (&Sdocumentation_property);
   defsubr (&Ssnarf_documentation);
   defsubr (&Ssubstitute_command_keys);
+  defsubr (&Sinternal__text_restyle);
 }
diff --git a/src/editfns.c b/src/editfns.c
index 8ac0ef16999..da7d554fd94 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -3696,8 +3696,8 @@ usage: (message FORMAT-STRING &rest ARGS)  */)
     }
   else
     {
-      register Lisp_Object val;
-      val = Fformat (nargs, args);
+      args[0] = Finternal__text_restyle (args[0]);
+      Lisp_Object val = Fformat (nargs, args);
       message3 (val);
       return val;
     }
@@ -3722,6 +3722,7 @@ usage: (message-box FORMAT-STRING &rest ARGS)  */)
     }
   else
     {
+      args[0] = Finternal__text_restyle (args[0]);
       Lisp_Object val = Fformat (nargs, args);
       Lisp_Object pane, menu;
       struct gcpro gcpro1;