+(defcustom read-quoted-char-radix 8
+ "*Radix for \\[quoted-insert] and other uses of `read-quoted-char'.
+Legitimate radix values are 8, 10 and 16."
+ :type '(choice (const 8) (const 10) (const 16))
+ :group 'editing-basics)
+
+(defun read-quoted-char (&optional prompt)
+ "Like `read-char', but do not allow quitting.
+Also, if the first character read is an octal digit,
+we read any number of octal digits and return the
+specified character code. Any nondigit terminates the sequence.
+If the terminator is RET, it is discarded;
+any other terminator is used itself as input.
+
+The optional argument PROMPT specifies a string to use to prompt the user.
+The variable `read-quoted-char-radix' controls which radix to use
+for numeric input."
+ (let ((message-log-max nil) done (first t) (code 0) translated)
+ (while (not done)
+ (let ((inhibit-quit first)
+ ;; Don't let C-h get the help message--only help function keys.
+ (help-char nil)
+ (help-form
+ "Type the special character you want to use,
+or the octal character code.
+RET terminates the character code and is discarded;
+any other non-digit terminates the character code and is then used as input."))
+ (setq translated (read-key (and prompt (format "%s-" prompt))))
+ (if inhibit-quit (setq quit-flag nil)))
+ (if (integerp translated)
+ (setq translated (char-resolve-modifiers translated)))
+ (cond ((null translated))
+ ((not (integerp translated))
+ (setq unread-command-events
+ (listify-key-sequence (this-single-command-raw-keys))
+ done t))
+ ((/= (logand translated ?\M-\^@) 0)
+ ;; Turn a meta-character into a character with the 0200 bit set.
+ (setq code (logior (logand translated (lognot ?\M-\^@)) 128)
+ done t))
+ ((and (<= ?0 translated)
+ (< translated (+ ?0 (min 10 read-quoted-char-radix))))
+ (setq code (+ (* code read-quoted-char-radix) (- translated ?0)))
+ (and prompt (setq prompt (message "%s %c" prompt translated))))
+ ((and (<= ?a (downcase translated))
+ (< (downcase translated)
+ (+ ?a -10 (min 36 read-quoted-char-radix))))
+ (setq code (+ (* code read-quoted-char-radix)
+ (+ 10 (- (downcase translated) ?a))))
+ (and prompt (setq prompt (message "%s %c" prompt translated))))
+ ((and (not first) (eq translated ?\C-m))
+ (setq done t))
+ ((not first)
+ (setq unread-command-events
+ (listify-key-sequence (this-single-command-raw-keys))
+ done t))
+ (t (setq code translated
+ done t)))
+ (setq first nil))
+ code))
+