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v21 EDMACRO-FORMAT-KEYS chokes and dies on Meta number prefixes


From: sand
Subject: v21 EDMACRO-FORMAT-KEYS chokes and dies on Meta number prefixes
Date: Sun, 3 Aug 2003 12:19:26 -0700

This is with GNU Emacs 21.3.2 (i386-pc-linux-gnu, X toolkit, Xaw3d
scroll bars) of 2003-04-24 on raven, modified by Debian.

Turn on DEBUG-ON-ERROR.

Start a keyboard macro:

    C-x (

Move the current line to the top of the window with the following key
sequence:

    M-0 C-l

End the keyboard macro:

    C-x )

Edit the last keyboard macro:

    C-x C-k C-x e

Emacs will generate the following error message:

    Debugger entered--Lisp error: (error "Invalid character: 037000000060, 
-134217680, 0xf8000030")
      concat("M-" [-134217680] " ")
      (prog1 (concat "M-" (edmacro-subseq rest-mac 0 i) " ") (callf 
edmacro-subseq rest-mac i))

Etc., etc.

Internally, LAST-KEYBOARD-MACRO stores this macro as a two-character,
two-byte string: \xb0\x0c.  This uses the special convention that bit
7 indicates the Meta modifier.  When EDMACRO-FORMAT-KEYS goes to work,
one of the first things it does is convert these special characters
into the "modern" integer format: \xb0 becomes -134217680 or
0xf8000030.  All further processing takes place with this format.

At the end, however, this has to get converted to a keysequence text
format for display, and EDMACRO-FORMAT-KEYS does this with:

    (concat "M-" (edmacro-subseq rest-mac 0 i) " ")

(EDMACRO-SUBSEQ returns a sequence of these integers from positions 0
to I.)  CONCAT is unable to deal with integers outside the range of
[0..255] and barfs.  This may have worked before, but the docs say
that Emacs 21 uses a new internal format for character encoding.

So some solutions, in order of preference, are:

  1. CONCAT, STRING and all the comparable functions get extended to
     support characters outside of [0..255].
  2. Emacs gets INTEGER-CHARACTER-CODE and CHARACTER-CODE-INTEGER
     functions that convert to and from the special string
     convention.
  3. We add the attatched patch to "edmacro.el", which undoes just
     this particular integer conversion.

Derek

--
Derek Upham
address@hidden

"Ha!  Your Leaping Tiger Kung Fu is no match for my Frightened Piglet style!"

------------------------------ cut here ------------------------------

diff -u /usr/share/emacs/21.3/lisp/edmacro.el /home/sand/edmacro.el
--- /usr/share/emacs/21.3/lisp/edmacro.el       2002-07-06 06:39:24.000000000 
-0700
+++ /home/sand/edmacro.el       2003-08-03 12:11:50.000000000 -0700
@@ -387,6 +387,20 @@
 
 ;;; Formatting a keyboard macro as human-readable text.
 
+(defun edmacro-sanitize-for-string (seq)
+  "Convert a sequence of integers into a sequence of characters.
+
+The resulting characters follow the usual Emacs conventions (control
+characters are really ASCII control characters; Meta flags are
+indicated by bit 7 being set.
+
+This function only works with sequences that EDMACRO-FORMAT-KEYS has
+converted from the original string representation to integers."
+  (loop for i below (length seq) do
+        (when (< (aref seq i) 0)
+          (setf (aref seq i) (logand (aref seq i) 127))))
+  seq)
+
 (defun edmacro-format-keys (macro &optional verbose)
   (setq macro (edmacro-fix-menu-commands macro))
   (let* ((maps (append (current-minor-mode-maps)
@@ -419,7 +433,10 @@
                         (while (memq (aref rest-mac i) (cdr mdigs))
                           (incf i))
                         (and (not (memq (aref rest-mac i) pkeys))
-                             (prog1 (concat "M-" (edmacro-subseq rest-mac 0 i) 
" ")
+                             (prog1 (concat "M-"
+                                             (edmacro-sanitize-for-string
+                                              (edmacro-subseq rest-mac 0 i))
+                                             " ")
                                (callf edmacro-subseq rest-mac i)))))
                  (and (eq (aref rest-mac 0) ?\C-u)
                       (eq (key-binding [?\C-u]) 'universal-argument)




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