GNU bug report logs - #6490
24.0.50; src/lread.c: old style backquote bug?

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Tetsurou Okazaki <okazaki <at> be.to>
To: bug-gnu-emacs <at> gnu.org
Cc: okazaki <at> be.to
Subject: 24.0.50; src/lread.c: old style backquote bug?
Date: Tue, 22 Jun 2010 18:16:56 +0900

[Message part 1 (text/plain, inline)]

The latest Bazaar version of Emacs fails to build APEL
[http://www.kanji.zinbun.kyoto-u.ac.jp/~tomo/elisp/APEL/index.en.html]
with the following message:

  % cvs -z9 -d :pserver:anonymous <at> cvs.m17n.org:/cvs/root checkout apel
  % cd apel
  % make

    emacs -batch -q -no-site-file -l APEL-MK -f compile-apel \
		  NONE NONE NONE
  Loading /home/tetsurou/Checkout/cvs.m17n.org/apel/APEL-CFG...
  Loading `product': old-style backquotes detected!
  Invalid function: (progn (\, product-def) (put (\, feature) (quote product) (let ((product (product-find-by-name (\, product-name)))) (product-run-checkers product (quote (\, product-version))) (and (\, product-family) (product-add-to-family (\, product-family) (\, product-name))) (product-add-feature product (\, feature)) (if (equal (quote (\, product-version)) (product-version product)) product (vector (\, product-name) (\, product-family) (quote (\, product-version)) (\, product-code-name) nil nil nil (\, product-version-string))))) (\, feature-def))
  make: *** [elc] Error 255

Attached patch for Emacs fixes this error.


In GNU Emacs 24.0.50.1 (i686-pc-cygwin, X toolkit, Xaw3d scroll bars)
 of 2010-06-18 on zeroset
configured using `configure  '--without-dbus' '--with-x-toolkit=athena''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: C
  value of $LANG: ja_JP.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  global-semanticdb-minor-mode: t
  global-semantic-idle-scheduler-mode: t
  semantic-mode: t
  global-ede-mode: t
  display-time-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
ESC x r e p o r TAB RET

Recent messages:
("emacs")
Loading term/xterm...done
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
/usr/local/share/emacs/site-lisp/flim/sha1 hides /usr/local/share/emacs/24.0.50/lisp/sha1
/usr/local/share/emacs/site-lisp/semi/pgg hides /usr/local/share/emacs/24.0.50/lisp/pgg
/usr/local/share/emacs/site-lisp/semi/pgg-pgp5 hides /usr/local/share/emacs/24.0.50/lisp/pgg-pgp5
/usr/local/share/emacs/site-lisp/semi/pgg-pgp hides /usr/local/share/emacs/24.0.50/lisp/pgg-pgp
/usr/local/share/emacs/site-lisp/semi/pgg-parse hides /usr/local/share/emacs/24.0.50/lisp/pgg-parse
/usr/local/share/emacs/site-lisp/semi/pgg-gpg hides /usr/local/share/emacs/24.0.50/lisp/pgg-gpg
/usr/local/share/emacs/site-lisp/semi/pgg-def hides /usr/local/share/emacs/24.0.50/lisp/pgg-def
/usr/local/share/emacs/site-lisp/flim/md4 hides /usr/local/share/emacs/24.0.50/lisp/md4
/usr/local/share/emacs/site-lisp/flim/hex-util hides /usr/local/share/emacs/24.0.50/lisp/hex-util
/usr/local/share/emacs/site-lisp/bitmap/po hides /usr/local/share/emacs/24.0.50/lisp/textmodes/po
/usr/local/share/emacs/site-lisp/flim/sasl hides /usr/local/share/emacs/24.0.50/lisp/net/sasl
/usr/local/share/emacs/site-lisp/flim/sasl-ntlm hides /usr/local/share/emacs/24.0.50/lisp/net/sasl-ntlm
/usr/local/share/emacs/site-lisp/flim/sasl-digest hides /usr/local/share/emacs/24.0.50/lisp/net/sasl-digest
/usr/local/share/emacs/site-lisp/flim/sasl-cram hides /usr/local/share/emacs/24.0.50/lisp/net/sasl-cram
/usr/local/share/emacs/site-lisp/flim/ntlm hides /usr/local/share/emacs/24.0.50/lisp/net/ntlm
/usr/local/share/emacs/site-lisp/flim/hmac-md5 hides /usr/local/share/emacs/24.0.50/lisp/net/hmac-md5
/usr/local/share/emacs/site-lisp/flim/hmac-def hides /usr/local/share/emacs/24.0.50/lisp/net/hmac-def
/usr/local/share/emacs/site-lisp/wl/rfc2368 hides /usr/local/share/emacs/24.0.50/lisp/mail/rfc2368
/usr/local/share/emacs/site-lisp/wl/utf7 hides /usr/local/share/emacs/24.0.50/lisp/gnus/utf7
/usr/local/share/emacs/site-lisp/semi/smime hides /usr/local/share/emacs/24.0.50/lisp/gnus/smime

Features:
(shadow sort gnus-util mail-extr message sendmail regexp-opt rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mailabbrev mail-utils gmm-utils mailheader
emacsbug package mime-w3m warnings advice help-fns advice-preload
w3m-load semantic/db-mode semantic/db semantic/idle semantic/format
semantic/tag-ls semantic/ctxt semantic/util-modes semantic/util semantic
semantic/tag semantic/lex semantic/fw mode-local ede/linux ede/emacs
ede/cpp-root ede/speedbar ede/files ede ede/source eieio-base
eieio-speedbar speedbar sb-image ezimage dframe easymenu assoc
eieio-custom wid-edit eieio byte-opt bytecomp byte-compile cedet
generic-x time japan-util tooltip ediff-hook vc-hooks lisp-float-type
mwheel x-win x-dnd tool-bar dnd fontset image fringe lisp-mode register
page menu-bar rfn-eshadow timer select scroll-bar mldrag mouse jit-lock
font-lock syntax facemenu font-core frame cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew
greek romanian slovak czech european ethiopic indian cyrillic chinese
case-table epa-hook jka-cmpr-hook help simple abbrev loaddefs button
minibuffer faces cus-face files text-properties overlay md5 base64
format env code-pages mule custom widget hashtable-print-readable
backquote make-network-process dynamic-setting system-font-setting
font-render-setting x-toolkit x multi-tty emacs)

[src-lread-old-backquote.diff (text/plain, attachment)]

Message #8 received at 6490 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Tetsurou Okazaki <okazaki <at> be.to>
Cc: 6490 <at> debbugs.gnu.org
Subject: Re: bug#6490: 24.0.50; src/lread.c: old style backquote bug?
Date: Wed, 23 Jun 2010 00:23:15 +0200

> Attached patch for Emacs fixes this error.

I'm glad the patch fixes things for you, since this patch indeed looks
perfectly harmless, but I'm a bit puzzled because it doesn't just look
harmless: it looks to me like the patch does change anything to the way
the code works.  So could you explain to me how&why the patch fixes
the problem?  I'm probably just overlooking some "obvious" detail,


        Stefan


> === modified file 'src/lread.c'
> --- src/lread.c	2010-06-16 14:10:02 +0000
> +++ src/lread.c	2010-06-22 07:48:58 +0000
> @@ -2693,21 +2693,26 @@
>  	 old-style.  For Emacs-25, we should completely remove this
>  	 first_in_list exception (old-style can still be obtained via
>  	 "(\`" anyway).  */
> -      if (first_in_list && (c = READCHAR, UNREAD (c), c == ' '))
> -	{
> -	  Vold_style_backquotes = Qt;
> -	  goto default_label;
> -	}
> -      else
> -	{
> -	  Lisp_Object value;
> -
> -	  new_backquote_flag++;
> -	  value = read0 (readcharfun);
> -	  new_backquote_flag--;
> -
> -	  return Fcons (Qbackquote, Fcons (value, Qnil));
> -	}
> +      {
> +        int next_char = READCHAR;
> +        UNREAD (next_char);
> +
> +	if (first_in_list && next_char == ' ')
> +	  {
> +	    Vold_style_backquotes = Qt;
> +	    goto default_label;
> +	  }
> +	else
> +	  {
> +	    Lisp_Object value;
> +
> +	    new_backquote_flag++;
> +	    value = read0 (readcharfun);
> +	    new_backquote_flag--;
> +
> +	    return Fcons (Qbackquote, Fcons (value, Qnil));
> +	  }
> +      }
 
>      case ',':
>        if (new_backquote_flag)

Message #11 received at 6490 <at> debbugs.gnu.org (full text, mbox):

From: Makoto Fujiwara <makoto <at> ki.nu>
To: 6490 <at> debbugs.gnu.org
Cc: Tetsurou Okazaki <okazaki <at> be.to>, Stefan Monnier <monnier <at> iro.umontreal.ca>
Subject: Re: bug#6490: 24.0.50; src/lread.c: old style backquote bug?
Date: Thu, 01 Jul 2010 13:14:48 +0900

first of all, I got the very much similar problem with
hnf-mode (2.5)
  http://nijino.homelinux.net/hnf-mode/

And the patch by Okazaki San fixed my problem. Thank you.

  I have looked at the patch, and minimized the changes in
diff wise.  It is logically exactly the same as the first
patch.

  This second patch also fixes my problem. If you look at this
patch, the changes almost nothing to the human being (just not
modifying char c).

diff --git a/src/lread.c b/src/lread.c
index c73f7f3..de01387 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -2693,7 +2693,11 @@ read1 (readcharfun, pch, first_in_list)
 	 old-style.  For Emacs-25, we should completely remove this
 	 first_in_list exception (old-style can still be obtained via
 	 "(\`" anyway).  */
-      if (first_in_list && (c = READCHAR, UNREAD (c), c == ' '))
+      {
+	 int next_char = READCHAR;
+	 UNREAD (next_char);
+
+      if (first_in_list && next_char == ' ')
 	{
 	  Vold_style_backquotes = Qt;
 	  goto default_label;
@@ -2708,6 +2712,7 @@ read1 (readcharfun, pch, first_in_list)
 
 	  return Fcons (Qbackquote, Fcons (value, Qnil));
 	}
+      }
 
     case ',':
       if (new_backquote_flag)

---
Makoto Fujiwara, 
Chiba, Japan, Narita Airport and Disneyland prefecture.

Message #14 received at 6490 <at> debbugs.gnu.org (full text, mbox):

From: Tetsurou Okazaki <okazaki <at> be.to>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Tetsurou Okazaki <okazaki <at> be.to>, 6490 <at> debbugs.gnu.org
Subject: Re: bug#6490: 24.0.50; src/lread.c: old style backquote bug?
Date: Thu, 01 Jul 2010 14:41:49 +0900

[Message part 1 (text/plain, inline)]

At Wed, 23 Jun 2010 00:23:15 +0200,
Stefan Monnier wrote:
> 
> > Attached patch for Emacs fixes this error.
> 
> I'm glad the patch fixes things for you, since this patch indeed looks
> perfectly harmless, but I'm a bit puzzled because it doesn't just look
> harmless: it looks to me like the patch does change anything to the way
> the code works.  So could you explain to me how&why the patch fixes
> the problem?  I'm probably just overlooking some "obvious" detail,

The changes committed in rev:100605 reassigns the next character to the variable `c'.
When the next character is SPC (32, #o40, #x20), old style backquote is detected.

  if (first_in_list && (c = READCHAR, UNREAD (c), c == ' '))
    {
      Vold_style_backquotes = Qt;
      goto default_label;
    }

But backquote handling is skipped because `c' is SPC.

    default_label:
      if (c <= 040) goto retry;

      ... old style backquote handling ...

My patch avoids reassignment of `c' not to skip old style backquote handling.

To keep more compatibility with released Emacs, it is preferable to
allow a character such as \r or \n after the old style backquote.

[src-lread-old-backquote2.diff (text/plain, attachment)]

Message #17 received at 6490 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
To: Tetsurou Okazaki <okazaki <at> be.to>
Cc: 6490 <at> debbugs.gnu.org
Subject: Re: bug#6490: 24.0.50; src/lread.c: old style backquote bug?
Date: Sun, 04 Jul 2010 23:50:26 +0200

>> > Attached patch for Emacs fixes this error.
>> I'm glad the patch fixes things for you, since this patch indeed looks
>> perfectly harmless, but I'm a bit puzzled because it doesn't just look
>> harmless: it looks to me like the patch does change anything to the way
>> the code works.  So could you explain to me how&why the patch fixes
>> the problem?  I'm probably just overlooking some "obvious" detail,

> The changes committed in rev:100605 reassigns the next character to
> the variable `c'.  When the next character is SPC (32, #o40, #x20),
> old style backquote is detected.

>   if (first_in_list && (c = READCHAR, UNREAD (c), c == ' '))
>     {
>       Vold_style_backquotes = Qt;
>       goto default_label;
>     }

> But backquote handling is skipped because `c' is SPC.

>     default_label:
>       if (c <= 040) goto retry;

>       ... old style backquote handling ...

> My patch avoids reassignment of `c' not to skip old style
> backquote handling.

Thanks, that makes perfect sense now.  I've installed it now.

> To keep more compatibility with released Emacs, it is preferable to
> allow a character such as \r or \n after the old style backquote.

I haven't seen any such situation yet, and since old-style backquotes are
on the way out (effectively obsolete since something like Emacs-20, and
officially obsolete since Emacs-22.1), I'll wait to see actual cases
before adding such exceptions,


        Stefan

Message #20 received at 6490 <at> debbugs.gnu.org (full text, mbox):

From: Makoto Fujiwara <makoto <at> ki.nu>
To: 6490 <at> debbugs.gnu.org
Cc: Tetsurou Okazaki <okazaki <at> be.to>, Stefan Monnier <monnier <at> IRO.UMontreal.CA>
Subject: Re: bug#6490: 24.0.50; src/lread.c: old style backquote bug?
Date: Mon, 05 Jul 2010 08:58:47 +0900

| To: Tetsurou Okazaki <okazaki <at> be.to>
| From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
| Subject: bug#6490: 24.0.50; src/lread.c: old style backquote bug?
| Date: Sun, 04 Jul 2010 23:50:26 +0200

	> To keep more compatibility with released Emacs, it is preferable to
	> allow a character such as \r or \n after the old style backquote.

Stefan> I haven't seen any such situation yet, and since old-style backquotes are
Stefan> on the way out (effectively obsolete since something like Emacs-20, and
Stefan> officially obsolete since Emacs-22.1), I'll wait to see actual cases
Stefan> before adding such exceptions,

You may found the typical example in flim-1.14.9/md4.el

     90 (defmacro md4-make-step (name func)
     91   (`
     92    (defun (, name) (a b c d xk s ac)
     93      (let*
     94          ((h1 (+ (car a) ((, func) (car b) (car c) (car d)) (car xk) (car ac)))
     95           (l1 (+ (cdr a) ((, func) (cdr b) (cdr c) (cdr d)) (cdr xk) (cdr ac)))
     96           (h2 (logand 65535 (+ h1 (lsh l1 -16))))
     97           (l2 (logand 65535 l1))
     98           ;; cyclic shift of 32 bits integer
     99           (h3 (logand 65535 (if (> s 15)
    100                                 (+ (lsh h2 (- s 32)) (lsh l2 (- s 16)))
    101                               (+ (lsh h2 s) (lsh l2 (- s 16))))))
    102           (l3 (logand 65535 (if (> s 15)
    103                                 (+ (lsh l2 (- s 32)) (lsh h2 (- s 16)))
    104                               (+ (lsh l2 s) (lsh h2 (- s 16)))))))
    105        (cons h3 l3)))))
    106
    107 (md4-make-step md4-round1 md4-F)

This is NOT compiled by the first patch. The second patch makes it, 
Thanks,
---
Makoto Fujiwara, 
Chiba, Japan, Narita Airport and Disneyland prefecture.

Message #23 received at 6490 <at> debbugs.gnu.org (full text, mbox):

From: Makoto Fujiwara <makoto <at> ki.nu>
To: 6490 <at> debbugs.gnu.org
Cc: Tetsurou Okazaki <okazaki <at> be.to>, Stefan Monnier <monnier <at> iro.umontreal.ca>
Subject: Re: bug#6490: 24.0.50; src/lread.c: old style backquote bug?
Date: Mon, 05 Jul 2010 10:51:21 +0900

Just for an information:

bbdb
  http://sourceforge.net/projects/bbdb
has the following lines in bbdb-2.34/lisp/bbdb-mhe.el:
     -----
     38 (defmacro bbdb/mh-cache-key (message)
     39   "Return a (numeric) key for MESSAGE"
     40   (`(let* ((attrs (file-attributes (, message)))
     41            (status-time (nth 6 attrs))
     42            (status-time-2 (cdr status-time))
     43            (inode (nth 10 attrs)))
     -----
I have added '(' at the end of the line, and then make it.

diff --git a/src/lread.c b/src/lread.c
index 16efd71..656d367 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -2693,21 +2693,26 @@ read1 (readcharfun, pch, first_in_list)
...

+       if (first_in_list && (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r' || ch == '\f' || ch == '('))

---
Makoto Fujiwara, 
Chiba, Japan, Narita Airport and Disneyland prefecture.

Message #32 received at 6490 <at> debbugs.gnu.org (full text, mbox):

From: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
To: Makoto Fujiwara <makoto <at> ki.nu>
Cc: Tetsurou Okazaki <okazaki <at> be.to>, Stefan Monnier <monnier <at> IRO.UMontreal.CA>,
	6490 <at> debbugs.gnu.org
Subject: Re: bug#6490: 24.0.50; src/lread.c: old style backquote bug?
Date: Wed, 21 Sep 2011 22:54:44 +0200

Makoto Fujiwara <makoto <at> ki.nu> writes:

> Stefan> officially obsolete since Emacs-22.1), I'll wait to see actual cases
> Stefan> before adding such exceptions,
>
> You may found the typical example in flim-1.14.9/md4.el
>
>      90 (defmacro md4-make-step (name func)
>      91   (`

Was there a decision made to just not support old-style "(`\n"
backquotes?  Reading the code, it looks like the "(` " style was added
back, but not the more extensive

ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r' || ch == '\f' || ch == '('

list suggested.  If the decision was to not support this, since all
support for old-style backquotes are scheduled to be removed in Emacs
25, this bug report can be closed.

-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/

Message #37 received at 6490-done <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
Cc: Tetsurou Okazaki <okazaki <at> be.to>, 6490-done <at> debbugs.gnu.org,
	Makoto Fujiwara <makoto <at> ki.nu>
Subject: Re: bug#6490: 24.0.50; src/lread.c: old style backquote bug?
Date: Wed, 21 Sep 2011 21:43:05 -0400

> list suggested.  If the decision was to not support this, since all
> support for old-style backquotes are scheduled to be removed in Emacs
> 25, this bug report can be closed.

Yes, it can be closed.


        Stefan

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