transpose-sexps doesn't transpose character literals and symbols properly in lisp-mode

transpose-sexps doesn't transpose character literals and symbols properly in lisp-mode

[Matthew X. Economou]

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In GNU Emacs 21.1.1 (i386-msvc-nt5.1.2600)
 of 2001-10-22 on buffy
configured using `configure --with-msvc (12.00)'
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: nil
  value of $LANG: ENU
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

In lisp-mode, with point between the "0" and "c" characters in the
following portion of code, the function transpose-sexps will only
transpose the "0" and "c" characters, not the "#\0" and "c"
expressions:

    (char= #\0 c)
              ^the cursor is here before pressing M-C-t

    (char= #\c 0)
              ^the entire expression #\0 should have been swapped

Elements of the form "#\<<symbol>>" are character literals in Common
Lisp.  Note that movement commands forward-sexp and backward-sexp work
properly (that is, if point is before the text "#\0", pressing M-C-f
will position the point at the character immediately after the "0").

Recent input:
p a r t SPC n C-x C-s C-p C-p C-p C-p C-p <return> 
M-( M-( a n d M-( n u l l SPC p a r t M-) M-( c h a 
r = SPC c SPC # \ 0 C-M-b C-M-b C-M-t C-_ C-M-k C-M-b 
C-y SPC C-f C-d C-x C-s C-h v C-g C-h v e m a c s - 
v e r s <tab> <return> C-x 4 b <return> <menu-bar> 
<help-menu> <emacs-problems> C-s l i s p <return> C-s 
C o m m o n SPC L M-< C-x k <return> <menu-bar> <help-menu> 
<report-emacs-bug>

Recent messages:
Undo!
Mark set
Wrote u:/src/address.lisp
setq: Quit
Loading pp...done
Type C-x 4 b RET to restore the other window.  C-M-v to scroll the help.
Type C-h for help, h for commands, q to quit.
Mark saved where search started [2 times]
Mark set
Loading emacsbug...done

-- 
Matthew X. Economou <xenophon@irtnog.org> - Unsafe at any clock speed!
I'm proud of my Northern Tibetian heritage! (http://www.subgenius.com)
Max told his friend that he'd just as soon not go hiking in the hills.
Said he, "I'm an anti-climb Max."  [So is that punchline.]

Re: transpose-sexps doesn't transpose character literals and symbols properly in lisp-mode

[Richard Stallman]

	(char= #\0 c)
		  ^the cursor is here before pressing M-C-t

	(char= #\c 0)
		  ^the entire expression #\0 should have been swapped

The problem is actually in forward-sexp, as we can demonstrate
by typing C-M-b instead of C-M-t.  Unfortunately that makes
it rather hard to fix.  However, I am a little surprised that
it doesn't understand backslash--it used to.

Stefan, might you be interested in looking at this?

Re: transpose-sexps doesn't transpose character literals and symbols properly in lisp-mode

[Stefan Monnier]

> 	(char= #\0 c)
> 		  ^the cursor is here before pressing M-C-t
> 
> 	(char= #\c 0)
> 		  ^the entire expression #\0 should have been swapped
> 
> The problem is actually in forward-sexp, as we can demonstrate
> by typing C-M-b instead of C-M-t.  Unfortunately that makes
> it rather hard to fix.  However, I am a little surprised that
> it doesn't understand backslash--it used to.
> 
> Stefan, might you be interested in looking at this?

M-C-b worked correctly on #\dd but not on #\d (i.e. the treatment of
last-char-is-quoted was wrong).  It should be fixed now,


	Stefan

Re: transpose-sexps doesn't transpose character literals and symbols properly in lisp-mode

[Richard Stallman]

Thanks for fixing that.