backward-sexp and insert-parentheses are lacking for Common Lisp

backward-sexp and insert-parentheses are lacking for Common Lisp

[Hannu Koivisto]

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In GNU Emacs 21.2.2 (i686-pc-linux-gnu, X toolkit)
 of 2002-03-26 on lynx
configured using `configure  --prefix=/usr/local/emacs-21 --with-xpm --with-jpeg --with-tiff --with-gif'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: fi_FI@euro
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: nil
  locale-coding-system: iso-latin-9
  default-enable-multibyte-characters: t

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

Assuming that point is right after the closing paren of #(1 2), for
example, backward-sexp moves the point right before the #
character.  It does not, however, move the point before the first
character of the following example Common Lisp forms in a buffer in
lisp-mode: #c(1 2) #2(1 2) #1a(1 2).  It should do that, in my
opinion.  Full description of the syntax pertaining to those
examples can be found at
<http://www.lispworks.com/reference/HyperSpec/Body/02_dh.htm>.

Also, when parens-require-spaces is non-nil, insert-parentheses
should not insert space after #c, #2 and #1a in the given examples.

Considering that lisp-mode may be used to edit something else than
Common Lisp, it would be sufficient at least for me if the proper
behaviour could be achieved with a configuration toggle of some
sort.  Or maybe it would be best to introduce common-lisp-mode?
This way people wouldn't need to always set lisp-indent-function to
common-lisp-indent-function and they could do CL-specific
customizations in that mode's hook, for example.

-- 
Hannu

Re: backward-sexp and insert-parentheses are lacking for Common Lisp

[Richard Stallman]

Implementing support for #-constructs that involve
a letter or digit, such as #c or #2, is not easy.
It would have to be done in syntax.c.

If you're interested in working on it, it is ok to try.

On the Lisp Machine I implemented a form of Lisp parsing
that always worked by parsing forward, even when the job
was moving backward.  Using text properties, that might
be feasible now in Emacs.  It would make this sort of thing
much easier.  But it is a substantial job.