C-j in Lisp interaction mode.

C-j in Lisp interaction mode.

[Luc Teirlinck]

C-j in Lisp interaction mode overrides `print-length' and
`print-level' using `eval-expression-print-length' and
`eval-expression-print-level'.  The purpose of the latter two
variables would seem to avoid printing huge expressions in the echo
area.  But I do not see any reason to use them in
`eval-print-last-sexp', bound to C-j in Lisp interaction mode.  I
would propose to change `eval-print-last-sexp' to just use
`print-length' and `print-level'.  Also,
`eval-expression-print-length' and `eval-expression-print-level' do
not seem to be documented in the Elisp manual, which makes their use
very confusing to beginning Elisp users.

Sincerely,

Luc.

Re: C-j in Lisp interaction mode.

[Richard Stallman]

    C-j in Lisp interaction mode overrides `print-length' and
    `print-level' using `eval-expression-print-length' and
    `eval-expression-print-level'.  The purpose of the latter two
    variables would seem to avoid printing huge expressions in the echo
    area.  But I do not see any reason to use them in
    `eval-print-last-sexp', bound to C-j in Lisp interaction mode.

I think it is a nuisance if C-j spews out tremendous quantities
of data.  I don't think this should be changed.

      Also,
    `eval-expression-print-length' and `eval-expression-print-level' do
    not seem to be documented in the Elisp manual, which makes their use
    very confusing to beginning Elisp users.

That I agree should be changed somehow.

Re: C-j in Lisp interaction mode.

[Richard Stallman]

    C-j in Lisp interaction mode overrides `print-length' and
    `print-level' using `eval-expression-print-length' and
    `eval-expression-print-level'.  The purpose of the latter two
    variables would seem to avoid printing huge expressions in the echo
    area.  But I do not see any reason to use them in
    `eval-print-last-sexp', bound to C-j in Lisp interaction mode.

I think it is a nuisance if C-j spews out tremendous quantities
of data.  I don't think this should be changed.

      Also,
    `eval-expression-print-length' and `eval-expression-print-level' do
    not seem to be documented in the Elisp manual, which makes their use
    very confusing to beginning Elisp users.

They are documented in the Emacs manual, where the commands are
documented.  I'm not against putting them in the Lisp manual, but is
there a place where they would fit?  The evaluation commands are not
documented in that manual.

Re: C-j in Lisp interaction mode.

[Luc Teirlinck]

Richard Stallman wrote:
	 
	 Also,
       `eval-expression-print-length' and `eval-expression-print-level' do
       not seem to be documented in the Elisp manual, which makes their use
       very confusing to beginning Elisp users.

   They are documented in the Emacs manual, where the commands are
   documented.  I'm not against putting them in the Lisp manual, but is
   there a place where they would fit?  The evaluation commands are not
   documented in that manual.

The diff below would document `eval-expression-print-length' and
`eval-expression-print-level' straight after the definitions of
`print-length' and `print-level'.  It would prevent readers of the
Elisp manual who try out the latter two variables in the *scratch*
buffer from being completely confused by Emacs' apparent lack of
response in as far as C-j, C-x C-e or similar, is concerned.  There is
a reference to the section of the Emacs manual which you mentioned.
If the diff is OK, I could commit it to the CVS, if desired.

===File ~/streamsdiff=======================================
cd ~/
diff -c /home/teirllm/streams.old.texi /home/teirllm/streams.texi
*** /home/teirllm/streams.old.texi	Tue Jul 22 12:19:57 2003
--- /home/teirllm/streams.texi	Fri Aug  8 20:32:27 2003
***************
*** 771,776 ****
--- 771,784 ----
  @code{nil} (which is the default) means no limit.
  @end defvar
  
+ @defopt eval-expression-print-length
+ @defoptx eval-expression-print-level
+ These are the values for @code{print-length} and @code{print-level}
+ used by @code{eval-expression}, and thus, indirectly, by many
+ interactive evaluation commands (@pxref{Lisp Eval,, Evaluating
+ Emacs-Lisp Expressions, emacs, The GNU Emacs Manual}).
+ @end defopt
+ 
    These variables are used for detecting and reporting circular
  and shared structure---but they are only defined in Emacs 21.
  

Diff finished at Fri Aug  8 21:18:10
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