Re: printing most-negative-fixnum fails

[Juri Linkov <juri@jurta.org>]

Kenichi Handa <handa@m17n.org> writes:
> And make C-u C-u C-x C-e show a real character.  It's very
> unfortunate that we can't use C-u C-x C-e for that (I've
> never used it).

It's a good idea.  But it seems inconsistent since C-u inserts
a result into the current buffer, but C-u C-u will not.  And it
requires changes in the semantics of prefix arguments in existing
functions which is not too good.

But another similar idea is to show a character on successive C-x C-e
calls, i.e. to use the condition (eq last-command 'eval-last-sexp)
to decide whether to show a character.  So C-x C-e C-x C-e will show
a character in addition to numeric values.  In this case the function
`eval-expression-print-format' will be:

(defun eval-expression-print-format (value)
  "Format VALUE as a result of evaluated expression.
Return a formatted string which is displayed in the echo area
in addition to the value printed by prin1 in functions that
display results of expression evaluation."
  (if (integerp value)
      (let ((char-string
             (if (or (and (boundp 'edebug-active) edebug-active)
                     (and (eq this-command 'eval-last-sexp)
                          (eq this-command last-command)))
                 (prin1-char value))))
        (if char-string
            (format " (0%o, 0x%x) = %s" value value char-string)
          (format " (0%o, 0x%x)" value value)))))

and it will be called from four functions: `edebug-compute-previous-result',
`edebug-eval-expression', `eval-expression' and `eval-last-sexp-print-value'.

-- 
Juri Linkov
http://www.jurta.org/emacs/