Limit integers printed as characters (Bug#16828)

* lisp/simple.el (eval-expression-print-maximum-character): New
variable.
(eval-expression-print-format): Only display value as character if
it's less than or equal to `eval-expression-print-maximum-character'.
(eval-expression-get-print-arguments): Check
eval-expression-print-maximum-character, allow negative arg to
override it.
(eval-expression):
* lisp/progmodes/elisp-mode.el (elisp--eval-last-sexp):
(elisp--eval-last-sexp-print-value): Handle new variable.
* doc/emacs/building.texi (Lisp Eval): Document new variable and
behavior.
* etc/NEWS: Announce it.
* test/lisp/progmodes/elisp-mode-tests.el
(eval-last-sexp-print-format-small-int)
(eval-last-sexp-print-format-small-int-echo)
(eval-last-sexp-print-format-large-int)
(eval-last-sexp-print-format-large-int-echo):
* test/lisp/simple-tests.el (eval-expression-print-format-small-int)
(eval-expression-print-format-small-int-echo)
(eval-expression-print-format-large-int)
(eval-expression-print-format-large-int-echo): New tests.

1 files changed, 4 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 340718ecbc4..aa579b11c7a 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -352,6 +352,10 @@ environment variable on a remote machine to emacsclient, and
 use the local Emacs to edit remote files via Tramp.  See the node
 "emacsclient Options" in the user manual for the details.
 
++++
+** The new variable 'eval-expression-print-maximum-character' prevents
+large integers from being displayed as characters.
+
 
 * Editing Changes in Emacs 26.1