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.

2 files changed, 100 insertions, 0 deletions

diff --git a/test/lisp/progmodes/elisp-mode-tests.el b/test/lisp/progmodes/elisp-mode-tests.el
index 5edb590b1e5..03ae8481ee5 100644
--- a/test/lisp/progmodes/elisp-mode-tests.el
+++ b/test/lisp/progmodes/elisp-mode-tests.el
@@ -132,6 +132,54 @@
       (call-interactively #'eval-last-sexp)
       (should (equal (current-message) "t")))))
 
+(ert-deftest eval-last-sexp-print-format-small-int ()
+  (with-temp-buffer
+    (let ((current-prefix-arg '(4)))
+      (erase-buffer) (insert "?A")
+      (call-interactively #'eval-last-sexp)
+      (should (equal (buffer-string) "?A65")))
+    (let ((current-prefix-arg 0))
+      (erase-buffer) (insert "?A")
+      (call-interactively #'eval-last-sexp)
+      (should (equal (buffer-string) "?A65 (#o101, #x41, ?A)")))))
+
+(ert-deftest eval-last-sexp-print-format-small-int-echo ()
+  (skip-unless (not noninteractive))
+  (with-temp-buffer
+    (let ((current-prefix-arg nil))
+      (erase-buffer) (insert "?A") (message nil)
+      (call-interactively #'eval-last-sexp)
+      (should (equal (current-message) "65 (#o101, #x41, ?A)")))))
+
+(ert-deftest eval-last-sexp-print-format-large-int ()
+  (with-temp-buffer
+    (let ((eval-expression-print-maximum-character ?A))
+      (let ((current-prefix-arg '(4)))
+        (erase-buffer) (insert "?B")
+        (call-interactively #'eval-last-sexp)
+        (should (equal (buffer-string) "?B66")))
+      (let ((current-prefix-arg 0))
+        (erase-buffer) (insert "?B")
+        (call-interactively #'eval-last-sexp)
+        (should (equal (buffer-string) "?B66 (#o102, #x42)")))
+      (let ((current-prefix-arg -1))
+        (erase-buffer) (insert "?B")
+        (call-interactively #'eval-last-sexp)
+        (should (equal (buffer-string) "?B66 (#o102, #x42, ?B)"))))))
+
+(ert-deftest eval-last-sexp-print-format-large-int-echo ()
+  (skip-unless (not noninteractive))
+  (with-temp-buffer
+    (let ((eval-expression-print-maximum-character ?A))
+      (let ((current-prefix-arg nil))
+        (erase-buffer) (insert "?B") (message nil)
+        (call-interactively #'eval-last-sexp)
+        (should (equal (current-message) "66 (#o102, #x42)")))
+      (let ((current-prefix-arg '-))
+        (erase-buffer) (insert "?B") (message nil)
+        (call-interactively #'eval-last-sexp)
+        (should (equal (current-message) "66 (#o102, #x42, ?B)"))))))
+
 ;;; xref
 
 (defun xref-elisp-test-descr-to-target (xref)
diff --git a/test/lisp/simple-tests.el b/test/lisp/simple-tests.el
index b74e28ccaf1..180dcc0a209 100644
--- a/test/lisp/simple-tests.el
+++ b/test/lisp/simple-tests.el
@@ -396,5 +396,57 @@ See Bug#21722."
         (call-interactively #'eval-expression)
         (should (equal (current-message) "t"))))))
 
+(ert-deftest eval-expression-print-format-small-int ()
+  (with-temp-buffer
+    (cl-letf (((symbol-function 'read--expression) (lambda (&rest _) ?A)))
+      (let ((current-prefix-arg '(4)))
+        (erase-buffer)
+        (call-interactively #'eval-expression)
+        (should (equal (buffer-string) "65")))
+      (let ((current-prefix-arg 0))
+        (erase-buffer)
+        (call-interactively #'eval-expression)
+        (should (equal (buffer-string) "65 (#o101, #x41, ?A)"))))))
+
+(ert-deftest eval-expression-print-format-small-int-echo ()
+  (skip-unless (not noninteractive))
+  (with-temp-buffer
+    (cl-letf (((symbol-function 'read--expression) (lambda (&rest _) ?A)))
+      (let ((current-prefix-arg nil))
+        (message nil)
+        (call-interactively #'eval-expression)
+        (should (equal (current-message) "65 (#o101, #x41, ?A)"))))))
+
+(ert-deftest eval-expression-print-format-large-int ()
+  (with-temp-buffer
+    (cl-letf (((symbol-function 'read--expression) (lambda (&rest _) ?B))
+              (eval-expression-print-maximum-character ?A))
+      (let ((current-prefix-arg '(4)))
+        (erase-buffer)
+        (call-interactively #'eval-expression)
+        (should (equal (buffer-string) "66")))
+      (let ((current-prefix-arg 0))
+        (erase-buffer)
+        (call-interactively #'eval-expression)
+        (should (equal (buffer-string) "66 (#o102, #x42)")))
+      (let ((current-prefix-arg -1))
+        (erase-buffer)
+        (call-interactively #'eval-expression)
+        (should (equal (buffer-string) "66 (#o102, #x42, ?B)"))))))
+
+(ert-deftest eval-expression-print-format-large-int-echo ()
+  (skip-unless (not noninteractive))
+  (with-temp-buffer
+    (cl-letf (((symbol-function 'read--expression) (lambda (&rest _) ?B))
+              (eval-expression-print-maximum-character ?A))
+      (let ((current-prefix-arg nil))
+        (message nil)
+        (call-interactively #'eval-expression)
+        (should (equal (current-message) "66 (#o102, #x42)")))
+      (let ((current-prefix-arg '-))
+        (message nil)
+        (call-interactively #'eval-expression)
+        (should (equal (current-message) "66 (#o102, #x42, ?B)"))))))
+
 (provide 'simple-test)
 ;;; simple-test.el ends here