char-uppercase-p: New predicate

Return non-nil if its argument is an uppercase character.

Suggested in Bug#54804.

* lisp/subr.el (char-uppercase-p): New defun.
* etc/NEWS (Lisp Changes in Emacs 29.1): Announce it
* doc/lispref/display.texi (Size of Displayed Text): Document it.
* test/lisp/subr-tests.el (test-char-uppercase-p): Add a test.

1 files changed, 7 insertions, 0 deletions

diff --git a/test/lisp/subr-tests.el b/test/lisp/subr-tests.el
index 89803e5ce2e..a25eb363b01 100644
--- a/test/lisp/subr-tests.el
+++ b/test/lisp/subr-tests.el
@@ -1074,5 +1074,12 @@ final or penultimate step during initialization."))
       (should (= subr-test--local 2))
       (should-not (boundp 'subr-test--unexist)))))
 
+(ert-deftest test-char-uppercase-p ()
+  "Tests for `char-uppercase-p'."
+  (dolist (c (list ?R ?S ?Ω ?Ψ))
+    (should (char-uppercase-p c)))
+  (dolist (c (list ?a ?b ?α ?β))
+    (should-not (char-uppercase-p c))))
+
 (provide 'subr-tests)
 ;;; subr-tests.el ends here