New option show-paren-context-when-offscreen

* lisp/simple.el (blink-paren-open-paren-line-string): Extract
functionality that shows the open paren line in the echo area into its
own function, to reuse it from paren.el.
(blink-matching-open): Use blink-paren-open-paren-line-string.
* lisp/paren.el (show-paren-context-when-offscreen): New option
show-paren-context-when-offscreen.
(show-paren-function): Implement it using
blink-paren-open-paren-line-string.
* lisp/emacs-lisp/eldoc.el (eldoc-display-message-no-interference-p):
Make sure the feature works well with eldoc.
* test/lisp/paren-tests.el (paren-tests-open-paren-line): Test
blink-paren-open-paren-line-string.
* doc/emacs/programs.texi (Matching): Update the documentation.
* etc/NEWS: And announce the new feature.

1 files changed, 8 insertions, 1 deletions

diff --git a/lisp/emacs-lisp/eldoc.el b/lisp/emacs-lisp/eldoc.el
index a1c3c3268f2..b30d3fc30f4 100644
--- a/lisp/emacs-lisp/eldoc.el
+++ b/lisp/emacs-lisp/eldoc.el
@@ -380,7 +380,14 @@ Also store it in `eldoc-last-message' and return that value."
 ;; it undesirable to print eldoc messages right this instant.
 (defun eldoc-display-message-no-interference-p ()
   "Return nil if displaying a message would cause interference."
-  (not (or executing-kbd-macro (bound-and-true-p edebug-active))))
+  (not (or executing-kbd-macro
+           (bound-and-true-p edebug-active)
+           ;; The following configuration shows "Matches..." in the
+           ;; echo area when point is after a closing bracket, which
+           ;; conflicts with eldoc.
+           (and show-paren-context-when-offscreen
+                (not (pos-visible-in-window-p
+                      (overlay-end show-paren--overlay)))))))
 
 
 (defvar eldoc-documentation-functions nil