feat(functions): Add predicate function to determine last window

Adds a function that can be used to check whether the current buffer
is displayed in the "last" window of the active frame.

The intention is to use this predicate to modify the modeline display
to only show miscellaneous information (time, battery percentage etc.)
on the last window instead of duplicating it.

1 files changed, 10 insertions, 0 deletions

diff --git a/init/functions.el b/init/functions.el
index ebcc5b5f7d..4ca7cedb27 100644
--- a/init/functions.el
+++ b/init/functions.el
@@ -204,4 +204,14 @@ Including indent-buffer, which should not be called automatically on save."
   (epg-sign-string (epg-make-context) "dummy")
   nil)
 
+(defun bottom-right-window-p ()
+  "Determines whether the last (i.e. bottom-right) window of the
+  active frame is showing the buffer in which this function is
+  executed."
+  (let* ((frame (selected-frame))
+         (right-windows (window-at-side-list frame 'right))
+         (bottom-windows (window-at-side-list frame 'bottom))
+         (last-window (car (seq-intersection right-windows bottom-windows))))
+    (eq (current-buffer) (window-buffer last-window))))
+
 (provide 'functions)