Don’t err in pip-frame-remove-buffer if there is no PIP frame

This is useful e.g. to prevent the error when a PIP frame with a
temporarily displayed buffer is deleted before the buffer timer
attempts to remove the buffer.

README.org

@@ -43,6 +43,26 @@ this utility:
 
 * How?
 
+** Installation
+
+You can install pip-frame.el from [[https://melpa.org/#/pip-frame][MELPA]].  If you use [[https://github.com/radian-software/straight.el][straight.el]] and
+prefer using source repos directly, you can install pip-frame.el as
+follows:
+
+   #+begin_src elisp
+(straight-use-package
+ '(pip-frame :type git
+             :repo "https://git.zamazal.org/pdm/pip-frame"
+             :local-repo "pip-frame"))
+   #+end_src
+
+For manual installation, simply put [[./pip-frame.el][pip-frame.el]] file to your
+=site-lisp= directory and add the following to your Emacs configuration:
+
+   #+begin_src elisp
+(require ’pip-frame)
+   #+end_src
+
 ** Commands
 
 The PIP frame is created using =M-x pip-frame-add-buffer= command.  You

pip-frame.el

@@ -1,7 +1,13 @@
-;;; pip-frame.el --- PIP frame support  -*- lexical-binding: t -*-
+;;; pip-frame.el --- Display and manage a PIP frame  -*- lexical-binding: t -*-
 
 ;; Copyright (C) 2022 Milan Zamazal <pdm@zamazal.org>
 
+;; Author: Milan Zamazal <pdm@zamazal.org>
+;; Version: 1
+;; Package-Requires: ((emacs "25.1"))
+;; Keywords: frames
+;; URL: https://git.zamazal.org/pdm/pip-frame
+
 ;; COPYRIGHT NOTICE
 ;;
 ;; This program is free software: you can redistribute it and/or modify
@@ -17,6 +23,8 @@
 ;; You should have received a copy of the GNU General Public License
 ;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+;;; Commentary:
+;;
 ;; Display a floating Emacs frame with selected buffers.
 ;; Similar to PIP on screens.  Probably most useful in EXWM.
 ;;
@@ -25,10 +33,13 @@
 ;; `M-x pip-frame-remove-buffer' or close the whole frame with
 ;; `M-x pip-frame-delete-frame'.
 
+;;; Code:
+
 (require 'cl-lib)
 
 (defgroup pip-frame ()
-  "Display PIP frame.")
+  "Display PIP frame."
+  :group 'frames)
 
 (defcustom pip-frame-scale 4
   "How many times to shrink the PIP frame relative to the display size."
@@ -50,6 +61,7 @@ Usually, the value should be larger than 0 and much smaller than 1."
 (defcustom pip-frame-parameters
   '((left . 0.9)
     (top .  0.9)
+    (tab-bar-lines . 0)
     (minibuffer . nil))
   "Alist of frame parameters to use for the PIP frame.
 The frame size is determined automatically using `pip-frame-scale'
@@ -71,7 +83,7 @@ custom option but it can be overriden here."
 
 (defun pip-frame--get-frame (&optional no-error)
   (let ((frame (cl-find pip-frame--name (frame-list)
-                        :key #'(lambda (f) (frame-parameter f 'name)))))
+                        :key (lambda (f) (frame-parameter f 'name)))))
     (or frame
         (unless no-error
           (error "No PIP frame")))))
@@ -85,8 +97,8 @@ custom option but it can be overriden here."
         (frame-inhibit-implied-resize t)
         (face-height (round (/ (face-attribute 'default :height) pip-frame-font-scale))))
     (set-face-attribute 'default frame :height face-height)
-    (mapc #'(lambda (p) (set-face-attribute 'default frame (car p) (cdr p)))
-          pip-frame-face-attributes)
+    (dolist (p pip-frame-face-attributes)
+      (set-face-attribute 'default frame (car p) (cdr p)))
     (set-window-buffer (car (window-list frame)) buffer)
     frame))
 
@@ -102,11 +114,11 @@ custom option but it can be overriden here."
   (let ((windows (window-list (pip-frame--get-frame))))
     (unless (and temporary
                  (cl-find buffer windows :key #'window-buffer :test #'eq))
-      (let* ((sizes (mapcar #'(lambda (w)
-                                (let ((width (window-body-width w t))
-                                      (height (window-body-height w t)))
-                                  (cons (+ (* width width) (* height height))
-                                        w)))
+      (let* ((sizes (mapcar (lambda (w)
+                              (let ((width (window-body-width w t))
+                                    (height (window-body-height w t)))
+                                (cons (+ (* width width) (* height height))
+                                      w)))
                             windows))
              (largest (cdr (cl-first (cl-sort sizes #'> :key #'car))))
              (side (if (> (window-body-width largest t)
@@ -163,14 +175,15 @@ If the buffer is not present in the PIP frame, do nothing."
   (interactive (list (completing-read "Remove PIP buffer: "
                                       (mapcar #'buffer-name (pip-frame--buffers))
                                       nil t)))
-  (let* ((windows (window-list (pip-frame--get-frame)))
-         (buffer (get-buffer buffer-or-name))
-         (windows-to-delete (cl-remove buffer windows
-                                       :key #'window-buffer
-                                       :test-not #'eq)))
-    (if (= (length windows-to-delete) (length windows))
-        (pip-frame-delete-frame)
-      (mapc #'delete-window windows-to-delete))))
+  (if-let ((frame (pip-frame--get-frame t))
+           (windows (window-list frame))
+           (buffer (get-buffer buffer-or-name))
+           (windows-to-delete (cl-remove buffer windows
+                                         :key #'window-buffer
+                                         :test-not #'eq)))
+      (if (= (length windows-to-delete) (length windows))
+          (pip-frame-delete-frame)
+        (seq-do #'delete-window windows-to-delete))))
 
 (defun pip-frame--move (x y)
   (let ((frame (pip-frame--get-frame)))
@@ -184,18 +197,22 @@ If the buffer is not present in the PIP frame, do nothing."
       (round (* pip-frame-move-step (nth (if vertical 3 2) workarea))))))
 
 (defun pip-frame-move-left ()
+  "Move the PIP frame left."
   (interactive)
   (pip-frame--move (- (pip-frame--move-step nil)) 0))
 
 (defun pip-frame-move-right ()
+  "Move the PIP frame right."
   (interactive)
   (pip-frame--move (pip-frame--move-step nil) 0))
 
 (defun pip-frame-move-up ()
+  "Move the PIP frame up."
   (interactive)
   (pip-frame--move 0 (- (pip-frame--move-step t))))
 
 (defun pip-frame-move-down ()
+  "Move the PIP frame down."
   (interactive)
   (pip-frame--move 0 (pip-frame--move-step t)))
 
@@ -216,3 +233,9 @@ Any other key stops this command and executes its own command."
   (set-transient-map pip-frame-move-map t))
 
 (provide 'pip-frame)
+
+;; Local Variables:
+;; checkdoc-force-docstrings-flag: nil
+;; End:
+
+;;; pip-frame.el ends here