README: Add info about MELPA

Instead of an Elisp type error.

README.org

@@ -18,14 +18,9 @@ discuss anything.
 pipewire-0 currently requires presence of PipeWire command line tools,
 namely [[https://docs.pipewire.org/page_man_pw_cli_1.html][pw-cli]] and [[https://docs.pipewire.org/page_man_pw_metadata_1.html][pw-metadata]].
 
-To install pipewire-0, put the *.el files to a site-lisp directory and
+You can install pipewire-0 from [[https://melpa.org/#/pipewire][MELPA]].  If you use [[https://github.com/radian-software/straight.el][straight.el]] and
-add the following line to your Emacs configuration:
+prefer using source repos directly, you can install pipewire-0 as
-
+follows:
-   #+begin_src elisp
-(require ’pipewire)
-   #+end_src
-
-Or if you use [[https://github.com/radian-software/straight.el][straight.el]], you can install pipewire-0 as follows:
 
    #+begin_src elisp
 (straight-use-package
@@ -34,6 +29,13 @@ Or if you use [[https://github.com/radian-software/straight.el][straight.el]], y
               :local-repo "pipewire-0"))
    #+end_src
 
+To install pipewire-0 manually, put the *.el files to a site-lisp
+directory and add the following line to your Emacs configuration:
+
+   #+begin_src elisp
+(require ’pipewire)
+   #+end_src
+
 ** User interface
 
 =M-x pipewire= enters a buffer with PipeWire objects:

pipewire.el

@@ -25,11 +25,18 @@
 
 ;;; Commentary:
 ;;
-;; PipeWire user interface based on pipewire-lib.
+;; PipeWire user interface and library.
-;; An interactive buffer can be displayed using `M-x pipewire'.
+;; It currently uses pw-cli and pw-metadata command line utilities to
+;; interact with PipeWire.
+;;
+;; An interactive PipeWire buffer can be displayed using `M-x pipewire'.
+;; There you can view basic PipeWire status and change some settings.
 ;; `pipewire-increase-volume', `pipewire-decrease-volume' and
-;; `pipewire-toggle-muted' functions are also suitable to bind on the
+;; `pipewire-toggle-muted' functions can be used also standalone and
-;; multimedia keys.
+;; are suitable to bind on the multimedia keys.
+;;
+;; The package can be used also non-interactively in Elisp programs.
+;; See pipewire-lib.el source file for available functions.
 
 ;;; Code:
 
@@ -150,7 +157,7 @@ The indicator is displayed only on graphical terminals."
   (interactive)
   (when (and (not (eq major-mode 'pipewire-mode))
              (not (equal (buffer-name) pipewire-buffer)))
-    (error "Not in a PipeWire buffer"))
+    (user-error "Not in a PipeWire buffer"))
   (pipewire-lib-refresh)
   (let ((inhibit-read-only t)
         (default-ids (mapcar #'cdr (pipewire-lib-default-nodes)))
@@ -287,9 +294,10 @@ object.  Otherwise apply it on the default audio sink."
 (defun pipewire-toggle-microphone ()
   "Switch mute status of the default audio input."
   (interactive)
-  (let* ((object (car (pipewire-lib-default-capture-ports)))
+  (let ((object (car (pipewire-lib-default-capture-ports))))
-         (muted-p (pipewire-lib-toggle-mute object)))
+    (if object
-    (pipewire--update-muted object muted-p)))
+        (pipewire--update-muted object (pipewire-lib-toggle-mute object))
+      (user-error "No default audio input"))))
 
 ;;;###autoload
 (defun pipewire-set-volume (volume &optional object single-p)
@@ -384,7 +392,7 @@ Otherwise ask for the Node to set as the default Node."
         ;; Without this, ports of the device may not be displayed on the update:
         (sit-for 0)
         (pipewire--update))
-    (error "Nothing to set a profile for here")))
+    (user-error "Nothing to set a profile for here")))
 
 (defun pipewire-properties ()
   "Display properties of the object at the current point."
@@ -398,7 +406,7 @@ Otherwise ask for the Node to set as the default Node."
             (insert (format "%s: %s\n" p (pipewire-lib-object-value object p)))))
         (goto-char (point-min))
         (view-mode))
-    (error "No PipeWire object here")))
+    (user-error "No PipeWire object here")))
 
 (defvar pipewire-mode-map
   (let ((map (make-sparse-keymap)))