Support prelude/start-process

If you refer to the previous commit where I change shell-command usages to
start-process function calls, you'll see the rationale for why I prefer
start-process.

This commit introduces a more ergonomic API for start-process that fits most of
my current use-cases of it. This cleans up the code. I have introduced a bug in
the way that I'm tokenizing the COMMAND value. I've tracked that with a
TODO. For now it only affects the `xmodmap -e '<command-string>'` calls, which
isn't too disruptive.

8 files changed, 93 insertions, 62 deletions

diff --git a/configs/shared/.emacs.d/wpc/display.el b/configs/shared/.emacs.d/wpc/display.el
index 716f3e5f5742..7f2f5e034609 100644
--- a/configs/shared/.emacs.d/wpc/display.el
+++ b/configs/shared/.emacs.d/wpc/display.el
@@ -14,6 +14,12 @@
 ;;; Code:
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Dependencies
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(require 'prelude)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Constants
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
@@ -31,17 +37,18 @@
 (defun display/enable-4k ()
   "Attempt to connect to my 4K monitor."
   (interactive)
-  (shell-command
-   (string/format "xrandr --output %s --dpi 144 --auto --right-of %s"
-                  display/4k
-                  display/primary)))
+  (prelude/start-process
+   :name "display"
+   :command (string/format "xrandr --output %s --dpi 144 --auto --right-of %s"
+                           display/4k
+                           display/primary)))
 
 (defun display/disable-4k ()
   "Disconnect from the 4K monitor."
   (interactive)
-  (shell-command
-   (string/format "xrandr --output %s --off"
-                  display/4k)))
+  (prelude/start-process
+   :name "display/disable-4k"
+   :command (string/format "xrandr --output %s --off" display/4k)))
 
 (provide 'display)
 ;;; display.el ends here
diff --git a/configs/shared/.emacs.d/wpc/keyboard.el b/configs/shared/.emacs.d/wpc/keyboard.el
index ac778d1698d8..176ac074dcd0 100644
--- a/configs/shared/.emacs.d/wpc/keyboard.el
+++ b/configs/shared/.emacs.d/wpc/keyboard.el
@@ -51,8 +51,9 @@
                                    (rate keyboard/repeat-rate)
                                    (delay keyboard/repeat-delay))
   "Use xset to set the key-repeat RATE and DELAY."
-   (shell-command
-    (string/format "xset r rate %s %s" delay rate)))
+  (prelude/start-process
+   :name "keyboard/set-key-repeat"
+   :command (string/format "xset r rate %s %s" delay rate)))
 
 ;; NOTE: Settings like this are machine-dependent. For instance I only need to
 ;; do this on my laptop and other devices where I don't have access to my split
@@ -64,8 +65,12 @@
 (defun keyboard/swap-caps-lock-and-escape ()
   "Swaps the caps lock and escape keys using xmodmap."
   (interactive)
-  (shell-command "xmodmap -e 'remove Lock = Caps_Lock'")
-  (shell-command "xmodmap -e 'keysym Caps_Lock = Escape'"))
+  (prelude/start-process
+   :name "keyboard/swap-caps-lock-and-escape"
+   :command "xmodmap -e 'remove Lock = Caps_Lock'")
+  (prelude/start-process
+   :name "keyboard/swap-caps-lock-and-escape"
+   :command "xmodmap -e 'keysym Caps_Lock = Escape'"))
 
 (defun keyboard/inc-repeat-rate ()
   "Increment `keyboard/repeat-rate'."
diff --git a/configs/shared/.emacs.d/wpc/playback.el b/configs/shared/.emacs.d/wpc/playback.el
index 9ab1e30ef0ac..e7ad4b2481a4 100644
--- a/configs/shared/.emacs.d/wpc/playback.el
+++ b/configs/shared/.emacs.d/wpc/playback.el
@@ -6,20 +6,36 @@
 
 ;;; Code:
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Dependencies
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(require 'prelude)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Library
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
 (defun playback/prev ()
   "Move to the previous song."
   (interactive)
-  (shell-command "playerctl previous"))
+  (prelude/start-process
+   :name "playback/prev"
+   :command "playerctl previous"))
 
 (defun playback/next ()
   "Move to the next song."
   (interactive)
-  (shell-command "playerctl next"))
+  (prelude/start-process
+   :name "playback/next"
+   :command "playerctl next"))
 
 (defun playback/play-pause ()
   "Play or pause the current song."
   (interactive)
-  (shell-command "playerctl play-pause"))
+  (prelude/start-process
+   :name "playback/play-pause"
+   :command "playerctl play-pause"))
 
 (provide 'playback)
 ;;; playback.el ends here
diff --git a/configs/shared/.emacs.d/wpc/prelude.el b/configs/shared/.emacs.d/wpc/prelude.el
index fb459627899d..c1579d558985 100644
--- a/configs/shared/.emacs.d/wpc/prelude.el
+++ b/configs/shared/.emacs.d/wpc/prelude.el
@@ -20,7 +20,6 @@
 (require 'dash)
 (require 'f)
 
-
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Libraries
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -111,6 +110,22 @@ difficult to troubleshoot bugs in your init files."
   "Read input from user with PROMPT."
   (read-string prompt))
 
+;; TODO: Fix the bug with tokenizing here, since it will split any whitespace
+;; character, (even though it shouldn't in the case of quoted string in shell).
+;; e.g. - "xmodmap -e 'one two three'" => '("xmodmap" "-e" "'one two three'")
+(cl-defun prelude/start-process (&key name command)
+  "Pass command string, COMMAND, and the function name, NAME.
+This is a wrapper around `start-process' that has an API that resembles
+`shell-command'."
+  (let* ((tokens (string/split " " command))
+         (program-name (list/head tokens))
+         (program-args (list/tail tokens)))
+    (apply #'start-process
+           `(,(string/format "*%s<%s>*" program-name name)
+             ,nil
+             ,program-name
+             ,@program-args))))
+
 (defun prelude/executable-exists? (name)
   "Return t if CLI tool NAME exists according to `exec-path'."
   (let ((file (locate-file name exec-path)))
diff --git a/configs/shared/.emacs.d/wpc/pulse-audio.el b/configs/shared/.emacs.d/wpc/pulse-audio.el
index 87e0c7c5ed30..b81f88c1b098 100644
--- a/configs/shared/.emacs.d/wpc/pulse-audio.el
+++ b/configs/shared/.emacs.d/wpc/pulse-audio.el
@@ -10,6 +10,7 @@
 ;; Dependencies
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+(require 'prelude)
 (require 'string)
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -33,49 +34,35 @@
 (defun pulse-audio/toggle-mute ()
   "Mute the default sink."
   (interactive)
-  (start-process
-   "*pactl<pulse-audio/toggle-mute>*"
-   nil
-   "pactl"
-   "set-sink-mute"
-   "@DEFAULT_SINK@"
-   "toggle")
+  (prelude/start-process
+   :name "pulse-audio/toggle-mute"
+   :command "pactl set-sink-mute @DEFAULT_SINK@ toggle")
   (pulse-audio/message "Mute toggled."))
 
 (defun pulse-audio/toggle-microphone ()
   "Mute the default sink."
   (interactive)
-  (start-process
-   "*pactl<pulse-audio/toggle-mute>*"
-   nil
-   "pactl"
-   "set-source-mute"
-   "@DEFAULT_SOURCE@"
-   "toggle")
+  (prelude/start-process
+   :name "pulse-audio/toggle-microphone"
+   :command "pactl set-source-mute @DEFAULT_SOURCE@ toggle")
   (pulse-audio/message "Microphone toggled."))
 
 (defun pulse-audio/decrease-volume ()
   "Low the volume output of the default sink."
   (interactive)
-  (start-process
-   "*pactl<pulse-audio/toggle-mute>*"
-   nil
-   "pactl"
-   "set-sink-volume"
-   "@DEFAULT_SINK@"
-   (string/format "-%s%%" pulse-audio/step-size))
+  (prelude/start-process
+   :name "pulse-audio/decrease-volume"
+   :command (string/format "pactl set-sink-volume @DEFAULT_SINK@ -%s%%"
+                           pulse-audio/step-size))
   (pulse-audio/message "Volume decreased."))
 
 (defun pulse-audio/increase-volume ()
   "Raise the volume output of the default sink."
   (interactive)
-  (start-process
-   "*pactl<pulse-audio/toggle-mute>*"
-   nil
-   "pactl"
-   "set-sink-volume"
-   "@DEFAULT_SINK@"
-   (string/format "+%s%%" pulse-audio/step-size))
+  (prelude/start-process
+   :name "pulse-audio/increase-volume"
+   :command (string/format "pactl set-sink-volume @DEFAULT_SINK@ +%s%%"
+                           pulse-audio/step-size))
   (pulse-audio/message "Volume increased."))
 
 (when pulse-audio/install-kbds?
diff --git a/configs/shared/.emacs.d/wpc/screen-brightness.el b/configs/shared/.emacs.d/wpc/screen-brightness.el
index 8183196cccbc..715fc7baee35 100644
--- a/configs/shared/.emacs.d/wpc/screen-brightness.el
+++ b/configs/shared/.emacs.d/wpc/screen-brightness.el
@@ -9,6 +9,12 @@
 ;; TODO: Define some isomorphisms. E.g. int->string, string->int.
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Dependencies
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(require 'prelude)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Constants
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
@@ -25,23 +31,17 @@
 (defun screen-brightness/increase ()
   "Increase the screen brightness."
   (interactive)
-  (start-process
-   "*xbacklight<screen-brightness/increase>*"
-   nil
-   "xbacklight"
-   "-inc"
-   (int-to-string screen-brightness/step-size))
+  (prelude/start-process
+   :name "screen-brightness/increase"
+   :command (string/format "xbacklight -inc %s" screen-brightness/step-size))
   (message "[screen-brightness.el] Increased screen brightness."))
 
 (defun screen-brightness/decrease ()
   "Decrease the screen brightness."
   (interactive)
-  (start-process
-   "*xbacklight<screen-brightness/decrease>*"
-   nil
-   "xbacklight"
-   "-dec"
-   (int-to-string screen-brightness/step-size))
+  (prelude/start-process
+   :name "screen-brightness/decrease"
+   :command (string/format "xbacklight -dec %s" screen-brightness/step-size))
   (message "[screen-brightness.el] Decreased screen brightness."))
 
 (when screen-brightness/install-kbds?
diff --git a/configs/shared/.emacs.d/wpc/string.el b/configs/shared/.emacs.d/wpc/string.el
index 9ffe84572af5..1b766f5207a3 100644
--- a/configs/shared/.emacs.d/wpc/string.el
+++ b/configs/shared/.emacs.d/wpc/string.el
@@ -22,11 +22,14 @@
 (defconst string/test? t
   "When t, run the tests.")
 
-;; Strings
 (defun string/hookify (x)
   "Append \"-hook\" to X."
   (s-append "-hook" x))
 
+(defun string/split (y x)
+  "Map string X into a list of strings that were separated by Y."
+  (s-split y x))
+
 (defun string/ensure-hookified (x)
   "Ensure that X has \"-hook\" appended to it."
   (if (s-ends-with? "-hook" x)
diff --git a/configs/shared/.emacs.d/wpc/wallpaper.el b/configs/shared/.emacs.d/wpc/wallpaper.el
index 841fe5428e7a..08758aef09c7 100644
--- a/configs/shared/.emacs.d/wpc/wallpaper.el
+++ b/configs/shared/.emacs.d/wpc/wallpaper.el
@@ -10,6 +10,7 @@
 ;; Dependencies
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+(require 'prelude)
 (require 'fs)
 (require 'cycle)
 (require 'string)
@@ -34,12 +35,9 @@
   "Set computer wallpaper to image at `PATH' using `feh` under-the-hood.
 `PATH' can be absolute or relative since `f-expand' is called in the function
   body to ensure feh can resolve the path."
-  (start-process "*feh<wallpaper/set>*"
-                 nil
-                 "feh"
-                 "--bg-scale"
-                 "--no-feh-bg"
-                 (f-expand path)))
+  (prelude/start-process
+   :name "wallpaper/set"
+   :command (string/format "feh --bg-scale --no-feh-bg %s" (f-expand path))))
 
 (defun wallpaper/whitelist-set (wallpaper)
   "Focuses the WALLPAPER in the `wallpaper/whitelist' cycle."