commit 79ed446f0b3f923352c048ffc72a49cad53fadf2
from: Omar Polo <op@omarpolo.com>
date: Mon May 09 08:55:49 2022 UTC

+amused-monitor

commit - d55310b3dcbc2ceabf84d9e550d7122d7571e2cf
commit + 79ed446f0b3f923352c048ffc72a49cad53fadf2
blob - /dev/null
blob + 43cc5d546b93f3cb16190484b29a4db29f9672cc (mode 644)
--- /dev/null
+++ bin/amused-monitor.lp
@@ -0,0 +1,91 @@
+# amused-monitor
+
+This is a small interface for the amused music player
+
+=> https://projects.omarpolo.com/amused.html amused
+
+	#!/usr/bin/env rc
+
+It's written in rc because I found easier to manage subprocesses in it
+rather than in sh.
+
+There are two main processes involved: input and ui.  The input
+process handles the keybindings and controls amused, the ui input
+waits for some events and redraws the interface.
+
+	fn input {
+		ifs=()
+
+$ifs needs to be set to the empty list (or empty string), otherwise
+we're not able to read spaces as keybindings.
+
+		run=1
+		while (~ $run 1) {
+
+rc lacks a break statement, so I'm using a flag variable to quit
+looping.
+
+			stty raw
+			t=`{dd bs=1 count=1 status=none}
+			stty cooked
+
+This is just a trick to read without echoing back the characters.
+
+			switch ($"t) {
+			case n
+				amused next
+			case p
+				amused prev
+			case ' '
+				amused toggle
+			case s
+				amused stop
+			case q
+				run=0
+			case *
+				echo unknown keybinding '>'$t'<'
+			}
+		}
+	}
+
+The ui functions render the interface.  I'd like to keep a small xterm
+open, that's why I'm narrowing (with grep -A -B) only to the songs
+around the currently played one.
+
+	fn ui {
+		clear
+		amused show -p | grep -A3 -B3 '^>' | awk '{printf "%s\r\n", $0}'
+
+The awk trick deserves an explanation.  Since the input function is
+very likely running, the terminal is in "raw" mode: we need \r to
+reposition the character at the start of the line.
+
+	}
+
+The uiloop function is the driver for the ui process: it listens to
+interesting events and redraws the ui when they happen
+
+	fn uiloop {
+		amused monitor | egrep --line-buffered 'next|prev|pause' | {
+			while (read) {
+				ui
+			}
+
+A small note of merit: unlike other shells read is not a built in in
+rc bur rather an external command (/usr/local/plan9/bin/read here.)
+
+		}
+	}
+
+And that's all.  I only need to launch the functions in the correct
+order and do one render at the start and amused-monitor is done!
+
+	ui
+	uiloop &
+	uipid=$apid
+	input
+	kill -INT -$uipid
+
+
+
+
blob - 8b9897df2dd0100aea8ee8901b07a045bbe208f3
blob + df3e8e76b5eab8dbbd629db606de181060b0d444
--- gen
+++ gen
@@ -64,6 +64,7 @@ pair .psqlrc		psqlrc.lp
 pair .cwmrc		cwmrc.lp
 
 pair bin/acmerc		bin/acmerc.lp	+x
+pair bin/amused-monitor	bin/amused-monitor.lp +x
 pair bin/browser	bin/browser.lp	+x
 pair bin/sshot		bin/sshot.lp	+x