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⬅️ Previous capture (2022-06-03)
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This is a small interface for the amused music player
#!/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 *
printf ' unknown keybinding >'$t'<\r'
}
}
}
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", $0}'
The awk trick deserves an explanation. Since the input function is very likely running, the terminal is in "raw" mode: we need \r to reposition the character at the start of the line.
}
The uiloop function is the driver for the ui process: it listens to interesting events and redraws the ui when they happen
fn uiloop {
amused monitor next,prev,jump | {
while (read) {
ui
}
A small note of merit: unlike other shells read is not a built in in rc bur rather an external command (/usr/local/plan9/bin/read here.)
} }
And that's all. I only need to launch the functions in the correct order and do one render at the start and amused-monitor is done!
ui uiloop & uipid=$apid input kill -INT -$uipid