IPC between perl and python using stdin and stdout

child-proc.py

#!/usr/bin/env python3

while 1:
    x = input('')
    if x == 'exit':
        print('exiting...')
        break
    print(x)

output.txt

1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
exiting...

parent-proc.p6

#!/usr/bin/env perl6
use v6;

# instantiate the Proc::Async object
my $proc = Proc::Async.new: 'python3', 'child-proc.py', :w;

# instantiate a channel to store our output
my $chan = Channel.new;

# tap the Supply (stdout and stderr) to send all output to our channel
$proc.Supply.tap: {$chan.send: $_};

# start the proc
my $prom = $proc.start;

# send a bunch of commands to the procs stdin
# and send the command twice to simulate not knowing how much output we get
for 1 .. 10 {
    # using put because it adds a new line and doesn't alter the output
    # not sure if UTF-8 is better or worse than binary (.write)
    $proc.put: $_;
    $proc.put: $_;

    # if we know output is coming we can use .recieve
    # it blocks until something is available in the channel and then removes/returns it
    print $chan.receive; # using print because our output comes with a \n
}

# send the exit command for our sample program
$proc.put: "exit";

# there is still output in our channel we have not read...
# this will loop until we get to something expected
loop {
    if $chan.poll -> $x {
        print $x;
        last if $x.contains('exiting');
    }
}