#!/usr/bin/perl
use strict;
use warnings;
use diagnostics;


use IPC::Open3;
use IO::Select;

my @answers = qw/galahad seekthegrail bluenored!/;

my( $wtr, $rdr, $err );
use Symbol 'gensym';
$err = gensym;
my $pid = open3( $wtr, $rdr, $err, 'server.pl' );

print "IN: $wtr     OUT: $rdr     ERR: $err\n";
print "PID was $pid\n";

my $sel = new IO::Select;
$sel->add( $wtr, $rdr );

my $line;
foreach my $readhandle ( $sel->can_read(1) ) {
    print "readhandle is $readhandle \n";
    next if $readhandle != $rdr;
    print "past next\n";
    my $len = sysread $readhandle, $line, 4096;
    if( not defined $len ) {
        die "Error from child: $!\n";
    }

    print $line;
    write_answers();


}

waitpid( $pid, 0 );


sub write_answers {

    foreach my $writehandle ( $sel->can_write ) {
        print "write handle is $writehandle\n";
        return if $writehandle != $wtr;
        my $answer = shift @answers;
        print "writing $answer\n";
        print $writehandle $answer . "\n";
    }
}