use strict;
use warnings;

my $var = 'foo';

my $tmp;
$var = ( $tmp = return_false() ) ? $tmp : $var;

print "$var\n";

$var = ( $tmp = return_true() ) ? $tmp : $var;

print "$var\n";


sub return_true
{
    return 'bar';
}

sub return_false
{
    return;
}