use strict;
use Text::ParseWords;

my $string = 'one "two and a half" "three"  four "five" "six"';

my @words = &parse_line('\s+', 1, $string);
my $error = length($string) && @words == 0;

my @unquoted = grep {!m/"/} @words;
my @quoted = grep {s/^"(.*)"$/$1/} @words;

print join('|', @unquoted)."\n";
print join('|', @quoted)."\n";
print $error;