sub from(\$$$){
  my ($ref,$list,$code)=@_;
  return sort{
    $$ref = $a ;
    my $ra = $code->();

    $$ref = $b ;
    my $rb = $code->();

    no warnings;
    $ra <=> $rb or $ra cmp $rb
  }@$list;
}
sub in(\@) { return $_[0]; }
sub order_by(\&) { return $_[0] }