package Mapx;

use strict;
use warnings;

use Exporter qw( import );
our @EXPORT = qw( mapx DONE_MAP );

use Scalar::Util qw( reftype blessed );

use constant DONE_MAP => \&mapx;

sub mapx(&@) {
   my $cb = shift;
   my @rv;
   for (@_) {
      my @x = $cb->();
      last if @x == 1 && reftype($x[0]) && !blessed($x[0]) && $x[0] == DONE_MAP;
      push @rv, @x;
   }
   return @rv;
}

1;

##</code><code>##

use strict;
use warnings;
use 5.010;

use Mapx;

sub x {
    my $target = shift;
    mapx {
         return DONE_MAP if $_ == $target;
         $_
    } @_;
}

say for x( 5, 1..9 );