use strict;
use warnings;
use Data::Dumper;

sub mkcref (@) {
   my @closed = @_;
   return sub { @closed};
}

sub mkaref (@) {
   return [@_];
}

sub mkhref (%) {
    if ( @_%2 ) {
        warn "Odd number of elements in mkhref";
        return { @_, undef };
    }
    else {
        return {@_};
    }
}

my $foo = mkaref 1,2,3,qw(a b c);
print Dumper $foo;

my $bar = mkhref a => 1, b => 2,  3;
print Dumper $bar;