#! perl -slw
use strict;

sub map2 (&@) {
	use Carp;
	my $code = shift;
	croak 'Odd number of values in list' if @_ & 1;
	map { local ($a, $b) = (shift,shift); $code->() } 1 .. (@_>>1);
}

#! This works.
my @array = ('A'..'J');
map2{ print "$a $b"; } @array;

=pod This code gives compile time error.

map2{ print "$a $b"; } qw[A B C D];

C:\test>test
Type of arg 1 to main::map2 must be block or sub {} (not list) at C:\test\test.pl line 17, near "qw[A B C D];"
Execution of C:\test\test.pl aborted due to compilation errors.

=cut

#! But this works fine??
map{ print $_; } qw[A B C D];