se warnings;
use strict;

sub create_scheduler {
	my $list = shift;
	return sub {
		my $i = shift;
		return () if $i > $#$list - 1 or $i < 0;
		return ( $list->[$i], $list->[$i+1] );
	}
};

my $leg = create_scheduler [ "Chicago", "Saint Looey", "Joplin", "OKC", "Amarillo", "Gallup", "Flagstaff", "Winona", "Kingman", "Barstow", "San Bernandino", "LA" ];
 
my $i = 0;
while( my @pair = $leg->($i++) ) {
	print join( " to ", @pair ), "\n";
}