use strict;

sub nextline {
    my $fh = shift;
    return sub {
        return scalar <$fh>;
    }
}

open(FOO, "somefile.txt") or die("Doh - $!");

my $nl = nextline(*FOO{IO});
print $nl->() for 0..3;

close(FOO);

__END__

=INPUT
foo
bar
baz
quux
xxx
yy
z

=OUTPUT
foo
bar
baz
quux