use strict;

my $seq1 = 'aabcdefg';
my $seq2 = 'aabcdefgabcde';

sub in_sequence
{
    my $str = shift;  # fetch the string value
    my $ok = 1;       # set private variable $ok = 1
    $str =~ m/(.)(.)(??{ $ok = 0 if $2 lt $1; 0 })/;
    return $ok;
}

print "Sequence is ", in_sequence($seq1)?"good":"bad", "\n";
print "Sequence is ", in_sequence($seq2)?"good":"bad", "\n";

##</code><code>##

use strict;

my $seq1 = 'aabcdefg';
my $seq2 = 'aabcdefgabcde';

sub in_sequence_debug
{
    my $str = shift;
    my $ok = 1;
    print "Value of OK is $ok\n";
    $str =~ m/(.)(.)(??{
                     print "$1 - $2 ";
                     if ($2 lt $1) {
                       $ok = 0;
                       print "Not Ok\n"
                     } else {
                       print "Ok\n";
                     };
                     0
                })/;
    print "Value of OK is $ok\n";
    return $ok;
}

print "Sequence is ", in_sequence_debug($seq1)?"good":"bad", "\n";
print "-"x40, "\n";
print "Sequence is ", in_sequence_debug($seq2)?"good":"bad", "\n";

##</code><code>##

Value of OK is 1
a - a Ok
a - b Ok
b - c Ok
c - d Ok
d - e Ok
e - f Ok
f - g Ok
Value of OK is 1
Sequence is good
----------------------------------------
Value of OK is 1
a - a Ok
a - b Ok
b - c Ok
c - d Ok
d - e Ok
e - f Ok
f - g Ok
g - a Not Ok
a - b Ok
b - c Ok
c - d Ok
d - e Ok
Value of OK is 1
Sequence is good

##</code><code>##

use strict;

my $seq1 = 'aabcdefg';
my $seq2 = 'aabcdefgabcde';
my $ok; # moved up to the file scope

sub in_sequence_debug
{
    my $str = shift;
    $ok = 1;
    print "Value of OK is $ok\n";
    $str =~ m/(.)(.)(??{
                     print "$1 - $2 ";
                     if ($2 lt $1) {
                       $ok = 0;
                       print "Not Ok\n"
                     } else {
                       print "Ok\n";
                     };
                     0
                })/;
    print "Value of OK is $ok\n";
    return $ok;
}

print "Sequence is ", in_sequence_debug($seq1)?"good":"bad", "\n";
print "-"x40, "\n";
print "Sequence is ", in_sequence_debug($seq2)?"good":"bad", "\n";

##</code><code>##

Value of OK is 1
a - a Ok
a - b Ok
b - c Ok
c - d Ok
d - e Ok
e - f Ok
f - g Ok
Value of OK is 1
Sequence is good
----------------------------------------
Value of OK is 1
a - a Ok
a - b Ok
b - c Ok
c - d Ok
d - e Ok
e - f Ok
f - g Ok
g - a Not Ok
a - b Ok
b - c Ok
c - d Ok
d - e Ok
Value of OK is 0
Sequence is bad