In the first regular expression you're using the '?' operator which says the previous character or group is optional. But you're applying it against the '+' operator which makes no sense, since it means one-or-more.

If instead you group the \S and + together and then apply the '?', you'll see different results:

use warnings;

my @str = ("____\n", "__ __\n", "__X __\n", "__Z__\n", "__\n__\n", "__
+^__\n");

for(@str) {
   if($_ =~ /__(\S+)?__\n/) {print "1 "}
   else {print "0 "}

   if($_ =~ /__\S+__\n/) {print "1\n"}
   else {print "0\n"}
}
__END__
1 0
0 0
0 0
1 1
0 0
1 1

[download]

So the answer is, Inline.pm just has a bug.

In reply to Re: Puzzled by regex by Loops
in thread Puzzled by regex by syphilis

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