Character class question

[bluethundr]

Hey folks,

New to perl, new to perlmonks. But this time I am motivated enough to believe that I'll finally get a handle on the beast! Dare I say I _love_ learning regular expressions?

Okay before I get too verbose, I should say that I believe (not sure) I'm using 5.6.1. (tried manning to find perl version, but no luck - also checked perlfaq). The book I am learning from is Laura Lemay's "Perl In 21 Days" by sams. The code example is one I entered by hand from the book and it can be found in the "Day 9" lesson.

I have stared at this code 'till my eyes started bleeding and I think I need a fresh pair (hopefully those of a perlmonk) to help me figure this one out.

The code that's troubling me in specific is this:

elsif (/[W_]/) { # other chars
                  print "huh? That *really* doesn't look like a number
+\n";
              }

Which should print out the annoying message in the print command. It does not. I know not why. Otherwise, it compiles and works "fine". I could whine about the things I tried, but I'm trying (unsuccessfully) to keep this short.

The script is as follows:

#!/usr/bin/perl -w
# number speller: prints out word approximations of numbers
# simple version, only does single digits

$exit = "";  # whether or not to exit the script

while ($exit ne "n") {

    while () {
         print 'Enter the number you would like to spell (0-9): ';
         chomp($_ = <STDIN>);
         if (/^\d$/) {
             print "Thanks!\n";
             last;
         } elsif (/^$/) {
              print "You didn't enter anything.\n";
         } elsif (/\D/) {  # nonnumbers
             if (/[a-zA-Z]/) { # letters
                 print "You can't fool me. There are letters in there.
+\n";
              } elsif (/^-\d/) { # negative numbers
                  print "That's a negative number. Positive only, plea
+se!\n";
              } elsif (/\./) { # decimals
                   print "That looks like it could be a floating point
+ numer.\n";
                   print "I can't spell a floating point number. Try a
+gain.\n";
              } elsif (/[W_]/) { # other chars
                  print "huh? That *really* doesn't look like a number
+\n";
              }
          } elsif ($_ > 9) {
              print "Too big! 0 through 9, please.\n";
          }
    }

    print "Number $_ is ";
    /1/ && print 'one';
    /2/ && print 'two';
    /3/ && print 'three';
    /4/ && print 'four';
    /5/ && print 'five';
    /6/ && print 'six';
    /7/ && print 'seven';
    /8/ && print 'eight';
    /9/ && print 'nine';
    /0/ && print 'zero';
    print "\n";

    while () {
       print 'Try another number (y/n)?: ';
       chomp ($exit = <STDIN>);
       $exit = lc $exit;
       if ($exit =~ /^[yn]/) {
           last;
       }
       else {
           print "y or n, please\n";
       }
    }
}

All of the other options in the while loop that tests the input (using regexes) after the "nonnumbers" test:
} elsif (/\D/) {  # nonnumbers
seem to work fine. It's just that one that's balking? Any ideas? I'm also open to comments about how to post more effectively/better since this is my first EVER post to this site.

THANK YOU!

janitored by ybiC: Retitle from less-than-descriptive "5.6.1 begginner newb question", balanced <readmore> tags around codeblock, minor format tweaks for legibility