Your never make it to the regex test because $min (at least in your code) is a true value and your sanity checks aren't cumulative but mutually exclusive thanks to the if ( $min ) structure.

Perhaps you meant to roll the two ifs into one so that you can fall through to the other tests?

  if ( $min && $len < $min ) # <> 0
  {
     $err .= wes( "$lbl cannot be blank." );
  }
[download]

Also, if you're going to pass a regex like that, it either needs to be done as qr/\W/, sans the slashes, or be evaled so that the slashes aren't treated literally.

You may want to rethink your regex, logic, and error message as they seem to be at odds with another: it should be \w instead of \W (or an if instead of unless), and there prolly ought to be some anchors so that bogus input with a single valid match doesn't pass.

Finally, on reinventing the wheel ... have you looked at HTML::FormValidator? :)

    --k.

I also find your sub arguments a bit confusing. Your 5th is a pattern that you don't want to match, and your 6th is a word description of the pattern you do want to match. This may be leading you to your binary confusion (I get that all the time ;-).

Update: ...and I didn't catch the problem with passing the regex in the first place (/me slaps self and goes to bed)

--
I'd like to be able to assign to an luser

The most obvious problem is your chcking logic. If you want to
sequentially check several things you need:

sub checkit {
    if {}
    if {}
    if {}
  return;
}

not this (which is what you have) 

sub checkit {
    if {}
    elsif {}
    else {}
  return;
}

Your sub exits the if/elsif/else statement if $min is non zero and 
also  $len < $min. BTW: Why you use two ifs here instead of an and
to eval these two conditions is beyond me. This is fixed below:

sub paramCheck
  # Returns "" if no error or description of problem(s).
  {
    my $lbl = shift;  # Field name for error messages
    my $val = shift;  # Value received from the CGI query
    my $min = shift;  # Minimun length; Use >0 for required fields
    my $max = shift;  # Maximum allowed length
    my $pat = shift;  # Regex to validate the data against.
    my $msg = shift;  # Explanation added to error if Regex fails.
    my $err = "";     # Holds error message
    my $len = length( $val );

    if ( $min and $len < $min ) {
       { $err .= wes( "$lbl cannot be blank." ); }
    }
    if ( $len > $max ) { 
       my $s = $len == 1 ? "" : "s";
       $err .= wes( "$lbl is currently $len character$s; " . 
                    "; it can only be $max character$s long." );
    }
    if ( $val !~ $pat ) { 
        $err .= wes( "$lbl contains invalid characters; " . 
                     "it can only hold $msg." );
    }
  return $err;
}

I assume you are assigning $pat as so (it won't work otherwise):

$pat = m/foo/;

Run this if you are unsure of what I am getting at:

$pat = "m/foo/";
print "foo1\n" if "foo" =~ $pat;

$pat = m/foo/;
print "foo2\n" if "foo" =~ $pat;

$pat = qr/foo/;
print "foo3\n" if "foo" =~ m/$pat/;

Passing $pat into a sub is no problem using either of 
the second two methods above. The first does not work
period as you will see if you run it.

happy coding

tachyon
[download]

tachyon compares three methods of assigning regexes to a variable:

$pat = "m/foo/";
print "foo1\n" if "foo" =~ $pat;

$pat = m/foo/;
print "foo2\n" if "foo" =~ $pat;

$pat = qr/foo/;
print "foo3\n" if "foo" =~ m/$pat/;
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Passing $pat into a sub is no problem using either of the second two methods above. The first does not work period as you will see if you run it.

The second does not work either. It is equivalent to:

$pat = ($_ =~ m/foo/);
print "foo2\n" if "foo" =~ $pat;
[download]

$pat will be either 1 or the null string, depending on whether $_ matches /foo/. You will see this if you run it and actually examine the value of $pat.

Dang, you are correct! I never write $foo =~ $pat so as the
seeker of wisdom needed to be using this construct I *quickly*
checked it to see if it worked using the code posted.

As you rightly point out although this appeared to work
in my quick test if I had also tested this:

$pat = m/foo/;
print "big snafu, egg on face, whoops\n" if "bar" =~ $pat;

then my error would have stared me in the face! Thanks for
pointing out the error, I hate to post wrong advice and 
usually run a quick test first. Ah well, another day at the 
monestry, another snippet of wisdom on the road to 
enlightenment.

As a result the original code will need a qr/$pat/ to work.

head bowed, duly chastened :-(

tachyon

PS this is what you need to get it to work. Trust me ;-)

$pat = qr/some pattern here/;
...
...
...

sub paramCheck
  # Returns "" if no error or description of problem(s).
  {
    ...
    my $pat = shift;
    ...
    ...
    if ( $val !~ m/$pat/ ) { 
        $err .= wes( "$lbl contains invalid characters; " . 
                     "it can only hold $msg." );
    }
  return $err;
}
[download]