This is something that I like to use a closure for. The following will print a table with all of the URL and HTML codes, along with the symbol each stands for and the extended ASCII value. The $toggle variable controls the background color used for each row of the table.

use CGI;
use HTML::Entities;
use URI::Escape;
my $q = CGI->new;

my $data;
my $toggle    = initToggle( 1 );

for my $ASCII ( 0 .. 255 ) {

    # The following is a hexadecimal list of characters that must be e
+ncoded
    # in query strings
    my $cgi_chars  = '\x00-\x29\x2b\x2c\x2f\x3a-\x40\x5b-\x5e\x60\x7b-
+\xff';

    # The following is a hexadecimal list of characters that often hav
+e their
    # HTML character code equivalent used instead of the characters th
+emselves
    my $html_chars = '\x00-\x2f\x3a-\x40\x5b-\x5e\x60\x7b-\xff';

    my $char      = chr( $ASCII );                         # The actua
+l character
    my $symbol    = encode_entities( $char, $html_chars ); # HTML code
+ for Web page
    my $escaped   = uri_escape( $char, $cgi_chars );       # CGI repre
+sentation
    my $html_code = encode_entities( $symbol );            # Re-encode
+ HTML code so that it
                                                                # disp
+lays properly
    if ( $escaped eq '%20' ) { $escaped .= ' or +' };      # a space m
+ay be %20 or a +
    my @bgcolor   = ( '#FFFFFF', '#CCCCCC' );
    $data .= $q->Tr( { -align   => 'right',
                       -bgcolor => $bgcolor[ &$toggle ] },
                     $q->td( 
                             [ $ASCII < 33 ? '&nbsp;' : $symbol, $ASCI
+I, $escaped, $html_code ] 
                           ) 
                   );
}

print $q->header,
      $q->start_html,
      $q->table( $data ),
      $q->end_html;

sub initToggle {
    my $limit = shift;
    my $count = 0;
    my $bit   = 0;
    unless ( $limit > 0 ) { die "initToggle() requires a positive argu
+ment\n" };
    return sub {
        $bit ^= 1 if $count++ % $limit == 0;
    }
}
[download]

In fact, if you wanted to, you could easily update the closure to return the color values themselves instead of the array index.

Cheers,
Ovid

Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.