comment on

To add to these other good examples, take CGI.pm

Often I'll have to generate a select tag (popup_menu) with different key and values. The way to do this in CGI.pm is by passing a hash. Usually you'll want them sorted by the display value, but hashes are intrinsically unordered.

What to do?

Simple

# Kludge to get options sorted.
package MySortHash;
use Tie::Hash;
use vars qw(@ISA);
@ISA = qw( Tie::StdHash );
sub FIRSTKEY {
    my $self = shift;
    @{ $self->{VERY_UNLIKELY_HASH_KEY} } = sort {$self->{$a} cmp $self
+->{$b} } grep { $_ ne 'VERY_UNLIKELY_HASH_KEY' } keys %{$self};
    return shift @{ $self->{VERY_UNLIKELY_HASH_KEY} };
}
sub NEXTKEY {
    my $self = shift;     return shift @{ $self->{VERY_UNLIKELY_HASH_K
+EY} };
}
# later in package main...
tie %thash, 'MySortHash' ;    # tied hash with sorted keys...
print $q->popup_menu(-name=>$p , labels=> \%thash, -values=> [ (keys %
+thash) ]  );
[download]

Now I could subcass CGI and muck around with popup_menu or I could write yet another CGI module but why when I can coax CGI.pm into DWIM with in 10 lines of code? My favorite uses usually are coaxing some new behavior out of existing code. Paging/Filtering filehandles.. etc.

-Lee

"To be civilized is to deny one's nature."

In reply to Re: Tied Variables - why? by shotgunefx
in thread Tied Variables - why? by samurai

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