I'm no authority on tied objects, or on overload ... but i think you are confussing the two.

By overloading 'bool' in your package, you can define the behavior of evaluating an object of that package in boolean context -- but I don't think that's what is happening in your code.

By tieing your obejct as a hash, only the TIE* methods for hashes are ever called on your object. When you say: "if (%hash)" it doesn't matter that you have overloaded 'bool' for your package, all that matters is that you are evaluating a hash in a bolean context, which is 'true' if-and-only-if that hash has any elements.

Consider these modifications to your script (and teh output)...

#!/usr/bin/perl -wl
use strict;

my %hash ;
my $obj = new TiedHash();
tie(%hash , 'TiedHash') ;

print "checking Hash....";
print 'BOOLHASH' if ( %hash );

print "checking Object....";
print 'BOOLOBJ' if ( $obj );

package TiedHash ;

use overload
      'bool' => sub{ print "BOOL"; return 1 ; } ,
      '""' =>   sub{ print "STRING"; return 'tiedhash' ; } ,
      ;
sub TIEHASH { bless({}, __PACKAGE__ ) ;}
sub new { return TIEHASH; }
__END__

checking Hash....
checking Object....
BOOL
BOOLOBJ
[download]

...I'm not sure what methods on your tied hash are getting called when %hash is evaluated in boolean context, but i'm sure if you override all of the TIE* methods, you can figure it out.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.