Tie::Util - Utility functions for fiddling with tied variables
Version 0.01
This is a beta version. If you could please test it and report any bugs (via e-mail), I would be grateful.
use Tie::Util; use Tie::RefHash; tie %hash, 'Tie::RefHash'; $obj = tied %hash; tie %another_hash, to => $obj; # two hashes now tied to the same object is_tied %hash; # returns true $obj = weak_tie %hash3, 'Tie::RefHash'; # %hash3 now holds a weak reference to the Tie::RefHash object. weaken_tie %another_hash; # weaken an existing tie is_weak_tie %hash3; # returns true is_weak_tie %hash; # returns false but defined is_weak_tie %hash4; # returns undef (not tied)
This module provides a few subroutines for examining and modifying tied variables, including those that hold weak references to the objects to which they are tied (weak ties).
It also provides tie constructors in the to:: namespace, so that you can tie variables to existing objects, like this:
tie $var, to => $obj; weak_tie @var, to => $another_obj; # for a weak tie
All the following functions are exported by default. You can choose to import only a few, with use Tie::Util qw'is_tied weak_tie', or none at all, with use Tie::Util().
Similar to the built-in tied function, but it returns a simple scalar.
With this function you don't have to worry about whether the object to which a variable is tied overloads its booleanness (like JE::Boolean et al.), so you can simply write is_tied instead of defined tied.
Furthermore, it will still return true if it is a weak tie that has gone stale (the object to which it was tied [without holding a reference count] has lost all other references, so the variable is now tied to undef), whereas tied returns undef in such cases.
Like tie, this calls $package's tie constructor, passing it the @args, and ties the variable to the returned object. But the tie that it creates is a weak one, i.e., the tied variable does not hold a reference count on the object.
This turns an existing tie into a weak one.
Returns a defined true or false, indicating whether a tied variable is weakly tied. Returns undef if the variable is not tied.
perl 5.8.3 or later
To report bugs, please e-mail the author.
Copyright (C) 2007 Father Chrysostomos <sprout [at] cpan [dot] org>
This program is free software; you may redistribute it and/or modify it under the same terms as perl.
The tie and tied functions in the perlfunc man page.
The perltie man page.
Scalar::Util's weaken function
The B module.
Data::Dumper::Streamer, for which I wrote two of these functions.
