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P5tie cpan:ELIZABETH last updated on 2018-04-11


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P5tie - Implement Perl 5's tie() built-in


use P5tie; # exports tie(), tied() and untie()

tie my $s, Tie::AsScalar;
tie my @a, Tie::AsArray;
tie my %h, Tie::AsHash;

$object = tied $s;
untie $s;


This module tries to mimic the behaviour of the tie of Perl 5 as closely as possible. Please note that there are usually better ways attaching special functionality to arrays, hashes and scalars in Perl 6 than using tie. Please see the documentation on Custom Types for more information to handling the needs that Perl 5's tie fulfills in a more efficient way in Perl 6.


Subs versus Methods

In Rakudo Perl 6, the special methods of the tieing class, can be implemented as Perl 6 methods, or they can be implemented as our subs, both are perfectly acceptable. They can even be mixed, if necessary. But note that if you're depending on subclassing, that you must change the package to a class to make things work.


Because Rakudo Perl 6 does not have the concept of magic that can be added or removed, it is not possible to untie a variable. Note that the associated UNTIE sub/method will be called, so that any resources can be freed.

Potentially it would be possible to actually have any subsequent accesses to the tied variable throw an exception: perhaps it will at some point.

Scalar variable tying versus Proxy

Because tying a scalar in Rakudo Perl 6 must be implemented using a Proxy, and it is currently not possible to mix in any additional behaviour into a Proxy, it is alas impossible to implement UNTIE and DESTROY for tied scalars at this point in time. Please note that UNTIE and DESTROY are supported for tied arrays and hashes.

Tieing a file handle

Tieing a file handle is not yet implemented at this time. Mainly because I don't grok yet how to do that. As usual, patches and Pull Requests are welcome!


Elizabeth Mattijsen

Source can be located at: . Comments and Pull Requests are welcome.


Copyright 2018 Elizabeth Mattijsen

Re-imagined from Perl 5 as part of the CPAN Butterfly Plan.

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.