https://github.com/schwern/object-id

A universal object identifier
https://github.com/schwern/object-id

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A universal object identifier

• Host: GitHub
• URL: https://github.com/schwern/object-id
• Owner: schwern
• License: other
• Created: 2010-05-01T14:36:05.000Z (over 14 years ago)
• Default Branch: master
• Last Pushed: 2011-09-25T04:50:56.000Z (over 13 years ago)
• Last Synced: 2024-10-29T20:10:34.605Z (3 months ago)
• Language: Perl
• Homepage: http://search.cpan.org/dist/Object-ID
• Size: 167 KB
• Stars: 4
• Watchers: 2
• Forks: 3
• Open Issues: 1
• Metadata Files:
  • Readme: README
  • Changelog: Changes
  • License: LICENSE

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README

        
NAME

    Object::ID - A unique identifier for any object

SYNOPSIS

        package My::Object;

        # Imports the object_id method

        use Object::ID;

DESCRIPTION

    This is a unique identifier for any object, regardless of its type,

    structure or contents. Its features are:

        * Works on ANY object of any type

        * Does not modify the object in any way

        * Does not change with the object's contents

        * Is O(1) to calculate (ie. doesn't matter how big the object is)

        * The id is unique for the life of the process

        * The id is always a true value

USAGE

    Object::ID is a role, rather than inheriting its methods they are

    imported into your class. To make your class use Object::ID, simply "use

    Object::ID" in your class.

        package My::Class;

        use Object::ID;

    Then write your class however you want.

METHODS

    The following methods are made available to your class.

  object_id

        my $id = $object->object_id;

    Returns an identifier unique to the $object.

    The identifier is not related to the content of the object. It is only

    unique for the life of the process. There is no guarantee as to the

    format of the identifier from version to version.

    For example:

        my $obj = My::Class->new;

        my $copy = $obj;

        # This is true, $obj and $copy refer to the same object

        $obj->object_id eq $copy->object_id;

        my $obj2 = My::Class->new;

        # This is false, $obj and $obj2 are different objects.

        $obj->object_id eq $obj2->object_id;

        use Clone;

        my $clone = clone($obj);

        # This is false, even though they contain the same data.

        $obj->object_id eq $clone->object_id;

  object_uuid

        my $uuid = $object->object_uuid

    Like "$object->object_id" but returns a UUID unique to the $object.

    Only works if Data::UUID is installed.

    See Data::UUID for more details about UUID.

FAQ

  Why not just use the object's reference?

    References are not unique over the life of a process. Perl will reuse

    references of destroyed objects, as demonstrated by this code snippet:

        {

            package Foo;

            sub new {

                my $class = shift;

                my $string = shift;

                return bless {}, $class;

            }

        }

        for(1..3) {

            my $obj = Foo->new;

            print "Object's reference is $obj\n";

        }

    This will print, for example, "Object's reference is Foo=HASH(0x803704)"

    three times.

  How much memory does it use?

    Very little.

    Object::ID stores the ID and address of each object you've asked the ID

    of. Once the object has been destroyed it no longer stores it. In other

    words, you only pay for what you use. When you're done with it, you

    don't pay for it any more.

LICENSE

    Copyright 2010, Michael G Schwern .

    This program is free software; you can redistribute it and/or modify it

    under the same terms as Perl itself.

    See 

THANKS

    Thank you to Vincent Pit for coming up with the implementation.