Aspect::Library::Singleton - A singleton aspect

       Adam Kennedy <adamk@cpan.org>

       Marcel Grünauer <marcel@cpan.org>

       Ran Eilam <eilara@cpan.org>

       Copyright 2001 by Marcel Grünauer

       Some parts copyright 2009 - 2013 Adam Kennedy.

       This  library  is  free  software;  you can redistribute it and/or modify it under the same terms as Perl
       itself.

perl v5.36.0                                       2023-07-02                    Aspect::Library::Singleton(3pm)

       A reusable aspect that forces singleton behavior on a constructor. The constructor is defined by a
       pointcut spec: a string. regexp, or code ref.

       It is slightly different from "Class::Singleton"
       (<http://search.cpan.org/~abw/Class-Singleton/Singleton.pm>):

       •   No specific name requirement on the constructor for the external interface, or for the implementation
           ("Class::Singleton"    requires    clients   use   "instance()",   and   that   subclasses   override
           "_new_instance()"). With aspects, you can change the cardinality of your objects without changing the
           clients, or the objects themselves.

       •   No need to inherit from anything- use pointcuts to specify the  constructors  you  want  to  memoize.
           Instead of pulling singleton behavior from a base class, you are pushing it in, using the aspect.

       •   No package variable or method is added to the callers namespace

       Note that this is just a special case of memoizing.

       Aspect::Library::Singleton - A singleton aspect

         use Aspect;
         use Aspect::Singleton;

         aspect Singleton => 'Foo::new';

         my $f1 = Foo->new;
         my $f2 = Foo->new;

         # Both $f1 and $f2 refer to the same object