The InstanceFlyweightPattern is an extreme form of the FlyweightPattern.

* Name:  InstanceFlyweightPattern
* Classification: I have no clue.
* Motivation: 
* Applicability: Replacing value types with immutable reference types while saving memory.
* Structure: ?
* Participants: ?
* Collaborations: ?
* Consequences: Decrease on memory usage; however, some calculations might become harder because of the inability to directly manipulate new instances as an optimization.
* Implementation:  Memoize the 'new' method!
* Sample Code:
    #!/usr/bin/env perl
    package Integer;
    { my %ints;
     sub new {
        my $class = shift;
        my $self;
        unless(exists($self = $ints{$_[0]})){
             $self = bless {'int' => $_[0]}, $class;
        }
        $self;
     }
    }
* Known Uses:  Numeric types come to mind.
* Related Patterns:  ReverseFlyweightPattern, FlyweightPattern, SingletonPattern
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CategoryPattern