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+=head1 NAME
+
+Class::MakeMethods::Utility::Inheritable - "Inheritable" data
+
+
+=head1 SYNOPSIS
+
+ package MyClass;
+ sub new { ... }
+
+ package MySubclass;
+ @ISA = 'MyClass';
+ ...
+ my $obj = MyClass->new(...);
+ my $subobj = MySubclass->new(...);
+
+ use Class::MakeMethods::Utility::Inheritable qw(get_vvalue set_vvalue );
+
+ my $dataset = {};
+ set_vvalue($dataset, 'MyClass', 'Foobar'); # Set value for class
+ get_vvalue($dataset, 'MyClass'); # Gets value "Foobar"
+
+ get_vvalue($dataset, $obj); # Objects "inherit"
+ set_vvalue($dataset, $obj, 'Foible'); # Until you override
+ get_vvalue($dataset, $obj); # Now finds "Foible"
+
+ get_vvalue($dataset, 'MySubclass'); # Subclass "inherits"
+ get_vvalue($dataset, $subobj); # As do its objects
+ set_vvalue($dataset, 'MySubclass', 'Foozle'); # Until we override it
+ get_vvalue($dataset, 'MySubclass'); # Now finds "Foozle"
+
+ get_vvalue($dataset, $subobj); # Change cascades down
+ set_vvalue($dataset, $subobj, 'Foolish'); # Until we override again
+
+ get_vvalue($dataset, 'MyClass'); # Superclass is unchanged
+
+=head1 DESCRIPTION
+
+This module provides several functions which allow you to store values in a hash corresponding to both objects and classes, and to retrieve those values by searching a object's inheritance tree until it finds a matching entry.
+
+This functionality is used by Class::MakeMethods::Standard::Inheritable and Class::MakeMethods::Composite::Inheritable to construct methods that can both store class data and be overriden on a per-object level.
+
+=cut
+
+########################################################################
+
+package Class::MakeMethods::Utility::Inheritable;
+
+$VERSION = 1.000;
+
+@EXPORT_OK = qw( get_vvalue set_vvalue find_vself );
+sub import { require Exporter and goto &Exporter::import } # lazy Exporter
+
+use strict;
+
+########################################################################
+
+=head1 REFERENCE
+
+=head2 find_vself
+
+ $vself = find_vself( $dataset, $instance );
+
+Searches $instance's inheritance tree until it finds a matching entry in the dataset, and returns either the instance, the class that matched, or undef.
+
+=cut
+
+sub find_vself {
+ my $dataset = shift;
+ my $instance = shift;
+
+ return $instance if ( exists $dataset->{$instance} );
+
+ my $v_self;
+ my @isa_search = ( ref($instance) || $instance );
+ while ( scalar @isa_search ) {
+ $v_self = shift @isa_search;
+ return $v_self if ( exists $dataset->{$v_self} );
+ no strict 'refs';
+ unshift @isa_search, @{"$v_self\::ISA"};
+ }
+ return;
+}
+
+=head2 get_vvalue
+
+ $value = get_vvalue( $dataset, $instance );
+
+Searches $instance's inheritance tree until it finds a matching entry in the dataset, and returns that value
+
+=cut
+
+sub get_vvalue {
+ my $dataset = shift;
+ my $instance = shift;
+ my $v_self = find_vself($dataset, $instance);
+ # warn "Dataset: " . join( ', ', %$dataset );
+ # warn "Retrieving $dataset -> $instance ($v_self): '$dataset->{$v_self}'";
+ return $v_self ? $dataset->{$v_self} : ();
+}
+
+=head2 set_vvalue
+
+ $value = set_vvalue( $dataset, $instance, $value );
+
+Searches $instance's inheritance tree until it finds a matching entry in the dataset, and returns that value
+
+=cut
+
+sub set_vvalue {
+ my $dataset = shift;
+ my $instance = shift;
+ my $value = shift;
+ if ( defined $value ) {
+ # warn "Setting $dataset -> $instance = $value";
+ $dataset->{$instance} = $value;
+ } else {
+ # warn "Clearing $dataset -> $instance";
+ delete $dataset->{$instance};
+ undef;
+ }
+}
+
+########################################################################
+
+1;