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MakeMethods::CompositeUserhContributed PMakeMethods::Composite::Inheritable(3)

NAME
       Class::MakeMethods::Composite::Inheritable - Overridable	data

SYNOPSIS
	 package MyClass;

	 use Class::MakeMethods( 'Composite::Inheritable:scalar' => 'foo' );
	 # We now have an accessor method for an "inheritable" scalar value

	 MyClass->foo( 'Foozle'	);   # Set a class-wide	value
	 print MyClass->foo();	     # Retrieve	class-wide value

	 my $obj = MyClass->new(...);
	 print $obj->foo();	     # All instances "inherit" that value...

	 $obj->foo( 'Foible' );	     # until you set a value for an instance.
	 print $obj->foo();	     # This now	finds object-specific value.
	 ...

	 package MySubClass;
	 @ISA =	'MyClass';

	 print MySubClass->foo();    # Intially	same as	superclass,
	 MySubClass->foo('Foobar');  # but overridable per subclass,
	 print $subclass_obj->foo(); # and shared by its instances
	 $subclass_obj->foo('Fosil');# until you override them...
	 ...

	 # Similar behaviour for hashes	and arrays is currently	incomplete
	 package MyClass;
	 use Class::MakeMethods::Composite::Inheritable	(
	   array => 'my_list',
	   hash	=> 'my_index',
	 );

	 MyClass->my_list(0 => 'Foozle', 1 => 'Bang!');
	 print MyClass->my_list(1);

	 MyClass->my_index('broccoli' => 'Blah!', 'foo'	=> 'Fiddle');
	 print MyClass->my_index('foo');

DESCRIPTION
       The MakeMethods subclass	provides accessor methods that search an
       inheritance tree	to find	a value. This allows you to set	a shared or
       default value for a given class,	optionally override it in a subclass,
       and then	optionally override it on a per-instance basis.

       Note that all MakeMethods methods are inheritable, in the sense that
       they work as expected for subclasses. These methods are different in
       that the	data accessed by each method can be inherited or overridden in
       each subclass or	instance. See "
       Class::MakeMethods::Utility::Inheritable" for more about	this type of
       "inheritable" or	overridable" data.

   Class::MakeMethods Calling Interface
       When you	"use" this package, the	method declarations you	provide	as
       arguments cause subroutines to be generated and installed in your
       module.

       See "Calling Conventions" in Class::MakeMethods::Standard for more
       information.

   Class::MakeMethods::Standard	Declaration Syntax
       To declare methods, pass	in pairs of a method-type name followed	by one
       or more method names.

       See the "METHOD GENERATOR TYPES"	section	below for a list of the
       supported values	of generator_type.

       See "Declaration	Syntax"	in Class::MakeMethods::Standard	and "Parameter
       Syntax" in Class::MakeMethods::Standard for more	information.

METHOD GENERATOR TYPES
   scalar - Overrideable Accessor
       For each	method name passed, uses a closure to generate a subroutine
       with the	following characteristics:

       o   May be called as a class or instance	method,	on the declaring class
	   or any subclass.

       o   If called without any arguments returns the current value for the
	   callee. If the callee has not had a value defined for this method,
	   searches up from instance to	class, and from	class to superclass,
	   until a callee with a value is located.

       o   If called with an argument, stores that as the value	associated
	   with	the callee, whether instance or	class, and returns it,

       o   If called with multiple arguments, stores a reference to a new
	   array with those arguments as contents, and returns that array
	   reference.

       Sample declaration and usage:

	 package MyClass;
	 use Class::MakeMethods::Composite::Inheritable	(
	   scalar => 'foo',
	 );
	 ...

	 # Store value
	 MyClass->foo('Foozle');

	 # Retrieve value
	 print MyClass->foo;

   array - Overrideable	Ref Accessor
       For each	method name passed, uses a closure to generate a subroutine
       with the	following characteristics:

       o   May be called as a class method, or on any instance or subclass,
	   Must	be called on a hash-based instance.

       o   The class value will	be a reference to an array (or undef).

       o   If called without any arguments, returns the	current	array-ref
	   value (or undef).

       o   If called with a single non-ref argument, uses that argument	as an
	   index to retrieve from the referenced array,	and returns that value
	   (or undef).

       o   If called with a single array ref argument, uses that list to
	   return a slice of the referenced array.

       o   If called with a list of argument pairs, each with a	non-ref	index
	   and an associated value, stores the value at	the given index	in the
	   referenced array. If	the class value	was previously undefined, a
	   new array is	autovivified. The current value	in each	position will
	   be overwritten, and later arguments with the	same index will
	   override earlier ones. Returns the current array-ref	value.

       o   If called with a list of argument pairs, each with the first	item
	   being a reference to	an array of up to two numbers, loops over each
	   pair	and uses those numbers to splice the value array.

	   The first controlling number	is the position	at which the splice
	   will	begin. Zero will start before the first	item in	the list.
	   Negative numbers count backwards from the end of the	array.

	   The second number is	the number of items to be removed from the
	   list. If it is omitted, or undefined, or zero, no items are
	   removed. If it is a positive	integer, that many items will be
	   returned.

	   If both numbers are omitted,	or are both undefined, they default to
	   containing the entire value array.

	   If the second argument is undef, no values will be inserted;	if it
	   is a	non-reference value, that one value will be inserted; if it is
	   an array-ref, its values will be copied.

	   The method returns the items	that removed from the array, if	any.

       Sample declaration and usage:

	 package MyClass;
	 use Class::MakeMethods::Composite::Inheritable	(
	   array => 'bar',
	 );
	 ...

	 # Clear and set contents of list
	 print MyClass->bar([ 'Spume', 'Frost' ] );

	 # Set values by position
	 MyClass->bar(0	=> 'Foozle', 1 => 'Bang!');

	 # Positions may be overwritten, and in	any order
	 MyClass->bar(2	=> 'And	Mash', 1 => 'Blah!');

	 # Retrieve value by position
	 print MyClass->bar(1);

	 # Direct access to referenced array
	 print scalar @{ MyClass->bar()	};

       There are also calling conventions for slice and	splice operations:

	 # Retrieve slice of values by position
	 print join(', ', MyClass->bar(	undef, [0, 2] )	);

	 # Insert an item at position in the array
	 MyClass->bar([3], 'Potatoes' );

	 # Remove 1 item from position 3 in the	array
	 MyClass->bar([3, 1], undef );

	 # Set a new value at position 2, and return the old value
	 print MyClass->bar([2,	1], 'Froth' );

       NOTE: THIS METHOD GENERATOR HAS NOT BEEN	WRITTEN	YET.

   hash	- Overrideable Ref Accessor
       For each	method name passed, uses a closure to generate a subroutine
       with the	following characteristics:

       o   May be called as a class method, or on any instance or subclass,
	   Must	be called on a hash-based instance.

       o   The class value will	be a reference to a hash (or undef).

       o   If called without any arguments returns the contents	of the hash in
	   list	context, or a hash reference in	scalar context for the callee.
	   If the callee has not had a value defined for this method, searches
	   up from instance to class, and from class to	superclass, until a
	   callee with a value is located.

       o   If called with one non-ref argument,	uses that argument as an index
	   to retrieve from the	referenced hash, and returns that value	(or
	   undef). If the callee has not had a value defined for this method,
	   searches up from instance to	class, and from	class to superclass,
	   until a callee with a value is located.

       o   If called with one array-ref	argument, uses the contents of that
	   array to retrieve a slice of	the referenced hash. If	the callee has
	   not had a value defined for this method, searches up	from instance
	   to class, and from class to superclass, until a callee with a value
	   is located.

       o   If called with one hash-ref argument, sets the contents of the
	   referenced hash to match that provided.

       o   If called with a list of key-value pairs, stores the	value under
	   the given key in the	hash associated	with the callee, whether
	   instance or class. If the callee did	not previously have a hash-ref
	   value associated with it, searches up instance to class, and	from
	   class to superclass,	until a	callee with a value is located,	and
	   copies that hash before making the assignments. The current value
	   under each key will be overwritten, and later arguments with	the
	   same	key will override earlier ones.	Returns	the contents of	the
	   hash	in list	context, or a hash reference in	scalar context.

       Sample declaration and usage:

	 package MyClass;
	 use Class::MakeMethods::Composite::Inheritable	(
	   hash	=> 'baz',
	 );
	 ...

	 # Set values by key
	 MyClass->baz('foo' => 'Foozle', 'bar' => 'Bang!');

	 # Values may be overwritten, and in any order
	 MyClass->baz('broccoli' => 'Blah!', 'foo' => 'Fiddle');

	 # Retrieve value by key
	 print MyClass->baz('foo');

	 # Retrive slice of values by position
	 print join(', ', MyClass->baz(	['foo',	'bar'] ) );

	 # Direct access to referenced hash
	 print keys %{ MyClass->baz() };

	 # Reset the hash contents to empty
	 @{ MyClass->baz() } = ();

       NOTE: THIS METHOD GENERATOR IS INCOMPLETE.

   hook	- Overrideable array of	subroutines
       A hook method is	called from the	outside	as a normal method. However,
       internally, it contains an array	of subroutine references, each of
       which are called	in turn	to produce the method's	results.

       Subroutines may be added	to the hook's array by calling it with a
       blessed subroutine reference, as	shown below. Subroutines may be	added
       on a class-wide basis or	on an individual object.

       You might want to use this type of method to provide an easy way	for
       callbacks to be registered.

	 package MyClass;
	 use Class::MakeMethods::Composite::Inheritable	( 'hook' => 'init' );

	 MyClass->init(	Class::MakeMethods::Composite::Inheritable->Hook( sub {
	     my	$callee	= shift;
	     warn "Init...";
	 } );

	 my $obj = MyClass->new;
	 $obj->init();

   object - Overrideable Ref Accessor
       For each	method name passed, uses a closure to generate a subroutine
       with the	following characteristics:

       o   May be called as a class method, or on any instance or subclass,
	   Must	be called on a hash-based instance.

       o   The class value will	be a reference to an object (or	undef).

       o   If called without any arguments returns the current value for the
	   callee. If the callee has not had a value defined for this method,
	   searches up from instance to	class, and from	class to superclass,
	   until a callee with a value is located.

       o   If called with an argument, stores that as the value	associated
	   with	the callee, whether instance or	class, and returns it,

       Sample declaration and usage:

	 package MyClass;
	 use Class::MakeMethods::Composite::Inheritable	(
	   object => 'foo',
	 );
	 ...

	 # Store value
	 MyClass->foo( Foozle->new() );

	 # Retrieve value
	 print MyClass->foo;

       NOTE: THIS METHOD GENERATOR HAS NOT BEEN	WRITTEN	YET.

SEE ALSO
       See Class::MakeMethods for general information about this distribution.

       See Class::MakeMethods::Composite for more about	this family of
       subclasses.

POD ERRORS
       Hey! The	above document had some	coding errors, which are explained
       below:

       Around line 49:
	   L<> starts or ends with whitespace

perl v5.24.1			  2004-0MakeMethods::Composite::Inheritable(3)

NAME | SYNOPSIS | DESCRIPTION | METHOD GENERATOR TYPES | SEE ALSO | POD ERRORS

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