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MakeMethods::CompositeUsersContributed Perl DocMakeMethods::Composite::Hash(3)

NAME
       Class::MakeMethods::Composite::Hash - Composite hash methods

SYNOPSIS
	 package MyObject;
	 use Class::MakeMethods::Composite::Hash (
	   new => 'new',
	   scalar => [ 'foo', 'bar' ],
	   array => 'my_list',
	   hash	=> 'my_index',
	 );
	 ...

	 my $obj = MyObject->new( foo => 'Foozle' );
	 print $obj->foo();

	 $obj->bar('Barbados');
	 print $obj->bar();

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

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

DESCRIPTION
       The Composite::Hash suclass of MakeMethods provides a basic constructor
       and accessors for blessed-hash object instances.

   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.

       You can also omit the arguments to "use"	and instead make methods at
       runtime by passing the declarations to a	subsequent call	to "make()".

       You may include any number of declarations in each call to "use"	or
       "make()". If methods with the same name already exist, earlier calls to
       "use" or	"make()" win over later	ones, but within each call, later
       declarations superceed earlier ones.

       You can install methods in a different package by passing "-TargetClass
       => package" as your first arguments to "use" or "make".

       See Class::MakeMethods for more details.

   Class::MakeMethods::Basic Declaration Syntax
       The following types of Basic declarations are supported:

       o   generator_type => "method_name"

       o   generator_type => "name_1 name_2..."

       o   generator_type => [ "name_1", "name_2", ...]

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

       For each	method name you	provide, a subroutine of the indicated type
       will be generated and installed under that name in your module.

       Method names should start with a	letter,	followed by zero or more
       letters,	numbers, or underscores.

   Class::MakeMethods::Composite Declaration Syntax
       The Composite syntax also provides several ways to optionally associate
       a hash of additional parameters with a given method name.

       o   generator_type => [ "name_1"	=> { param=>value... },	... ]

	   A hash of parameters	to use just for	this method name.

	   (Note: to prevent confusion with self-contained definition hashes,
	   described below, parameter hashes following a method	name must not
	   contain the key 'name'.)

       o   generator_type => [ [ "name_1", "name_2", ... ] => {
	   param=>value... } ]

	   Each	of these method	names gets a copy of the same set of
	   parameters.

       o   generator_type => [ { "name"=>"name_1", param=>value... }, ... ]

	   By including	the reserved parameter "name", you create a self-
	   contained declaration with that name	and any	associated hash
	   values.

       Basic declarations, as described	above, are given an empty parameter
       hash.

METHOD GENERATOR TYPES
   new - Constructor
       For each	method name passed, returns a subroutine with the following
       characteristics:

       o   Has a reference to a	sample item to copy. This defaults to a
	   reference to	an empty hash, but you may override this with the
	   "'defaults' => hash_ref"  method parameter.

       o   If called as	a class	method,	makes a	new hash and blesses it	into
	   that	class.

       o   If called on	a hash-based instance, makes a copy of it and blesses
	   the copy into the same class	as the original	instance.

       o   If passed a list of key-value pairs,	appends	them to	the new	hash.
	   These arguments override any	copied values, and later arguments
	   with	the same name will override earlier ones.

       o   Returns the new instance.

       Sample declaration and usage:

	 package MyObject;
	 use Class::MakeMethods::Composite::Hash (
	   new => 'new',
	 );
	 ...

	 # Bare	constructor
	 my $empty = MyObject->new();

	 # Constructor with initial values
	 my $obj = MyObject->new( foo => 'Foozle', bar => 'Barbados' );

	 # Copy	with overriding	value
	 my $copy = $obj->new( bar => 'Bob' );

   new --with_values - Constructor
       For each	method name passed, returns a subroutine with the following
       characteristics:

       o   May be called as a class method, or (equivalently) on any existing
	   object of that class.

       o   Creates a hash, blesses it into the class, and returns the new
	   instance.

       o   If no arguments are provided, the returned hash will	be empty. If
	   passed a single hash-ref argument, copies its contents into the new
	   hash. If called with	multiple arguments, treats them	as key-value
	   pairs, and copies them into the new hash. (Note that	this is	a
	   "shallow" copy, not a "deep"	clone.)

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

       o   Must	be called on a hash-based instance.

       o   Has a specific hash key to use to access the	related	value for each
	   instance.  This defaults to the method name,	but you	may override
	   this	with the "'hash_key' ="	string>	method parameter.

       o   If called without any arguments returns the current value.

       o   If called with an argument, stores that as the value, 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 MyObject;
	 use Class::MakeMethods::Composite::Hash (
	   scalar => 'foo',
	 );
	 ...

	 # Store value
	 $obj->foo('Foozle');

	 # Retrieve value
	 print $obj->foo;

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

       o   Must	be called on a hash-based instance.

       o   Has a specific hash key to use to access the	related	value for each
	   instance.  This defaults to the method name,	but you	may override
	   this	with the "'hash_key' ="	string>	method parameter.

       o   The value for each instance 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 instance's 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 MyObject;
	 use Class::MakeMethods::Composite::Hash (
	   array => 'bar',
	 );
	 ...

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

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

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

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

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

       There are also calling conventions for slice and	splice operations:

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

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

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

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

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

       o   Must	be called on a hash-based instance.

       o   Has a specific hash key to use to access the	related	value for each
	   instance.  This defaults to the method name,	but you	may override
	   this	with the "'hash_key' ="	string>	method parameter.

       o   The value for each instance 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 (or undef).

       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).

       o   If called with one array-ref	argument, uses the contents of that
	   array to retrieve a slice of	the referenced hash.

       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	referenced hash. If the	instance's value was
	   previously undefined, a new hash is autovivified. 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 MyObject;
	 use Class::MakeMethods::Composite::Hash (
	   hash	=> 'baz',
	 );
	 ...

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

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

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

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

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

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

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

       o   Must	be called on a hash-based instance.

       o   Has a specific hash key to use to access the	related	value for each
	   instance.  This defaults to the method name,	but you	may override
	   this	with the "'hash_key' ="	string>	method parameter.

       o   The value for each instance will be a reference to an object	(or
	   undef).

       o   If called without any arguments returns the current value.

       o   If called with an argument, stores that as the value, and returns
	   it,

       Sample declaration and usage:

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

	 # Store value
	 $obj->foo( Foozle->new() );

	 # Retrieve value
	 print $obj->foo;

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

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

perl v5.24.1			  2004-09-06   MakeMethods::Composite::Hash(3)

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

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