Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
MakeMethods::Standard:UseraContributed Perl DocMakeMethods::Standard::Array(3)

NAME
       Class::MakeMethods::Standard::Array - Methods for Array objects

SYNOPSIS
	 package MyObject;
	 use Class::MakeMethods::Standard::Array (
	   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 Standard::Array suclass of MakeMethods provides a basic constructor
       and accessors for blessed-array object instances.

   Calling Conventions
       When you	"use" this package, the	method names you provide as arguments
       cause subroutines to be generated and installed in your module.

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

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

       Valid method-type names for this	package	are listed in "METHOD
       GENERATOR TYPES".

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

   Positional Accessors	and %FIELDS
       Each accessor method is assigned	the next available array index at
       which to	store its value.

       The mapping between method names	and array positions is stored in a
       hash named %FIELDS in the declaring package. When a package declares
       its first positional accessor, its %FIELDS are initialized by searching
       its inheritance tree.

       Warning:	Subclassing packages that use positional accessors is somewhat
       fragile,	since you may end up with two distinct methods assigned	to the
       same position. Specific cases to	avoid are:

       o   If you inherit from more than one class with	positional accessors,
	   the positions used by the two sets of methods will overlap.

       o   If your superclass adds additional positional accessors after you
	   declare your	first, they will overlap yours.

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 array,	but you	may override this with the
	   "'defaults' =" array_ref> method parameter.

       o   If called as	a class	method,	makes a	new array containing values
	   from	the sample item, and blesses it	into that class.

       o   If called on	an array-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 method-value pairs, calls each named method
	   with	the associated value as	an argument.

       o   Returns the new instance.

       Sample declaration and usage:

	 package MyObject;
	 use Class::MakeMethods::Standard::Array (
	   new => 'new',
	 );
	 ...

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

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

	 # Copy	with overriding	sequence of method calls
	 my $copy = $obj->new( bar => 'Bob' );

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

       o   Must	be called on an	array-based instance.

       o   Determines the array	position associated with the method name, and
	   uses	that as	an index into each instance to access the related
	   value. This defaults	to the next available slot in %FIELDS, but you
	   may override	this with the "'array_index' ="	number>	method
	   parameter, or by pre-filling	the contents of	%FIELDS.

       o   If called without any arguments returns the current value (or
	   undef).

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

       Sample declaration and usage:

	 package MyObject;
	 use Class::MakeMethods::Standard::Array (
	   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 an	array-based instance.

       o   Determines the array	position associated with the method name, and
	   uses	that as	an index into each instance to access the related
	   value. This defaults	to the next available slot in %FIELDS, but you
	   may override	this with the "'array_index' ="	number>	method
	   parameter, or by pre-filling	the contents of	%FIELDS.

       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::Standard::Array (
	   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 an	array-based instance.

       o   Determines the array	position associated with the method name, and
	   uses	that as	an index into each instance to access the related
	   value. This defaults	to the next available slot in %FIELDS, but you
	   may override	this with the "'array_index' ="	number>	method
	   parameter, or by pre-filling	the contents of	%FIELDS.

       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 argument,	uses that argument as an index to
	   retrieve from the referenced	hash, and returns that value (or
	   undef). If the single argument is an	array ref, then	a slice	of the
	   referenced hash is returned.

       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::Standard::Array (
	   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 an	array-based instance.

       o   Determines the array	position associated with the method name, and
	   uses	that as	an index into each instance to access the related
	   value. This defaults	to the next available slot in %FIELDS, but you
	   may override	this with the "'array_index' ="	number>	method
	   parameter, or by pre-filling	the contents of	%FIELDS.

       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::Standard::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::Standard	for more about this family of
       subclasses.

       See Class::MakeMethods::Standard::Hash for equivalent functionality
       based on	blessed	hashes.	If your	module will be extensively subclassed,
       consider	switching to Standard::Hash to avoid the subclassing concerns
       described above.

perl v5.24.1			  2004-09-06   MakeMethods::Standard::Array(3)

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

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=Class::MakeMethods::Standard::Array&sektion=3&manpath=FreeBSD+12.0-RELEASE+and+Ports>

home | help