| Class::MakeMethods::Standard::Array - Methods for Array objects |
Class::MakeMethods::Standard::Array - Methods for Array objects
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');
The Standard::Array suclass of MakeMethods provides a basic constructor and accessors for blessed-array object instances.
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 the Class::MakeMethods::Standard manpage for more information.
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 the Class::MakeMethods::Standard manpage and Parameter Syntax in the Class::MakeMethods::Standard manpage for more information.
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:
For each method name passed, returns a subroutine with the following characteristics:
'defaults' = array_ref> method parameter.
If called as a class method, makes a new array containing values from the sample item, and blesses it into that class.
If called on an array-based instance, makes a copy of it and blesses the copy into the same class as the original instance.
If passed a list of method-value pairs, calls each named method with the associated value as an argument.
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' );
For each method name passed, uses a closure to generate a subroutine with the following characteristics:
'array_index' = number> method parameter, or by pre-filling the contents of %FIELDS.
If called without any arguments returns the current value (or undef).
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;
For each method name passed, uses a closure to generate a subroutine with the following characteristics:
'array_index' = number> method parameter, or by pre-filling the contents of %FIELDS.
The value for each instance will be a reference to an array (or undef).
If called without any arguments, returns the current array-ref value (or undef).
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).
If called with a single array ref argument, uses that list to return a slice of the referenced array.
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.
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' );
For each method name passed, uses a closure to generate a subroutine with the following characteristics:
'array_index' = number> method parameter, or by pre-filling the contents of %FIELDS.
The value for each instance will be a reference to a hash (or undef).
If called without any arguments, returns the contents of the hash in list context, or a hash reference in scalar context (or undef).
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.
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() } = ();
For each method name passed, uses a closure to generate a subroutine with the following characteristics:
'array_index' = number> method parameter, or by pre-filling the contents of %FIELDS.
The value for each instance will be a reference to an object (or undef).
If called without any arguments returns the current value.
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 the Class::MakeMethods manpage for general information about this distribution.
See the Class::MakeMethods::Standard manpage for more about this family of subclasses.
See the Class::MakeMethods::Standard::Hash manpage 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.
| Class::MakeMethods::Standard::Array - Methods for Array objects |