NAME¶
Class::MakeMethods::Basic::Array - Basic array methods
SYNOPSIS¶
package MyObject;
use Class::MakeMethods::Basic::Array (
new => 'new',
scalar => [ 'foo', 'bar' ],
array => 'my_list',
hash => 'my_index',
);
...
# Constructor
my $obj = MyObject->new( foo => 'Foozle' );
# Scalar Accessor
print $obj->foo();
$obj->bar('Barbados');
print $obj->bar();
# Array accessor
$obj->my_list(0 => 'Foozle', 1 => 'Bang!');
print $obj->my_list(1);
# Hash accessor
$obj->my_index('broccoli' => 'Blah!', 'foo' => 'Fiddle');
print $obj->my_index('foo');
DESCRIPTION¶
The Basic::Array subclass 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::Basic for a summary,
or "USAGE" in Class::MakeMethods for full details.
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::Basic for more syntax
information.
About Positional Accessors¶
Each accessor method claims the next available spot in the array to store its
value in.
The mapping between method names and array positions is stored in a hash named
%FIELDS in the target package. When the first positional accessor is defined
for a package, its %FIELDS are initialized by searching its inheritance tree.
Caution: 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:
- •
- If you inherit from more than one class with positional accessors, the
positions used by the two sets of methods will overlap.
- •
- 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:
- •
- If called as a class method, makes a new array 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::Basic::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:
- •
- Must be called on an array-based instance.
- •
- Determines the array position associated with the method name, and uses
that as an index into each instance to access the related value.
- •
- 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::Basic::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:
- •
- Must be called on an array-based instance.
- •
- Determines the array position associated with the method name, and uses
that as an index into each instance to access the related value.
- •
- 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 one argument, uses that argument as an index to retrieve
from the referenced array, and returns that value (or undef). If the
single argument is an array ref, then a slice of the referenced array is
returned.
- •
- If called with a list of index-value pairs, 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.
Sample declaration and usage:
package MyObject;
use Class::MakeMethods::Basic::Array (
array => 'bar',
);
...
# 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);
# Retrieve slice of values by position
print join(', ', $obj->bar( [0, 2] ) );
# Direct access to referenced array
print scalar @{ $obj->bar() };
# Reset the array contents to empty
@{ $obj->bar() } = ();
hash - Instance Ref Accessor¶
For each method name passed, uses a closure to generate a subroutine with the
following characteristics:
- •
- Must be called on an array-based instance.
- •
- Determines the array position associated with the method name, and uses
that as an index into each instance to access the related value.
- •
- The value for each instance will be a reference to a hash (or undef).
- •
- If called without any arguments, returns the current hash-ref value (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 current hash-ref value.
Sample declaration and usage:
package MyObject;
use Class::MakeMethods::Basic::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');
# Retrieve 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() } = ();
SEE ALSO¶
See Class::MakeMethods for general information about this distribution.
See Class::MakeMethods::Basic for more about this family of subclasses.