MakeMethods::Basic::ArUser3Contributed Perl DocumeMakeMethods::Basic::Array(3)NAMEClass::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.
perl v5.14.2 2004-09-06 MakeMethods::Basic::Array(3)