MakeMethods::Basic::HaUser)Contributed Perl DocumenMakeMethods::Basic::Hash(3)NAMEClass::MakeMethods::Basic::Hash - Basic hash methods
SYNOPSIS
package MyObject;
use Class::MakeMethods::Basic::Hash (
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::Hash subclass of MakeMethods provides a basic constructor
and accessors for blessed-hash 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.
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 hash and blesses it into
that class.
· If called on a hash-based instance, makes a copy of it and blesses
the copy into the same class as the original instance.
· 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.
· Returns the new instance.
Sample declaration and usage:
package MyObject;
use Class::MakeMethods::Basic::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' );
scalar - Instance Accessor
For each method name passed, uses a closure to generate a subroutine
with the following characteristics:
· Must be called on a hash-based instance.
· Uses the method name as a hash key to access the related value for
each instance.
· 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::Basic::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:
· Must be called on a hash-based instance.
· Uses the method name as a hash key to access the related value for
each instance.
· 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 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::Hash (
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);
# 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 a hash-based instance.
· Uses the method name as a hash key to access the related value for
each instance.
· 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 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::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');
# 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.
See Class::MakeMethods::Basic::Array for equivalent functionality based
on blessed arrays. If all access to your object is through constructors
and accessors declared using this package, and your class will not be
extensively subclassed, consider switching to Basic::Array to minimize
resource consumption.
perl v5.14.2 2004-09-06 MakeMethods::Basic::Hash(3)