NAME¶
Class::MakeMethods::Evaled::Hash - Typical hash methods
SYNOPSIS¶
package MyObject;
use Class::MakeMethods::Evaled::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 Evaled::Hash subclass of MakeMethods provides a simple 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::Standard 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::Standard 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::Evaled::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::Evaled::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::Evaled::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::Evaled::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::Evaled for more about this family of subclasses.