Class::MakeMethods::Template::Universal - Meta-methods for any type of object
package MyObject; use Class::MakeMethods::Template::Universal ( 'no_op' => [ 'twiddle' ], 'croak' => [ 'fail', { croak_msg => 'Curses!' } ] ); package main; MyObject->twiddle; # Does nothing if ( $foiled ) { MyObject->fail() } # Dies with croak_msg
The following meta-methods and behaviors are applicable across multiple types of classes and objects.
You can use any of these features in your meta-method interfaces without explicitly importing them.
Modifiers
-private
Causes the method to croak if it is called from outside of the package which originally declared it.
Note that this protection can currently be circumvented if your class provides the method_init behavior, or another subroutine that calls methods by name.
-protected
Causes the method to croak if it is called from a package other than the declaring package and its inheritors.
-public
Cancels any previous -private or -protected declaration.
-self_closure
Causes the method to return a function reference which is bound to the arguments provided when it is first called.
For examples of usage, see the test scripts in t/*self_closure*.t.
-warn_calls
For diagnostic purposes, call warn with the object reference, method name, and arguments before executing the body of the method.
Behaviors
attributes
Runtime access to method parameters.
no_op.
croak.
method_init.
For each meta-method, creates a method with an empty body.
no_op => [ qw / foo bar baz / ]
You might want to create and use such methods to provide hooks for subclass activity.
No interfaces or parameters supported.
For each meta-method, creates a method which will croak if called.
croak => [ qw / foo bar baz / ]
This is intended to support the use of abstract methods, that must be overidden in a useful subclass.
If each subclass is expected to provide an implementation of a given method, using this abstract method will replace the generic error message below with the clearer, more explicit error message that follows it:
Can't locate object method "foo" via package "My::Subclass" The "foo" method is abstract and can not be called on My::Subclass
However, note that the existence of this method will be detected by UNIVERSAL::can(), so it is not suitable for use in optional interfaces, for which you may wish to be able to detect whether the method is supported or not.
The -unsupported and -prohibited interfaces provide alternate error messages, or a custom error message can be provided using the 'croak_msg' parameter.
Creates a method that accepts a hash of key-value pairs, or a reference to hash of such pairs. For each pair, the key is interpreted as the name of a method to call, and the value is the argument to be passed to that method.
Example: After declaring the below method_init method, $self-init( foo=>123, bar=>456 );> is equivalent to $self-foo(123); $self->bar(456);>.
$self-
Class::MakeMethods->make( 'method_init' => [ 'init' ] );
Creates a method which delegates to an object provided by another method.
Example:
use Class::MakeMethods::Template::Universal forward_methods => [ --target=> 'whistle', w, [ 'x', 'y' ], { target=> 'xylophone' }, { name=>'z', target=>'zither', target_args=>[123], method_name=>do_zed }, ];
Example: The above defines that method w will be handled by the calling w on the object returned by whistle, whilst methods x and y will be handled by xylophone, and method z will be handled by calling do_zed on the object returned by calling zither(123).
w
whistle
x
y
xylophone
z
do_zed
zither(123)
Parameters: The following additional parameters are supported:
Required. The name of the method that will provide the object that will handle the operation.
Optional ref to an array of arguments to be passed to the target method.
The name of the method to call on the handling object. Defaults to the name of the meta-method being created.
To install Class::MakeMethods, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Class::MakeMethods
CPAN shell
perl -MCPAN -e shell install Class::MakeMethods
For more information on module installation, please visit the detailed CPAN module installation guide.