NAME

Aspect::Modular - Base class for modular aspects

SYNOPSIS

use base 'Aspect::Modular';
use Aspect qw(advice calls returns);

sub define {
  my ($self, $spec) = @_;
  $self->handlers_push(
    advice(calls($spec),   sub { ... }),
    advice(returns($spec), sub { ... })
  );
  $self->enable;
}

DESCRIPTION

This is the base class for modular aspects. Specific modular aspects need to override the define() method at least.

METHODS

This class implements the following methods:

new([args])

This is the constructor. It creates the object, then calls init() to handle any arguments that were passed to the constructor.

init([args])

This method initializes newly constructed objects. Since a modular aspect most likely, when instantiated, wants to create and enable some advice, it calls the define() method with the same arguments as init() got itself.

define(spec)

This method should be overridden in subclasses and create and enable the advice necessary to implement the modular aspect. All advice should be pushed onto the object's handler array using handler_push(). See subclasses for examples.

enable([packages])

disable([packages])

handlers()

Each aspect object stores lexical handlers created by installing advice code on join points in an array called handlers. For example, call and return join points install advice by wrapping the affected subroutine using Hook::LexWrap. Those wrappers are lexically bound, so if we want to disable them and restore the subroutine to its original state, all we need to do is to let the handlers go out of scope. See the Hook::LexWrap manpage for details. Obviously, if the modular aspect goes out of scope, so do the handlers.

Access to these handlers is defined via a list property created by Class::MethodMaker.

This accessor returns the handlers. In an array context it returns them as an array and in scalar context as a reference to the array.

handlers_push(advice)

Pushes a list of handlers onto the handlers array. Cf. push() in perlfunc.

handlers_pop()

Pops an entry off the handlers array and returns it. Cf. pop() in perlfunc.

handlers_shift(advice)

Shifts a list of handlers onto the handlers array. Cf. shift() in perlfunc.

handlers_unshift()

Unshifts an entry off the handlers array and returns it. Cf. unshift() in perlfunc.

handlers_splice()

Splices the handlers array. Cf. splice() in perlfunc.

handlers_clear()

Clears the handlers array.

handlers_count()

Returns the number of elements in x.

handlers_index(indices)

Takes a list of indices, returns a list of the corresponding values.

handlers_set(list)

Takes a list, treated as pairs of index => value; each given index is set to the corresponding value. No return value.

BUGS

None known so far. If you find any bugs or oddities, please do inform the author.

AUTHOR

Marcel Grünauer <marcel@cpan.org>

COPYRIGHT

Copyright 2001-2002 Marcel Grünauer. All rights reserved.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

perl(1), Aspect::Intro(3pm), Aspect::Overview(3pm).