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  $automobile = Automobile->new;
  $van = Van->new;
  $automobile->compute_mileage; # Automobile!
  $van->compute_mileage;        # Automobile!, should also print Van!

C<Van!> will never be printed. This happens because B<Aspect> installs
advice code on symbol table entries. C<Van::compute_mileage> does not
have one, so nothing happens. Until this is solved, you have to do the
thinking about inheritance yourself.

=head2 Performance

You may find it very easy to shoot yourself in the foot with this module.
Consider this advice:

  # Do not do this!
  before {
      print $_->sub_name;
  } cflow 'MyApp::Company::make_report';

The advice code will be installed on B<every> sub loaded. The advice code
will only run when in the specified call flow, which is the correct
behavior, but it will be I<installed> on every sub in the system. This
can be extremely slow because the run-time cost of checking C<cflow> will
occur on every single function called in your program.

It happens because the C<cflow> pointcut matches I<all> subs during weave-time.
It matches the correct sub during run-time. The solution is to narrow the
pointcut:

  # Much better
  before {
      print $_->sub_name;
  } call qr/^MyApp::/
  & cflow 'MyApp::Company::make_report';

=head1 TO DO

There are a many things that could be added, if people have an interest
in contributing to the project.

=head2 Documentation

* cookbook

* tutorial

* example of refactoring a useful CPAN module using aspects

=head2 Pointcuts

* New pointcuts: execution, cflowbelow, within, advice, calledby. Sure
  you can implement them today with Perl treachery, but it is too much
  work.

* We need a way to match subs with an attribute, attributes::get()
  will currently not work.

* isa() support for method pointcuts as Gaal Yahas suggested: match
  methods on class hierarchies without callbacks

* Perl join points: phasic- BEGIN/INIT/CHECK/END 

=head2 Weaving

* The current optimation has gone as far as it can, next we need to look into
  XS acceleration and byte code manipulation with B:: modules.

* A debug flag to print out subs that were matched during weaving

* Warnings when over 1000 methods wrapped

* Allow finer control of advice execution order

* Centralised hooking in wrappers so that each successive advice won't need
  to wrap around the previous one.

* Allow lexical aspects to be safely removed completely, rather than being left
  in place and disabled as in the current implementation.

=head1 SUPPORT

Please report any bugs or feature requests through the web interface at
L<http://rt.cpan.org/Public/Dist/Display.html?Name=Aspect>.

=head1 INSTALLATION

See L<perlmodinstall> for information and options on installing Perl modules.

=head1 AVAILABILITY

The latest version of this module is available from the Comprehensive Perl
Archive Network (CPAN). Visit <http://www.perl.com/CPAN/> to find a CPAN
site near you. Or see L<http://search.cpan.org/perldoc?Aspect>.

=head1 AUTHORS

Adam Kennedy E<lt>adamk@cpan.orgE<gt>

Marcel GrE<uuml>nauer E<lt>marcel@cpan.orgE<gt>

Ran Eilam E<lt>eilara@cpan.orgE<gt>

=head1 SEE ALSO

You can find AOP examples in the C<examples/> directory of the
distribution.

L<Aspect::Library::Memoize>

L<Aspect::Library::Profiler>

L<Aspect::Library::Trace>

=head1 COPYRIGHT

Copyright 2001 by Marcel GrE<uuml>nauer

Some parts copyright 2009 - 2013 Adam Kennedy.