=pod

=encoding utf-8

=for stopwords invocant invocants lexicals unintuitive yada globals

=head1 NAME

Kavorka::Manual::MethodModifiers - before/after/around keywords

=head1 DESCRIPTION

Kavorka provides the C<before>, C<after> and C<around> keywords for
method modifiers.

Method modifiers should work in L<Moose>, L<Moo>, L<Mouse> and
L<Role::Tiny> classes and roles. In other classes they will fall back
to using L<Class::Method::Modifiers>.

The keywords C<augment> and C<override> are also available, but will
only work in classes backed by a framework that supports these
modifiers (i.e. L<Moose> or L<Mouse>, but I<not> L<Moo>).

The anatomy of a method modifier:

=over

=item 1.

The keyword introducing the method.

=item 2.

The method names.

=item 3.

The signature (optional).

=item 4.

Traits (optional).

=item 5.

The prototype (optional).

=item 6.

The attribute list (optional).

=item 7.

The modifier body.

=back

Example:

   #  (1)   (2)    (3)    (4)     (5)  (6)     (7)
      after foobar ($foo) is cool :($) :cached { $self->log("foobar $foo") }

=head2 The Keyword

By default, these keywords are exported. They must be exported by
request:

   use Kavorka qw( before after around );
   use Kavorka qw( -modifiers );

=head2 The Method Names

These are the names of the methods being wrapped. 

Multiple names may be separated by colons:

   after foo, bar, baz { ... }

=head2 The Signature

See L<Kavorka::Manual::Signatures>.

The C<before> and C<after> keywords have a default invocant called
C<< $self >>, but it does not have a type constraint, so can equally
be used for class or object methods.

The C<around> modifier defines two invocants called C<< $next >> and
C<< $self >>. (C<< ${^NEXT} >> is also available as an alias for
C<< $next >> for backwards compatibility with Moops::MethodModifiers.)

Beware using type constraints for method modifiers (which are
essentially wrappers); constraints will be checked at each level of
wrapping which will slow down method calls.

=head2 Traits

See L<Kavorka::Manual::ExtendingKavorka>.

=head2 The Prototype

See L<Kavorka::Manual::PrototypeAndAttributes>.

Note however that prototypes are fairly useless for methods.

=head2 The Attributes

Attributes may alternatively be provided I<< before the signature >>.

See L<Kavorka::Manual::PrototypeAndAttributes>.

Note that this applies the attribute to the modifier code, and not to
the method being modified.

=head2 The Modifier Body

This is more or less what you'd expect from the modifier body you'd
write with L<Moose>, however the lexical variables for parameters
are pre-declared and pre-populated, and invocants have been shifted
off C<< @_ >>.

=head1 BUGS

Please report any bugs to
L<http://rt.cpan.org/Dist/Display.html?Queue=Kavorka>.

=head1 SEE ALSO

L<Kavorka::Manual>,
L<Kavorka::Manual::Signatures>,
L<Kavorka::Manual::PrototypeAndAttributes>,
L<Kavorka::Manual::Methods>.

=head1 AUTHOR

Toby Inkster E<lt>tobyink@cpan.orgE<gt>.

=head1 COPYRIGHT AND LICENCE

This software is copyright (c) 2013-2014, 2017 by Toby Inkster.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=head1 DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

