Class::C3::Adopt::NEXTUser Contributed Perl DocumentaClass::C3::Adopt::NEXT(3)NAMEClass::C3::Adopt::NEXT - make NEXT suck less
SYNOPSIS
package MyApp::Plugin::FooBar;
#use NEXT;
use Class::C3::Adopt::NEXT;
# or 'use Class::C3::Adopt::NEXT -no_warn;' to suppress warnings
# Or use warnings::register
# no warnings 'Class::C3::Adopt::NEXT';
# Or suppress warnings in a set of modules from one place
# no Class::C3::Adopt::NEXT qw/ Module1 Module2 Module3 /;
# Or suppress using a regex
# no Class::C3::Adopt::NEXT qr/^Module\d$/;
sub a_method {
my ($self) = @_;
# Do some stuff
# Re-dispatch method
# Note that this will generate a warning the _first_ time the package
# uses NEXT unless you un comment the 'no warnings' line above.
$self->NEXT::method();
}
DESCRIPTION
NEXT was a good solution a few years ago, but isn't any more. It's
slow, and the order in which it re-dispatches methods appears random at
times. It also encourages bad programming practices, as you end up with
code to re-dispatch methods when all you really wanted to do was run
some code before or after a method fired.
However, if you have a large application, then weaning yourself off
"NEXT" isn't easy.
This module is intended as a drop-in replacement for NEXT, supporting
the same interface, but using Class::C3 to do the hard work. You can
then write new code without "NEXT", and migrate individual source files
to use "Class::C3" or method modifiers as appropriate, at whatever pace
you're comfortable with.
WARNINGS
This module will warn once for each package using NEXT. It uses
warnings::register, and so can be disabled like by adding "no warnings
'Class::C3::Adopt::NEXT';" to each package which generates a warning,
or adding "use Class::C3::Adopt::NEXT -no_warn;", or disable multiple
modules at once by saying:
no Class::C3::Adopt::NEXT qw/ Module1 Module2 Module3 /;
somewhere before the warnings are first triggered. You can also setup
entire name spaces of modules which will not warn using a regex, e.g.
no Class::C3::Adopt::NEXT qr/^Module\d$/;
MIGRATING
Current code using NEXT
You add "use MRO::Compat" to the top of a package as you start
converting it, and gradually replace your calls to "NEXT::method()"
with "maybe::next::method()", and calls to "NEXT::ACTUAL::method()"
with "next::method()".
Example:
sub yourmethod {
my $self = shift;
# $self->NEXT::yourmethod(@_); becomes
$self->maybe::next::method();
}
sub othermethod {
my $self = shift;
# $self->NEXT::ACTUAL::yourmethodname(); becomes
$self->next::method();
}
On systems with Class::C3::XS present, this will automatically be used
to speed up method re-dispatch. If you are running perl version 5.9.5
or greater then the C3 method resolution algorithm is included in perl.
Correct use of MRO::Compat as shown above allows your code to be
seamlessly forward and backwards compatible, taking advantage of native
versions if available, but falling back to using pure perl "Class::C3".
Writing new code
Use Moose and make all of your plugins Moose::Roles, then use method
modifiers to wrap methods.
Example:
package MyApp::Role::FooBar;
use Moose::Role;
before 'a_method' => sub {
my ($self) = @_;
# Do some stuff
};
around 'a_method' => sub {
my $orig = shift;
my $self = shift;
# Do some stuff before
my $ret = $self->$orig(@_); # Run wrapped method (or not!)
# Do some stuff after
return $ret;
};
package MyApp;
use Moose;
with 'MyApp::Role::FooBar';
CAVEATS
There are some inheritance hierarchies that it is possible to create
which cannot be resolved to a simple C3 hierarchy. In that case, this
module will fall back to using "NEXT". In this case a warning will be
emitted.
Because calculating the MRO of every class every time "->NEXT::foo" is
used from within it is too expensive, runtime manipulations of @ISA are
prohibited.
FUNCTIONS
This module replaces "NEXT::AUTOLOAD" with it's own version. If
warnings are enabled then a warning will be emitted on the first use of
"NEXT" by each package.
SEE ALSO
MRO::Compat and Class::C3 for method re-dispatch and Moose for method
modifiers and roles.
NEXT for documentation on the functionality you'll be removing.
AUTHORS
Florian Ragwitz <rafl@debian.org>
Tomas Doran <bobtfish@bobtfish.net>
COPYRIGHT AND LICENSE
This software is copyright (c) 2010 by Florian Ragwitz.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
perl v5.14.1 2010-05-07 Class::C3::Adopt::NEXT(3)
