package Role::Tiny;
-use strictures 1;
-use Class::Tiny::_Utils;
+sub _getglob { \*{$_[0]} }
+sub _getstash { \%{"$_[0]::"} }
+
+use strict;
+use warnings FATAL => 'all';
+
+our $VERSION = '1.000000'; # 1.0.0
+$VERSION = eval $VERSION;
our %INFO;
our %APPLIED_TO;
+our %COMPOSED;
+
+# Module state workaround totally stolen from Zefram's Module::Runtime.
+
+BEGIN {
+ *_WORK_AROUND_BROKEN_MODULE_STATE = "$]" < 5.009 ? sub(){1} : sub(){0};
+}
+
+sub Role::Tiny::__GUARD__::DESTROY {
+ delete $INC{$_[0]->[0]} if @{$_[0]};
+}
+
+sub _load_module {
+ (my $proto = $_[0]) =~ s/::/\//g;
+ $proto .= '.pm';
+ return 1 if $INC{$proto};
+ # can't just ->can('can') because a sub-package Foo::Bar::Baz
+ # creates a 'Baz::' key in Foo::Bar's symbol table
+ return 1 if grep !/::$/, keys %{_getstash($_[0])||{}};
+ my $guard = _WORK_AROUND_BROKEN_MODULE_STATE
+ && bless([ $proto ], 'Role::Tiny::__GUARD__');
+ require $proto;
+ pop @$guard if _WORK_AROUND_BROKEN_MODULE_STATE;
+ return 1;
+}
sub import {
my $target = caller;
- strictures->import;
+ my $me = shift;
+ strict->import;
+ warnings->import(FATAL => 'all');
+ return if $INFO{$target}; # already exported into this package
# get symbol table reference
my $stash = do { no strict 'refs'; \%{"${target}::"} };
# install before/after/around subs
foreach my $type (qw(before after around)) {
*{_getglob "${target}::${type}"} = sub {
+ require Class::Method::Modifiers;
push @{$INFO{$target}{modifiers}||=[]}, [ $type => @_ ];
};
}
};
*{_getglob "${target}::with"} = sub {
die "Only one role supported at a time by with" if @_ > 1;
- Role::Tiny->apply_role_to_package($_[0], $target);
+ $me->apply_role_to_package($target, $_[0]);
};
- *{_getglob "${target}::has"} = sub {
- my ($name, %spec) = @_;
- ($INFO{$target}{accessor_maker} ||= do {
- require Method::Generate::Accessor;
- Method::Generate::Accessor->new
- })->generate_method($target, $name, \%spec);
- $INFO{$target}{attributes}{$name} = \%spec;
- };
- # grab all *non-constant* (ref eq 'SCALAR') subs present
+ # grab all *non-constant* (stash slot is not a scalarref) subs present
# in the symbol table and store their refaddrs (no need to forcibly
# inflate constant subs into real subs) - also add '' to here (this
# is used later)
@{$INFO{$target}{not_methods}={}}{
- '', map { *$_{CODE}||() } grep !(ref eq 'SCALAR'), values %$stash
+ '', map { *$_{CODE}||() } grep !ref($_), values %$stash
} = ();
# a role does itself
$APPLIED_TO{$target} = { $target => undef };
}
sub apply_role_to_package {
- my ($class, $role, $to) = @_;
+ my ($me, $to, $role) = @_;
+
+ _load_module($role);
+
die "This is apply_role_to_package" if ref($to);
- die "Not a Role::Tiny" unless my $info = $INFO{$role};
- my $methods = $info->{methods} ||= do {
+ die "${role} is not a Role::Tiny" unless my $info = $INFO{$role};
+
+ $me->_check_requires($to, $role, @{$info->{requires}||[]});
+
+ $me->_install_methods($to, $role);
+
+ $me->_install_modifiers($to, $info->{modifiers});
+
+ # only add does() method to classes and only if they don't have one
+ if (not $INFO{$to} and not $to->can('does')) {
+ *{_getglob "${to}::does"} = \&does_role;
+ }
+
+ # copy our role list into the target's
+ @{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = ();
+}
+
+sub apply_roles_to_object {
+ my ($me, $object, @roles) = @_;
+ die "No roles supplied!" unless @roles;
+ my $class = ref($object);
+ bless($object, $me->create_class_with_roles($class, @roles));
+ $object;
+}
+
+sub create_class_with_roles {
+ my ($me, $superclass, @roles) = @_;
+
+ die "No roles supplied!" unless @roles;
+
+ my $new_name = join(
+ '__WITH__', $superclass, my $compose_name = join '__AND__', @roles
+ );
+
+ return $new_name if $COMPOSED{class}{$new_name};
+
+ foreach my $role (@roles) {
+ _load_module($role);
+ die "${role} is not a Role::Tiny" unless $INFO{$role};
+ }
+
+ if ($] >= 5.010) {
+ require mro;
+ } else {
+ require MRO::Compat;
+ }
+
+ my @composable = map $me->_composable_package_for($_), reverse @roles;
+
+ *{_getglob("${new_name}::ISA")} = [ @composable, $superclass ];
+
+ my @info = map $INFO{$_}, @roles;
+
+ $me->_check_requires(
+ $new_name, $compose_name,
+ do { my %h; @h{map @{$_->{requires}||[]}, @info} = (); keys %h }
+ );
+
+ *{_getglob "${new_name}::does"} = \&does_role unless $new_name->can('does');
+
+ @{$APPLIED_TO{$new_name}||={}}{
+ map keys %{$APPLIED_TO{$_}}, @roles
+ } = ();
+
+ $COMPOSED{class}{$new_name} = 1;
+ return $new_name;
+}
+
+sub _composable_package_for {
+ my ($me, $role) = @_;
+ my $composed_name = 'Role::Tiny::_COMPOSABLE::'.$role;
+ return $composed_name if $COMPOSED{role}{$composed_name};
+ $me->_install_methods($composed_name, $role);
+ my $base_name = $composed_name.'::_BASE';
+ *{_getglob("${composed_name}::ISA")} = [ $base_name ];
+ my $modifiers = $INFO{$role}{modifiers}||[];
+ my @mod_base;
+ foreach my $modified (
+ do { my %h; @h{map $_->[1], @$modifiers} = (); keys %h }
+ ) {
+ push @mod_base, "sub ${modified} { shift->next::method(\@_) }";
+ }
+ my $e;
+ {
+ local $@;
+ eval(my $code = join "\n", "package ${base_name};", @mod_base);
+ $e = "Evaling failed: $@\nTrying to eval:\n${code}" if $@;
+ }
+ die $e if $e;
+ $me->_install_modifiers($composed_name, $modifiers);
+ $COMPOSED{role}{$composed_name} = 1;
+ return $composed_name;
+}
+
+sub _check_requires {
+ my ($me, $to, $name, @requires) = @_;
+ if (my @requires_fail = grep !$to->can($_), @requires) {
+ # role -> role, add to requires, role -> class, error out
+ if (my $to_info = $INFO{$to}) {
+ push @{$to_info->{requires}||=[]}, @requires_fail;
+ } else {
+ die "Can't apply ${name} to ${to} - missing ".join(', ', @requires_fail);
+ }
+ }
+}
+
+sub _concrete_methods_of {
+ my ($me, $role) = @_;
+ my $info = $INFO{$role};
+ $info->{methods} ||= do {
# grab role symbol table
my $stash = do { no strict 'refs'; \%{"${role}::"}};
my $not_methods = $info->{not_methods};
my $code = *{$stash->{$_}}{CODE};
# rely on the '' key we added in import for "no code here"
exists $not_methods->{$code||''} ? () : ($_ => $code)
- } grep !(ref($stash->{$_}) eq 'SCALAR'), keys %$stash
+ } grep !ref($stash->{$_}), keys %$stash
};
};
+}
+
+sub methods_provided_by {
+ my ($me, $role) = @_;
+ die "${role} is not a Role::Tiny" unless my $info = $INFO{$role};
+ (keys %{$me->_concrete_methods_of($role)}, @{$info->{requires}||[]});
+}
+
+sub _install_methods {
+ my ($me, $to, $role) = @_;
+
+ my $info = $INFO{$role};
+
+ my $methods = $me->_concrete_methods_of($role);
+
# grab target symbol table
my $stash = do { no strict 'refs'; \%{"${to}::"}};
+
# determine already extant methods of target
my %has_methods;
@has_methods{grep
- +((ref($stash->{$_}) eq 'SCALAR') || (*{$stash->{$_}}{CODE})),
+ +(ref($stash->{$_}) || *{$stash->{$_}}{CODE}),
keys %$stash
} = ();
- if (my @requires_fail
- = grep !exists $has_methods{$_}, @{$info->{requires}||[]}) {
- # role -> role, add to requires, role -> class, error out
- if (my $to_info = $INFO{$to}) {
- push @{$to_info->{requires}||=[]}, @requires_fail;
- } else {
- die "Can't apply ${role} to ${to} - missing ".join(', ', @requires_fail);
- }
- }
- my @to_install = grep !exists $has_methods{$_}, keys %$methods;
- foreach my $i (@to_install) {
+ foreach my $i (grep !exists $has_methods{$_}, keys %$methods) {
no warnings 'once';
*{_getglob "${to}::${i}"} = $methods->{$i};
}
+}
- foreach my $modifier (@{$info->{modifiers}||[]}) {
- _install_modifier($to, @{$modifier});
- }
-
- # only add does() method to classes and only if they don't have one
- if (not $INFO{$to} and not $to->can('does')) {
- ${_getglob "${to}::does"} = \&does_role;
- }
-
- if (my $attr_info = $info->{attributes}) {
- if ($INFO{$to}) {
- @{$INFO{$to}{attributes}||={}}{keys %$attr_info} = values %$attr_info;
- } else {
- my $con = $Class::Tiny::MAKERS{$to}{constructor} ||= do {
- require Method::Generate::Constructor;
- Method::Generate::Constructor
- ->new(package => $to)
- ->install_delayed
- ->register_attribute_specs(do {
- my @spec;
- if (my $super = do { no strict 'refs'; ${"${to}::ISA"}[0] }) {
- if (my $con = $Class::Tiny::MAKERS{$super}{constructor}) {
- @spec = %{$con->all_attribute_specs};
- }
- }
- @spec;
- });
- };
- $con->register_attribute_specs(%$attr_info);
+sub _install_modifiers {
+ my ($me, $to, $modifiers) = @_;
+ if (my $info = $INFO{$to}) {
+ push @{$info->{modifiers}}, @{$modifiers||[]};
+ } else {
+ foreach my $modifier (@{$modifiers||[]}) {
+ $me->_install_single_modifier($to, @$modifier);
}
}
+}
- # copy our role list into the target's
- @{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = ();
+sub _install_single_modifier {
+ my ($me, @args) = @_;
+ Class::Method::Modifiers::install_modifier(@args);
}
sub does_role {
- my ($package, $role) = @_;
- return exists $APPLIED_TO{$package}{$role};
+ my ($proto, $role) = @_;
+ return exists $APPLIED_TO{ref($proto)||$proto}{$role};
}
1;
+
+=head1 NAME
+
+Role::Tiny - Roles. Like a nouvelle cuisine portion size slice of Moose.
+
+=head1 SYNOPSIS
+
+ package Some::Role;
+
+ use Role::Tiny;
+
+ sub foo { ... }
+
+ sub bar { ... }
+
+ around baz => sub { ... }
+
+ 1;
+
+else where
+
+ package Some::Class;
+
+ use Role::Tiny::With;
+
+ # bar gets imported, but not foo
+ with 'Some::Role';
+
+ sub foo { ... }
+
+ # baz is wrapped in the around modifier by Class::Method::Modifiers
+ sub baz { ... }
+
+ 1;
+
+If you wanted attributes as well, look at L<Moo::Role>.
+
+=head1 DESCRIPTION
+
+C<Role::Tiny> is a minimalist role composition tool.
+
+=head1 ROLE COMPOSITION
+
+Role composition can be thought of as much more clever and meaningful multiple
+inheritance. The basics of this implementation of roles is:
+
+=over 2
+
+=item *
+
+If a method is already defined on a class, that method will not be composed in
+from the role.
+
+=item *
+
+If a method that the role L</requires> to be implemented is not implemented,
+role application will fail loudly.
+
+=back
+
+Unlike L<Class::C3>, where the B<last> class inherited from "wins," role
+composition is the other way around, where first wins. In a more complete
+system (see L<Moose>) roles are checked to see if they clash. The goal of this
+is to be much simpler, hence disallowing composition of multiple roles at once.
+
+=head1 METHODS
+
+=head2 apply_role_to_package
+
+ Role::Tiny->apply_role_to_package('Some::Package', 'Some::Role');
+
+Composes role with package. See also L<Role::Tiny::With>.
+
+=head2 apply_roles_to_object
+
+ Role::Tiny->apply_roles_to_object($foo, qw(Some::Role1 Some::Role2));
+
+Composes roles in order into object directly. Object is reblessed into the
+resulting class.
+
+=head2 create_class_with_roles
+
+ Role::Tiny->create_class_with_roles('Some::Base', qw(Some::Role1 Some::Role2));
+
+Creates a new class based on base, with the roles composed into it in order.
+New class is returned.
+
+=head1 SUBROUTINES
+
+=head2 does_role
+
+ if (Role::Tiny::does_role($foo, 'Some::Role')) {
+ ...
+ }
+
+Returns true if class has been composed with role.
+
+This subroutine is also installed as ->does on any class a Role::Tiny is
+composed into unless that class already has an ->does method, so
+
+ if ($foo->does('Some::Role')) {
+ ...
+ }
+
+will work for classes but to test a role, one must use ::does_role directly
+
+=head1 IMPORTED SUBROUTINES
+
+=head2 requires
+
+ requires qw(foo bar);
+
+Declares a list of methods that must be defined to compose role.
+
+=head2 with
+
+ with 'Some::Role1';
+ with 'Some::Role2';
+
+Composes another role into the current role. Only one role may be composed in
+at a time to allow the code to remain as simple as possible.
+
+=head2 before
+
+ before foo => sub { ... };
+
+See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full
+documentation.
+
+Note that since you are not required to use method modifiers,
+L<Class::Method::Modifiers> is lazily loaded and we do not declare it as
+a dependency. If your L<Role::Tiny> role uses modifiers you must depend on
+both L<Class::Method::Modifiers> and L<Role::Tiny>.
+
+=head2 around
+
+ around foo => sub { ... };
+
+See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full
+documentation.
+
+Note that since you are not required to use method modifiers,
+L<Class::Method::Modifiers> is lazily loaded and we do not declare it as
+a dependency. If your L<Role::Tiny> role uses modifiers you must depend on
+both L<Class::Method::Modifiers> and L<Role::Tiny>.
+
+=head2 after
+
+ after foo => sub { ... };
+
+See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full
+documentation.
+
+Note that since you are not required to use method modifiers,
+L<Class::Method::Modifiers> is lazily loaded and we do not declare it as
+a dependency. If your L<Role::Tiny> role uses modifiers you must depend on
+both L<Class::Method::Modifiers> and L<Role::Tiny>.
+
+=head1 SEE ALSO
+
+L<Role::Tiny> is the attribute-less subset of L<Moo::Role>; L<Moo::Role> is
+a meta-protocol-less subset of the king of role systems, L<Moose::Role>.
+
+If you don't want method modifiers and do want to be forcibly restricted
+to a single role application per class, Ovid's L<Role::Basic> exists. But
+Stevan Little (the L<Moose> author) and I are both still convinced that
+he's Doing It Wrong.
+
+=head1 AUTHOR
+
+mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>
+
+=head1 CONTRIBUTORS
+
+dg - David Leadbeater (cpan:DGL) <dgl@dgl.cx>
+
+frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <frioux@gmail.com>
+
+hobbs - Andrew Rodland (cpan:ARODLAND) <arodland@cpan.org>
+
+jnap - John Napiorkowski (cpan:JJNAPIORK) <jjn1056@yahoo.com>
+
+ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <ribasushi@cpan.org>
+
+chip - Chip Salzenberg (cpan:CHIPS) <chip@pobox.com>
+
+ajgb - Alex J. G. Burzyński (cpan:AJGB) <ajgb@cpan.org>
+
+doy - Jesse Luehrs (cpan:DOY) <doy at tozt dot net>
+
+perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org>
+
+=head1 COPYRIGHT
+
+Copyright (c) 2010-2012 the Role::Tiny L</AUTHOR> and L</CONTRIBUTORS>
+as listed above.
+
+=head1 LICENSE
+
+This library is free software and may be distributed under the same terms
+as perl itself.
+
+=cut
projects / gitmo/Role-Tiny.git / blobdiff