3 sub _getglob { \*{$_[0]} }
4 sub _getstash { \%{"$_[0]::"} }
7 use warnings FATAL => 'all';
13 # inlined from Moo::_Utils - update that first.
16 (my $proto = $_[0]) =~ s/::/\//g;
17 return 1 if $INC{"${proto}.pm"};
18 # can't just ->can('can') because a sub-package Foo::Bar::Baz
19 # creates a 'Baz::' key in Foo::Bar's symbol table
20 return 1 if grep !/::$/, keys %{_getstash($_[0])||{}};
21 { local $@; require "${proto}.pm"; }
25 { # \[] is REF, not SCALAR. \v1 is VSTRING (thanks to doy for that one)
26 my %reftypes = map +($_ => 1), qw(SCALAR REF VSTRING);
27 sub _is_scalar_ref { $reftypes{ref($_[0])} }
34 return if $INFO{$target}; # already exported into this package
35 # get symbol table reference
36 my $stash = do { no strict 'refs'; \%{"${target}::"} };
37 # install before/after/around subs
38 foreach my $type (qw(before after around)) {
39 *{_getglob "${target}::${type}"} = sub {
40 { local $@; require Class::Method::Modifiers; }
41 push @{$INFO{$target}{modifiers}||=[]}, [ $type => @_ ];
44 *{_getglob "${target}::requires"} = sub {
45 push @{$INFO{$target}{requires}||=[]}, @_;
47 *{_getglob "${target}::with"} = sub {
48 die "Only one role supported at a time by with" if @_ > 1;
49 $me->apply_role_to_package($target, $_[0]);
51 # grab all *non-constant* (stash slot is not a scalarref) subs present
52 # in the symbol table and store their refaddrs (no need to forcibly
53 # inflate constant subs into real subs) - also add '' to here (this
55 @{$INFO{$target}{not_methods}={}}{
56 '', map { *$_{CODE}||() } grep !ref($_), values %$stash
59 $APPLIED_TO{$target} = { $target => undef };
62 sub apply_role_to_package {
63 my ($me, $to, $role) = @_;
67 die "This is apply_role_to_package" if ref($to);
68 die "${role} is not a Role::Tiny" unless my $info = $INFO{$role};
70 $me->_check_requires($to, $role, @{$info->{requires}||[]});
72 $me->_install_methods($to, $role);
74 $me->_install_modifiers($to, $info->{modifiers});
76 # only add does() method to classes and only if they don't have one
77 if (not $INFO{$to} and not $to->can('does')) {
78 *{_getglob "${to}::does"} = \&does_role;
81 # copy our role list into the target's
82 @{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = ();
85 sub apply_roles_to_object {
86 my ($me, $object, @roles) = @_;
87 die "No roles supplied!" unless @roles;
88 my $class = ref($object);
89 bless($object, $me->create_class_with_roles($class, @roles));
93 sub create_class_with_roles {
94 my ($me, $superclass, @roles) = @_;
96 die "No roles supplied!" unless @roles;
99 '__WITH__', $superclass, my $compose_name = join '__AND__', @roles
102 return $new_name if $COMPOSED{class}{$new_name};
104 foreach my $role (@roles) {
106 die "${role} is not a Role::Tiny" unless my $info = $INFO{$role};
110 { local $@; require mro; }
112 { local $@; require MRO::Compat; }
115 my @composable = map $me->_composable_package_for($_), reverse @roles;
117 *{_getglob("${new_name}::ISA")} = [ @composable, $superclass ];
119 my @info = map +($INFO{$_} ? $INFO{$_} : ()), @roles;
121 $me->_check_requires(
122 $new_name, $compose_name,
123 do { my %h; @h{map @{$_->{requires}||[]}, @info} = (); keys %h }
126 *{_getglob "${new_name}::does"} = \&does_role unless $new_name->can('does');
128 @{$APPLIED_TO{$new_name}||={}}{
129 map keys %{$APPLIED_TO{$_}}, @roles
132 $COMPOSED{class}{$new_name} = 1;
136 sub _composable_package_for {
137 my ($me, $role) = @_;
138 my $composed_name = 'Role::Tiny::_COMPOSABLE::'.$role;
139 return $composed_name if $COMPOSED{role}{$composed_name};
140 $me->_install_methods($composed_name, $role);
141 my $base_name = $composed_name.'::_BASE';
142 *{_getglob("${composed_name}::ISA")} = [ $base_name ];
143 my $modifiers = $INFO{$role}{modifiers}||[];
145 foreach my $modified (
146 do { my %h; @h{map $_->[1], @$modifiers} = (); keys %h }
148 push @mod_base, "sub ${modified} { shift->next::method(\@_) }";
152 eval(my $code = join "\n", "package ${base_name};", @mod_base);
153 die "Evaling failed: $@\nTrying to eval:\n${code}" if $@;
155 $me->_install_modifiers($composed_name, $modifiers);
156 $COMPOSED{role}{$composed_name} = 1;
157 return $composed_name;
160 sub _check_requires {
161 my ($me, $to, $name, @requires) = @_;
162 if (my @requires_fail = grep !$to->can($_), @requires) {
163 # role -> role, add to requires, role -> class, error out
164 if (my $to_info = $INFO{$to}) {
165 push @{$to_info->{requires}||=[]}, @requires_fail;
167 die "Can't apply ${name} to ${to} - missing ".join(', ', @requires_fail);
172 sub _concrete_methods_of {
173 my ($me, $role) = @_;
174 my $info = $INFO{$role};
175 $info->{methods} ||= do {
176 # grab role symbol table
177 my $stash = do { no strict 'refs'; \%{"${role}::"}};
178 my $not_methods = $info->{not_methods};
180 # grab all code entries that aren't in the not_methods list
182 my $code = *{$stash->{$_}}{CODE};
183 # rely on the '' key we added in import for "no code here"
184 exists $not_methods->{$code||''} ? () : ($_ => $code)
185 } grep !ref($stash->{$_}), keys %$stash
190 sub methods_provided_by {
191 my ($me, $role) = @_;
192 die "${role} is not a Role::Tiny" unless my $info = $INFO{$role};
193 (keys %{$me->_concrete_methods_of($role)}, @{$info->{requires}||[]});
196 sub _install_methods {
197 my ($me, $to, $role) = @_;
199 my $info = $INFO{$role};
201 my $methods = $me->_concrete_methods_of($role);
203 # grab target symbol table
204 my $stash = do { no strict 'refs'; \%{"${to}::"}};
206 # determine already extant methods of target
209 +(ref($stash->{$_}) || *{$stash->{$_}}{CODE}),
213 foreach my $i (grep !exists $has_methods{$_}, keys %$methods) {
215 *{_getglob "${to}::${i}"} = $methods->{$i};
219 sub _install_modifiers {
220 my ($me, $to, $modifiers) = @_;
221 if (my $info = $INFO{$to}) {
222 push @{$info->{modifiers}}, @{$modifiers||[]};
224 foreach my $modifier (@{$modifiers||[]}) {
225 $me->_install_single_modifier($to, @$modifier);
230 sub _install_single_modifier {
231 my ($me, @args) = @_;
232 Class::Method::Modifiers::install_modifier(@args);
236 my ($proto, $role) = @_;
237 return exists $APPLIED_TO{ref($proto)||$proto}{$role};
244 Role::Tiny - Roles. Like a nouvelle cusine portion size slice of Moose.
262 use Role::Tiny::With;
264 # bar gets imported, but not foo
273 C<Role::Tiny> is a minimalist role composition tool.
275 =head1 ROLE COMPOSITION
277 Role composition can be thought of as much more clever and meaningful multiple
278 inheritance. The basics of this implementation of roles is:
284 If a method is already defined on a class, that method will not be composed in
289 If a method that the role L</requires> to be implemented is not implemented,
290 role application will fail loudly.
294 Unlike L<Class::C3>, where the B<last> class inherited from "wins," role
295 composition is the other way around, where first wins. In a more complete
296 system (see L<Moose>) roles are checked to see if they clash. The goal of this
297 is to be much simpler, hence disallowing composition of multiple roles at once.
301 =head2 apply_role_to_package
303 Role::Tiny->apply_role_to_package('Some::Package', 'Some::Role');
305 Composes role with package. See also L<Role::Tiny::With>.
307 =head2 apply_roles_to_object
309 Role::Tiny->apply_roles_to_object($foo, qw(Some::Role1 Some::Role2));
311 Composes roles in order into object directly. Object is reblessed into the
314 =head2 create_class_with_roles
316 Role::Tiny->create_class_with_roles('Some::Base', qw(Some::Role1 Some::Role2));
318 Creates a new class based on base, with the roles composed into it in order.
319 New class is returned.
325 if (Role::Tiny::does_role($foo, 'Some::Role')) {
329 Returns true if class has been composed with role.
331 This subroutine is also installed as ->does on any class a Role::Tiny is
332 composed into unless that class already has an ->does method, so
334 if ($foo->does_role('Some::Role')) {
338 will work for classes but to test a role, one must use ::does_role directly
340 =head1 IMPORTED SUBROUTINES
344 requires qw(foo bar);
346 Declares a list of methods that must be defined to compose role.
353 Composes another role into the current role. Only one role may be composed in
354 at a time to allow the code to remain as simple as possible.
358 before foo => sub { ... };
360 See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full
365 around foo => sub { ... };
367 See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full
372 after foo => sub { ... };
374 See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full
379 See L<Moo> for authors.
381 =head1 COPYRIGHT AND LICENSE
383 See L<Moo> for the copyright and license.