use strict;
use warnings FATAL => 'all';
-our $VERSION = '1.000000'; # 1.0.0
+our $VERSION = '1.003002';
$VERSION = eval $VERSION;
our %INFO;
our %APPLIED_TO;
our %COMPOSED;
+our %COMPOSITE_INFO;
# Module state workaround totally stolen from Zefram's Module::Runtime.
sub import {
my $target = caller;
my $me = shift;
- strictures->import;
- return if $INFO{$target}; # already exported into this package
+ strict->import;
+ warnings->import(FATAL => 'all');
+ return if $me->is_role($target); # already exported into this package
+ $INFO{$target}{is_role} = 1;
# get symbol table reference
- my $stash = do { no strict 'refs'; \%{"${target}::"} };
+ my $stash = _getstash($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}||=[]}, [ $type => @_ ];
+ return;
};
}
*{_getglob "${target}::requires"} = sub {
push @{$INFO{$target}{requires}||=[]}, @_;
+ return;
};
*{_getglob "${target}::with"} = sub {
- die "Only one role supported at a time by with" if @_ > 1;
- $me->apply_role_to_package($target, $_[0]);
+ $me->apply_roles_to_package($target, @_);
+ return;
};
# 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 { *$_{CODE}||() } grep !ref($_), values %$stash
- } = ();
+ # inflate constant subs into real subs) with a map to the coderefs in
+ # case of copying or re-use
+ my @not_methods = (map { *$_{CODE}||() } grep !ref($_), values %$stash);
+ @{$INFO{$target}{not_methods}={}}{@not_methods} = @not_methods;
# a role does itself
$APPLIED_TO{$target} = { $target => undef };
}
-sub apply_role_to_package {
+sub role_application_steps {
+ qw(_install_methods _check_requires _install_modifiers _copy_applied_list);
+}
+
+sub apply_single_role_to_package {
my ($me, $to, $role) = @_;
_load_module($role);
die "This is apply_role_to_package" if ref($to);
- die "${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, $info->{modifiers});
+ die "${role} is not a Role::Tiny" unless $me->is_role($role);
- # 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;
+ foreach my $step ($me->role_application_steps) {
+ $me->$step($to, $role);
}
+}
+sub _copy_applied_list {
+ my ($me, $to, $role) = @_;
# copy our role list into the target's
@{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = ();
}
my ($me, $object, @roles) = @_;
die "No roles supplied!" unless @roles;
my $class = ref($object);
- bless($object, $me->create_class_with_roles($class, @roles));
- $object;
+ # on perl < 5.8.9, magic isn't copied to all ref copies. bless the parameter
+ # directly, so at least the variable passed to us will get any magic applied
+ bless($_[1], $me->create_class_with_roles($class, @roles));
}
-sub create_class_with_roles {
+my $role_suffix = 'A000';
+sub _composite_name {
my ($me, $superclass, @roles) = @_;
- die "No roles supplied!" unless @roles;
-
my $new_name = join(
'__WITH__', $superclass, my $compose_name = join '__AND__', @roles
);
+ if (length($new_name) > 252) {
+ $new_name = $COMPOSED{abbrev}{$new_name}
+ ||= substr($new_name, 0, 250 - length $role_suffix).'__'.$role_suffix++;
+ }
+ return wantarray ? ($new_name, $compose_name) : $new_name;
+}
+
+sub create_class_with_roles {
+ my ($me, $superclass, @roles) = @_;
+
+ die "No roles supplied!" unless @roles;
+
+ _load_module($superclass);
+ {
+ my %seen;
+ $seen{$_}++ for @roles;
+ if (my @dupes = grep $seen{$_} > 1, @roles) {
+ die "Duplicated roles: ".join(', ', @dupes);
+ }
+ }
+
+ my ($new_name, $compose_name) = $me->_composite_name($superclass, @roles);
+
return $new_name if $COMPOSED{class}{$new_name};
foreach my $role (@roles) {
_load_module($role);
- die "${role} is not a Role::Tiny" unless my $info = $INFO{$role};
+ die "${role} is not a Role::Tiny" unless $me->is_role($role);
}
if ($] >= 5.010) {
require MRO::Compat;
}
- my @composable = map $me->_composable_package_for($_), reverse @roles;
+ my $composite_info = $me->_composite_info_for(@roles);
+ my %conflicts = %{$composite_info->{conflicts}};
+ if (keys %conflicts) {
+ my $fail =
+ join "\n",
+ map {
+ "Method name conflict for '$_' between roles "
+ ."'".join(' and ', sort values %{$conflicts{$_}})."'"
+ .", cannot apply these simultaneously to an object."
+ } keys %conflicts;
+ die $fail;
+ }
- *{_getglob("${new_name}::ISA")} = [ @composable, $superclass ];
+ my @composable = map $me->_composable_package_for($_), reverse @roles;
- my @info = map +($INFO{$_} ? $INFO{$_} : ()), @roles;
+ # some methods may not exist in the role, but get generated by
+ # _composable_package_for (Moose accessors via Moo). filter out anything
+ # provided by the composable packages, excluding the subs we generated to
+ # make modifiers work.
+ my @requires = grep {
+ my $method = $_;
+ !grep $_->can($method) && !$COMPOSED{role}{$_}{modifiers_only}{$method},
+ @composable
+ } @{$composite_info->{requires}};
$me->_check_requires(
- $new_name, $compose_name,
- do { my %h; @h{map @{$_->{requires}||[]}, @info} = (); keys %h }
+ $superclass, $compose_name, \@requires
);
- *{_getglob "${new_name}::does"} = \&does_role unless $new_name->can('does');
+ *{_getglob("${new_name}::ISA")} = [ @composable, $superclass ];
@{$APPLIED_TO{$new_name}||={}}{
map keys %{$APPLIED_TO{$_}}, @roles
return $new_name;
}
+# preserved for compat, and apply_roles_to_package calls it to allow an
+# updated Role::Tiny to use a non-updated Moo::Role
+
+sub apply_role_to_package { shift->apply_single_role_to_package(@_) }
+
+sub apply_roles_to_package {
+ my ($me, $to, @roles) = @_;
+
+ return $me->apply_role_to_package($to, $roles[0]) if @roles == 1;
+
+ my %conflicts = %{$me->_composite_info_for(@roles)->{conflicts}};
+ my @have = grep $to->can($_), keys %conflicts;
+ delete @conflicts{@have};
+
+ if (keys %conflicts) {
+ my $fail =
+ join "\n",
+ map {
+ "Due to a method name conflict between roles "
+ ."'".join(' and ', sort values %{$conflicts{$_}})."'"
+ .", the method '$_' must be implemented by '${to}'"
+ } keys %conflicts;
+ die $fail;
+ }
+
+ # conflicting methods are supposed to be treated as required by the
+ # composed role. we don't have an actual composed role, but because
+ # we know the target class already provides them, we can instead
+ # pretend that the roles don't do for the duration of application.
+ my @role_methods = map $me->_concrete_methods_of($_), @roles;
+ # separate loops, since local ..., delete ... for ...; creates a scope
+ local @{$_}{@have} for @role_methods;
+ delete @{$_}{@have} for @role_methods;
+
+ # the if guard here is essential since otherwise we accidentally create
+ # a $INFO for something that isn't a Role::Tiny (or Moo::Role) because
+ # autovivification hates us and wants us to die()
+ if ($INFO{$to}) {
+ delete $INFO{$to}{methods}; # reset since we're about to add methods
+ }
+
+ # backcompat: allow subclasses to use apply_single_role_to_package
+ # to apply changes. set a local var so ours does nothing.
+ our %BACKCOMPAT_HACK;
+ if($me ne __PACKAGE__
+ and exists $BACKCOMPAT_HACK{$me} ? $BACKCOMPAT_HACK{$me} :
+ $BACKCOMPAT_HACK{$me} =
+ $me->can('role_application_steps')
+ == \&role_application_steps
+ && $me->can('apply_single_role_to_package')
+ != \&apply_single_role_to_package
+ ) {
+ foreach my $role (@roles) {
+ $me->apply_single_role_to_package($to, $role);
+ }
+ }
+ else {
+ foreach my $step ($me->role_application_steps) {
+ foreach my $role (@roles) {
+ $me->$step($to, $role);
+ }
+ }
+ }
+ $APPLIED_TO{$to}{join('|',@roles)} = 1;
+}
+
+sub _composite_info_for {
+ my ($me, @roles) = @_;
+ $COMPOSITE_INFO{join('|', sort @roles)} ||= do {
+ foreach my $role (@roles) {
+ _load_module($role);
+ }
+ my %methods;
+ foreach my $role (@roles) {
+ my $this_methods = $me->_concrete_methods_of($role);
+ $methods{$_}{$this_methods->{$_}} = $role for keys %$this_methods;
+ }
+ my %requires;
+ @requires{map @{$INFO{$_}{requires}||[]}, @roles} = ();
+ delete $requires{$_} for keys %methods;
+ delete $methods{$_} for grep keys(%{$methods{$_}}) == 1, keys %methods;
+ +{ conflicts => \%methods, requires => [keys %requires] }
+ };
+}
+
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")} = [ $base_name ];
+ # force stash to exist so ->can doesn't complain
+ _getstash($base_name);
+ # Not using _getglob, since setting @ISA via the typeglob breaks
+ # inheritance on 5.10.0 if the stash has previously been accessed an
+ # then a method called on the class (in that order!), which
+ # ->_install_methods (with the help of ->_install_does) ends up doing.
+ { no strict 'refs'; @{"${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 }
- ) {
+ my @modifiers = grep !$composed_name->can($_),
+ do { my %h; @h{map @{$_}[1..$#$_-1], @$modifiers} = (); keys %h };
+ foreach my $modified (@modifiers) {
push @mod_base, "sub ${modified} { shift->next::method(\@_) }";
}
+ my $e;
{
local $@;
eval(my $code = join "\n", "package ${base_name};", @mod_base);
- die "Evaling failed: $@\nTrying to eval:\n${code}" if $@;
+ $e = "Evaling failed: $@\nTrying to eval:\n${code}" if $@;
}
- $me->_install_modifiers($composed_name, $modifiers);
- $COMPOSED{role}{$composed_name} = 1;
+ die $e if $e;
+ $me->_install_modifiers($composed_name, $role);
+ $COMPOSED{role}{$composed_name} = {
+ modifiers_only => { map { $_ => 1 } @modifiers },
+ };
return $composed_name;
}
sub _check_requires {
- my ($me, $to, $name, @requires) = @_;
+ my ($me, $to, $name, $requires) = @_;
+ return unless my @requires = @{$requires||$INFO{$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}) {
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};
- +{
- # grab all code entries that aren't in the not_methods list
- map {
- my $code = *{$stash->{$_}}{CODE};
- # rely on the '' key we added in import for "no code here"
- exists $not_methods->{$code||''} ? () : ($_ => $code)
- } grep !ref($stash->{$_}), keys %$stash
- };
+ # grab role symbol table
+ my $stash = _getstash($role);
+ # reverse so our keys become the values (captured coderefs) in case
+ # they got copied or re-used since
+ my $not_methods = { reverse %{$info->{not_methods}||{}} };
+ $info->{methods} ||= +{
+ # grab all code entries that aren't in the not_methods list
+ map {
+ my $code = *{$stash->{$_}}{CODE};
+ ( ! $code or exists $not_methods->{$code} ) ? () : ($_ => $code)
+ } grep !ref($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)}, @{$info->{requires}||[]});
+ die "${role} is not a Role::Tiny" unless $me->is_role($role);
+ (keys %{$me->_concrete_methods_of($role)}, @{$INFO{$role}->{requires}||[]});
}
sub _install_methods {
my $methods = $me->_concrete_methods_of($role);
# grab target symbol table
- my $stash = do { no strict 'refs'; \%{"${to}::"}};
+ my $stash = _getstash($to);
# determine already extant methods of target
my %has_methods;
foreach my $i (grep !exists $has_methods{$_}, keys %$methods) {
no warnings 'once';
- *{_getglob "${to}::${i}"} = $methods->{$i};
+ my $glob = _getglob "${to}::${i}";
+ *$glob = $methods->{$i};
+
+ # overloads using method names have the method stored in the scalar slot
+ # and &overload::nil in the code slot.
+ next
+ unless $i =~ /^\(/
+ && defined &overload::nil
+ && $methods->{$i} == \&overload::nil;
+
+ my $overload = ${ *{_getglob "${role}::${i}"}{SCALAR} };
+ next
+ unless defined $overload;
+
+ *$glob = \$overload;
}
+
+ $me->_install_does($to);
}
sub _install_modifiers {
- my ($me, $to, $modifiers) = @_;
+ my ($me, $to, $name) = @_;
+ return unless my $modifiers = $INFO{$name}{modifiers};
if (my $info = $INFO{$to}) {
push @{$info->{modifiers}}, @{$modifiers||[]};
} else {
}
}
+my $vcheck_error;
+
sub _install_single_modifier {
my ($me, @args) = @_;
+ defined($vcheck_error) or $vcheck_error = do {
+ local $@;
+ eval { Class::Method::Modifiers->VERSION(1.05); 1 }
+ ? 0
+ : $@
+ };
+ $vcheck_error and die $vcheck_error;
Class::Method::Modifiers::install_modifier(@args);
}
+my $FALLBACK = sub { 0 };
+sub _install_does {
+ my ($me, $to) = @_;
+
+ # only add does() method to classes
+ return if $me->is_role($to);
+
+ # add does() only if they don't have one
+ *{_getglob "${to}::does"} = \&does_role unless $to->can('does');
+
+ return
+ if $to->can('DOES') and $to->can('DOES') != (UNIVERSAL->can('DOES') || 0);
+
+ my $existing = $to->can('DOES') || $to->can('isa') || $FALLBACK;
+ my $new_sub = sub {
+ my ($proto, $role) = @_;
+ Role::Tiny::does_role($proto, $role) or $proto->$existing($role);
+ };
+ no warnings 'redefine';
+ *{_getglob "${to}::DOES"} = $new_sub;
+}
+
sub does_role {
my ($proto, $role) = @_;
- return exists $APPLIED_TO{ref($proto)||$proto}{$role};
+ if ($] >= 5.010) {
+ require mro;
+ } else {
+ require MRO::Compat;
+ }
+ foreach my $class (@{mro::get_linear_isa(ref($proto)||$proto)}) {
+ return 1 if exists $APPLIED_TO{$class}{$role};
+ }
+ return 0;
+}
+
+sub is_role {
+ my ($me, $role) = @_;
+ return !!($INFO{$role} && $INFO{$role}{is_role});
}
1;
+=encoding utf-8
+
=head1 NAME
-Role::Tiny - Roles. Like a nouvelle cusine portion size slice of Moose.
+Role::Tiny - Roles. Like a nouvelle cuisine portion size slice of Moose.
=head1 SYNOPSIS
sub bar { ... }
+ around baz => sub { ... }
+
1;
else where
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.
=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.
+composition is the other way around, where the class wins. If multiple roles
+are applied in a single call (single with statement), then if any of their
+provided methods clash, an exception is raised unless the class provides
+a method since this conflict indicates a potential problem.
-=head1 METHODS
+=head1 IMPORTED SUBROUTINES
-=head2 apply_role_to_package
+=head2 requires
- Role::Tiny->apply_role_to_package('Some::Package', 'Some::Role');
+ requires qw(foo bar);
-Composes role with package. See also L<Role::Tiny::With>.
+Declares a list of methods that must be defined to compose role.
-=head2 apply_roles_to_object
+=head2 with
- Role::Tiny->apply_roles_to_object($foo, qw(Some::Role1 Some::Role2));
+ with 'Some::Role1';
-Composes roles in order into object directly. Object is reblessed into the
-resulting class.
+ with 'Some::Role1', 'Some::Role2';
-=head2 create_class_with_roles
+Composes another role into the current role (or class via L<Role::Tiny::With>).
- Role::Tiny->create_class_with_roles('Some::Base', qw(Some::Role1 Some::Role2));
+If you have conflicts and want to resolve them in favour of Some::Role1 you
+can instead write:
-Creates a new class based on base, with the roles composed into it in order.
-New class is returned.
+ with 'Some::Role1';
+ with 'Some::Role2';
+
+If you have conflicts and want to resolve different conflicts in favour of
+different roles, please refactor your codebase.
+
+=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>.
+
+=head2 Strict and Warnings
+
+In addition to importing subroutines, using C<Role::Tiny> applies L<strict> and
+L<fatal warnings|perllexwarn/Fatal Warnings> to the caller. It's possible to
+disable these if desired:
+
+ use Role::Tiny;
+ use warnings NONFATAL => 'all';
=head1 SUBROUTINES
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_role('Some::Role')) {
+ if ($foo->does('Some::Role')) {
...
}
-will work for classes but to test a role, one must use ::does_role directly
+will work for classes but to test a role, one must use ::does_role directly.
-=head1 IMPORTED SUBROUTINES
+Additionally, Role::Tiny will override the standard Perl C<DOES> method
+for your class. However, if C<any> class in your class' inheritance
+hierarchy provides C<DOES>, then Role::Tiny will not override it.
-=head2 requires
+=head1 METHODS
- requires qw(foo bar);
+=head2 apply_roles_to_package
-Declares a list of methods that must be defined to compose role.
+ Role::Tiny->apply_roles_to_package(
+ 'Some::Package', 'Some::Role', 'Some::Other::Role'
+ );
-=head2 with
+Composes role with package. See also L<Role::Tiny::With>.
- with 'Some::Role1';
- with 'Some::Role2';
+=head2 apply_roles_to_object
-Composes another role into the current role. Only one role may be composed in
-at a time to allow the code to remain as simple as possible.
+ Role::Tiny->apply_roles_to_object($foo, qw(Some::Role1 Some::Role2));
-=head2 before
+Composes roles in order into object directly. Object is reblessed into the
+resulting class.
- before foo => sub { ... };
+=head2 create_class_with_roles
-See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full
-documentation.
+ Role::Tiny->create_class_with_roles('Some::Base', qw(Some::Role1 Some::Role2));
-=head2 around
+Creates a new class based on base, with the roles composed into it in order.
+New class is returned.
- around foo => sub { ... };
+=head2 is_role
-See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full
-documentation.
+ Role::Tiny->is_role('Some::Role1')
-=head2 after
+Returns true if the given package is a role.
- after foo => sub { ... };
+=head1 CAVEATS
-See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full
-documentation.
+=over 4
+
+=item * On perl 5.8.8 and earlier, applying a role to an object won't apply any
+overloads from the role to all copies of the object.
+
+=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 don't find the additional
+restrictions to be amazingly helpful in most cases; L<Role::Basic>'s choices
+are more a guide to what you should prefer doing, to our mind, rather than
+something that needs to be enforced.
=head1 AUTHOR
perigrin - Chris Prather (cpan:PERIGRIN) <chris@prather.org>
+Mithaldu - Christian Walde (cpan:MITHALDU) <walde.christian@googlemail.com>
+
+ilmari - Dagfinn Ilmari Mannsåker (cpan:ILMARI) <ilmari@ilmari.org>
+
+tobyink - Toby Inkster (cpan:TOBYINK) <tobyink@cpan.org>
+
+haarg - Graham Knop (cpan:HAARG) <haarg@haarg.org>
+
=head1 COPYRIGHT
Copyright (c) 2010-2012 the Role::Tiny L</AUTHOR> and L</CONTRIBUTORS>
projects / gitmo/Role-Tiny.git / blobdiff