X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FRole%2FTiny.pm;h=e5e3e1f4cfa1b7cc4c18cd5b32d57da32c8eec74;hb=836aea1b0290aacce8730f1fa4c49fd085b36696;hp=1a4cf9cd5c0c0122e5575717f2aee64e3fc1a0cd;hpb=fb5074f642700cbf0ebed591d9eb3d186ef6f198;p=gitmo%2FRole-Tiny.git diff --git a/lib/Role/Tiny.pm b/lib/Role/Tiny.pm index 1a4cf9c..e5e3e1f 100644 --- a/lib/Role/Tiny.pm +++ b/lib/Role/Tiny.pm @@ -1,25 +1,49 @@ package Role::Tiny; +sub _getglob { \*{$_[0]} } +sub _getstash { \%{"$_[0]::"} } + use strict; use warnings FATAL => 'all'; +our $VERSION = '1.000_900'; # 1.0.900 +$VERSION = eval $VERSION; + our %INFO; our %APPLIED_TO; our %COMPOSED; +our %COMPOSITE_INFO; + +# Module state workaround totally stolen from Zefram's Module::Runtime. + +BEGIN { + *_WORK_AROUND_BROKEN_MODULE_STATE = "$]" < 5.009 ? sub(){1} : sub(){0}; +} -sub _getglob { no strict 'refs'; \*{$_[0]} } +sub Role::Tiny::__GUARD__::DESTROY { + delete $INC{$_[0]->[0]} if @{$_[0]}; +} sub _load_module { - return 1 if $_[0]->can('can'); (my $proto = $_[0]) =~ s/::/\//g; - require "${proto}.pm"; + $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; - my $me = $_[0]; - 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 @@ -33,22 +57,21 @@ sub import { push @{$INFO{$target}{requires}||=[]}, @_; }; *{_getglob "${target}::with"} = sub { - die "Only one role supported at a time by with" if @_ > 1; - $me->apply_role_to_package($_[0], $target); + $me->apply_roles_to_package($target, @_); }; - # 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} = { $target => undef }; } -sub apply_role_to_package { - my ($me, $role, $to) = @_; +sub apply_single_role_to_package { + my ($me, $to, $role) = @_; _load_module($role); @@ -83,15 +106,26 @@ sub create_class_with_roles { die "No roles supplied!" unless @roles; - my $new_name = join('+', $superclass, my $compose_name = join '+', @roles); + { + my %seen; + $seen{$_}++ for @roles; + if (my @dupes = grep $seen{$_} > 1, @roles) { + die "Duplicated roles: ".join(', ', @dupes); + } + } + + 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 my $info = $INFO{$role}; + die "${role} is not a Role::Tiny" unless $INFO{$role}; } - if ($] > 5.010) { + if ($] >= 5.010) { require mro; } else { require MRO::Compat; @@ -101,7 +135,7 @@ sub create_class_with_roles { *{_getglob("${new_name}::ISA")} = [ @composable, $superclass ]; - my @info = map +($INFO{$_} ? $INFO{$_} : ()), @roles; + my @info = map $INFO{$_}, @roles; $me->_check_requires( $new_name, $compose_name, @@ -118,6 +152,43 @@ sub create_class_with_roles { return $new_name; } +sub apply_role_to_package { shift->apply_single_role_to_package(@_) } + +sub apply_roles_to_package { + my ($me, $to, @roles) = @_; + + return $me->apply_single_role_to_package($to, $roles[0]) if @roles == 1; + + my %conflicts = %{$me->_composite_info_for(@roles)->{conflicts}}; + delete $conflicts{$_} for $me->_concrete_methods_of($to); + 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; + } + $me->apply_single_role_to_package($to, $_) for @roles; + $APPLIED_TO{$to}{join('|',@roles)} = 1; +} + +sub _composite_info_for { + my ($me, @roles) = @_; + $COMPOSITE_INFO{join('|', sort @roles)} ||= do { + _load_module($_) for @roles; + my %methods; + foreach my $role (@roles) { + my $this_methods = $me->_concrete_methods_of($role); + $methods{$_}{$this_methods->{$_}} = $role for keys %$this_methods; + } + delete $methods{$_} for grep keys(%{$methods{$_}}) == 1, keys %methods; + +{ conflicts => \%methods } + }; +} + sub _composable_package_for { my ($me, $role) = @_; my $composed_name = 'Role::Tiny::_COMPOSABLE::'.$role; @@ -132,8 +203,13 @@ sub _composable_package_for { ) { push @mod_base, "sub ${modified} { shift->next::method(\@_) }"; } - eval(my $code = join "\n", "package ${base_name};", @mod_base); - die "Evaling failed: $@\nTrying to eval:\n${code}" if $@; + 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 $composed_name; @@ -154,18 +230,16 @@ sub _check_requires { sub _concrete_methods_of { my ($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->{$_}) eq 'SCALAR'), keys %$stash - }; + # 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 }; } @@ -188,7 +262,7 @@ sub _install_methods { # determine already extant methods of target my %has_methods; @has_methods{grep - +((ref($stash->{$_}) eq 'SCALAR') || (*{$stash->{$_}}{CODE})), + +(ref($stash->{$_}) || *{$stash->{$_}}{CODE}), keys %$stash } = (); @@ -200,14 +274,240 @@ sub _install_methods { sub _install_modifiers { my ($me, $to, $modifiers) = @_; - foreach my $modifier (@{$modifiers||[]}) { - Class::Method::Modifiers::install_modifier($to, @{$modifier}); + if (my $info = $INFO{$to}) { + push @{$info->{modifiers}}, @{$modifiers||[]}; + } else { + foreach my $modifier (@{$modifiers||[]}) { + $me->_install_single_modifier($to, @$modifier); + } } } +sub _install_single_modifier { + my ($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. + +=head1 DESCRIPTION + +C 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 to be implemented is not implemented, +role application will fail loudly. + +=back + +Unlike L, where the B class inherited from "wins," role +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 + +=head2 apply_roles_to_package + + Role::Tiny->apply_roles_to_package( + 'Some::Package', 'Some::Role', 'Some::Other::Role' + ); + +Composes role with package. See also L. + +=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::Role1', 'Some::Role2'; + +Composes another role into the current role (or class via L). + +If you have conflicts and want to resolve them in favour of Some::Role1 you +can instead write: + + 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 is lazily loaded and we do not declare it as +a dependency. If your L role uses modifiers you must depend on +both L and L. + +=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 is lazily loaded and we do not declare it as +a dependency. If your L role uses modifiers you must depend on +both L and L. + +=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 is lazily loaded and we do not declare it as +a dependency. If your L role uses modifiers you must depend on +both L and L. + +=head1 SEE ALSO + +L is the attribute-less subset of L; L is +a meta-protocol-less subset of the king of role systems, L. + +If you don't want method modifiers and do want to be forcibly restricted +to a single role application per class, Ovid's L exists. But +Stevan Little (the L author) don't find the additional restrictions +to be amazingly helpful in most cases; L'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 + +mst - Matt S. Trout (cpan:MSTROUT) + +=head1 CONTRIBUTORS + +dg - David Leadbeater (cpan:DGL) + +frew - Arthur Axel "fREW" Schmidt (cpan:FREW) + +hobbs - Andrew Rodland (cpan:ARODLAND) + +jnap - John Napiorkowski (cpan:JJNAPIORK) + +ribasushi - Peter Rabbitson (cpan:RIBASUSHI) + +chip - Chip Salzenberg (cpan:CHIPS) + +ajgb - Alex J. G. Burzyński (cpan:AJGB) + +doy - Jesse Luehrs (cpan:DOY) + +perigrin - Chris Prather (cpan:PERIGRIN) + +=head1 COPYRIGHT + +Copyright (c) 2010-2012 the Role::Tiny L and L +as listed above. + +=head1 LICENSE + +This library is free software and may be distributed under the same terms +as perl itself. + +=cut