Moose::Role による Trait の解説。社内勉強会資料です。

1. Trait Moose::Role
2009 5 8

2. : Moose::Role
Perl Java interface
✤
requires API
✤
with API
✤
Perl gihyo.jp
✤
Trait
✤

3. : Mix-in (1)
✤
3
( Linux 2005 7 )
Mix-in Lisp
✤

4. : Mix-in (2)
Mix-in
✤
✤
Mix-in
✤
Mix-in
✤
✤
✤

5. : Mix-in (3)
Ruby
SuperClass
module MixinA
def mixin1
MixinB
print quot;Hello Mixin Anquot;
end
end
SubClass
module MixinC
def mixin2
MixinA
MixinC
mixin1
print quot;Hello Mixin Cnquot;
end
SubSubClass
end
MixinA
class SubSubClass < SubClass
include MixinA
include MixinC
end
SuperClass2
SubSubClass.new.mixin2

6. Trait
OOP
✤
Mix-in
✤
2002 Traits: Composable Units of Behavior
✤

7. Trait
Perl 5(Moose) Perl 6
✤
JavaScript(Joose)
✤
Java(Scala)
✤
Ruby (module Mix-in )
✤
Fortress 2006 sun
✤
Smalltalk, PHP, ActionScript 3.0
✤

8. Trait Mix-in
Flatten
✤
(Perl Exporter )
✤
= Trait
✤
(with, import)
✤
Trait =
✤
Trait ( )
✤

9. Moose::Role Trait
(provided)
✤
(required)
✤
( OK)
✤
package TaxRole;
TaxRole
use Moose::Role;
requires 'price';
comsumption_tax price
our $TAX_RATE = 0.05;
tax_inclusive_price
sub consumption_tax{
return shift->price * $TAX_RATE;
}
sub tax_inclusive_price{
my $self = shift;
return $self->price + $self->consumption_tax;
}
no Moose::Role;

10. Moose::Role Trait
Trait
✤
required
✤
Goods
package Goods;
use Moose;
price
has price => (
isa => 'Int',
TaxRole
is => 'ro',
required => 1,
comsumption_tax price
);
tax_inclusive_price
with 'TaxRole';
no Moose;

11. Trait
sum : t1 + t2
✤
alias : t[a→b]
✤
exclusion : t - a
✤

12. Trait (1) - sum
package TraitsA;
required + provided = provided
✤
use Moose::Role;
required + required = required
✤
with 'TraitsB';
provided + provided = required ( )
✤
no Moose::Role;
TraitA TraitB TraitA
+= a ⇒
a c d b a
b d c c d

13. sum : ...
(m, ⊥: ,⟙: ) m1 ⊔ ⟙ = ⟙
→ ✤
✤
⟘⊔⟙=⟙
✤
⟘ ⊔⟘=⟘
✤
⟙⊔⟙=⟙
✤
m1 ⊔ ⟘ = m1
✤
provided: ⊥ ⟙
✤
m1 ⊔ m1 = m1
✤
m1 ⊔ m2 = ⟙ required: - provided
✤ ✤
TraitA TraitB TraitA
+= a = m3, c = m4 ⇒
a = m1, b = m2 b = m2, c = m4
c = ⟘, d = ⟘ d=⟘ a = ⟙, d = ⟘

14. Trait (2) - alias
package AnotherTraits;
use Moose::Role;
→
✤
with 'TraitsA' => {
alias => {a => 'e'},
};
no Moose::Role;
TraitA TraitA
[e → a] ⇒
a c a c
b d b d
e

15. Trait (3) - exclusion
package AnotherTraits;
use Moose::Role;
−
✤
with 'TraitsA' => {
excludes => ['a'],
};
no Moose::Role;
TraitA TraitA
-= a ⇒
a c b c
b d d

16. Trait :
package TraitsA;
use Moose::Role;
TraitA
with 'TraitsB' => {
a b
alias => {b => 'e'},
excludes => ['c'], c
}; d
e
no Moose::Role;
TraitA TraitB
a d += ( b a [e → b] - c )
b c
c d

17. Trait :
package TraitsA;
use Moose::Role;
TraitA
with 'TraitsB' => {
a b
alias => {b => 'e'},
excludes => ['c'], c
}; d
e
no Moose::Role;
TraitA TraitB
+= ( b = e
a d a [e → b] - c )
=
b c
c d

18. Trait
✤
package Trait; package Class;
use Moose::Role; use Moose;
sub class_vs_trait{ print __PACKAGE__, quot;nquot;; } extends 'SuperClass'; with 'Trait';
sub super_vs_trait{ print __PACKAGE__, quot;nquot;; } sub class_vs_trait{ print __PACKAGE__, quot;nquot;; }
no Moose::Role; no Moose;
package SuperClass; package main;
use Moose; my $c = Class->new;
sub super_vs_trait{ print __PACKAGE__, quot;nquot;; } $c->class_vs_trait;
no Moose; $c->super_vs_trait;

19. Class 1 SuperClass 1 (∵ )
✤
Trait Trait
⇒
Trait required
✤
(Mix-in )
⇒
✤
✤
alias exclusion
✤

20. package TraitA;
use Moose::Role; package Class;
sub vs{ print __PACKAGE__, quot;nquot; } use Moose;
no Moose::Role; with 'TraitA', 'TraitB';
no Moose;
package TraitB;
use Moose::Role; package main;
sub vs{ print __PACKAGE__, quot;nquot; } Class->new->vs;
no Moose::Role;

21. Trait
state( ) Trait
✤
→ has
✤
Trait
✤
→
✤

22. ✤
Trait
✤
Trait Mix-in
✤