Question

假设我有两个对象$obj1和$obj2，它们都是Moose类的实例。我想知道以下哪项适用：

$obj1的课程与$obj2的相同;
$obj1的类是$obj2的子类;
$obj1的类是$obj2的超类;
对象的类都不是另一个的子类。

我该怎么做？

Answer 1

$obj1的班级与$obj2的班级相同吗？
```
ref $obj1 eq ref $obj2;
```
$obj1的类是$obj2的子类吗？
```
$obj1->isa(ref $obj2);
```
$obj1的班级是$obj2的超类吗？
```
$obj2->isa(ref $obj1);
```
对象的类都不是另一个的子类。

见上文。

更新

回应有关在运行时应用的角色的评论：

package My::X;

use Moose; use namespace::autoclean;

sub boo { }

__PACKAGE__->meta->make_immutable;

package My::Y;

use Moose; use namespace::autoclean;

extends 'My::X';

__PACKAGE__->meta->make_immutable;

package My::Z;

use Moose::Role; use namespace::autoclean;

requires 'boo';

package main;

use Test::More tests => 2;

use Moose::Util qw( apply_all_roles );

my $x = My::X->new;
my $y = My::Y->new;

ok($y->isa(ref $x), 'Before role was applied at runtime');

apply_all_roles($x, 'My::Z');

ok($y->isa(ref $x), 'After role was applied at runtime');

输出：

1..2
ok 1 - Before role was applied at runtime
not ok 2 - After role was applied at runtime
#   Failed test 'After role was applied at runtime' at C:\Temp\t.pl line 36.
# Looks like you failed 1 test of 2.

Answer 2

使用Class::MOP中的Moose基础，您可以反省所有这些信息。

例如：

{
    package Daddy;
    use Moose;
}

{
    package Kid;
    use Moose;
    extends 'Daddy';
}

my $son      = Kid->new;
my $daughter = Kid->new;

my $sons_class                  = ($son->meta->class_precedence_list)[0];
my $daughters_class             = ($daughter->meta->class_precedence_list)[0];

my @sons_subclasses             = $son->meta->subclasses;     # or better...
my @daughters_subclasses        = $daughter->meta->direct_subclasses;

my @sons_superclasses           = $son->meta->superclasses;

my @Daddies_children            = Daddy->meta->direct_subclasses;

另请参阅此SO问题/答案How can I find all the packages that inherit from a package in Perl?

/ I3az /

在Moose中，我如何判断一个对象的类是否是另一个对象类的子类？

2 个答案:

更新