Question

我正在尝试扩展Set :: Object以便在插入对象时允许类型约束检查。到目前为止，我的班级看起来像这样：

package My::Set::Object;

use strict;
use warnings;

use Moose;
use MooseX::NonMoose;
extends 'Set::Object';

has type => (is => 'ro', isa => 'Str', required => 1);

before [ qw(insert invert intersection union) ] => sub {
my ($self,$list) = @_;

for (@$list) {
    confess "Only ",$self->type," objects are allowed " unless $_->does($self->type);
}
};

no Moose;
__PACKAGE__->meta->make_immutable;

不幸的是，当我执行以下示例对象构造时，似乎构造参数也传递给Set :: Object

my $set = My::Set::Object->new(type => 'Foo::Bar');

打印出set的内容后，我发现＆＃34;键入＆＃34;和＆＃34; Foo :: Bar＆＃34;是该集的成员。

我该如何解决这个问题？或者是否有更简单的方法可以做到这一点？

Answer 1

这里，作为一个实际答案。我通常按照这些方式进行编码，并且应该做你需要的。警告：我没有测试过这段代码，它甚至可能无法编译，但它应该让你走上正轨。与此子类化的唯一真正区别是 - ＆gt;检查'Set :: Object'时，My :: Set :: Object对象上的ISA不会成立。

package My::Set::Object;

use strict;
use warnings;

use Moose;
use Set::Object;

my @methods = qw/insert includes has contains invert intersection union/; # etc etc.

has type => (is => 'ro', isa => 'Str', required => 1);
has _so => (is => 'ro', isa => 'Set::Object', handles => \@methods, lazy_build => 1);

before [ qw(insert invert intersection union) ] => sub {
  my ($self,$list) = @_;

  for (@$list) {
    confess "Only ",$self->type," objects are allowed " unless $_->does($self->type);
  }
};

sub _build__so {
  return Set::Object->new()
}
no Moose;
__PACKAGE__->meta->make_immutable;

具有类型约束检查的Set :: Object

1 个答案: