驼鹿还是元？

发布于 2024-07-14 22:52:19 字数 1108 浏览 8 评论 0原文

我已经尝试了多种方法来做到这一点，但没有一种方法看起来足够优雅。（我也想知道 CPAN 或 Moose 是否已经有了这个。随着时间的推移，我所做的数十次搜索都没有显示出任何完全匹配的内容。）

我想创建一种类，它

是 Base + Facade + Factory 的其他类型将自身加载为目标类型的类。
“工厂”只是Base->new( %params )，它根据各个子类注册的策略创建类型。
每个子类都知道有关基类的域的基本知识，但我试图将其保持在最低限度。请参阅下面的示例：UnresolvedPath 只知道我们应该首先检查是否存在。

一个明显的例子是文件系统目录和文件：

package Path;
use Moose;

...

sub BUILD { 
    my ( $self, $params ) = @_;
    my $path = $params->{path};

    my $class_name;
    foreach my $test_sub ( @tests ) { 
        $class_name = $test_sub->( $path );
        last if $class_name;
    }
    croak "No valid class for $path!" unless defined $class_name;
    $class_name->BUILD( $self, $params );
}

package Folder; 
use Moose;

extends 'Path';

use Path register => selector => sub { -d $_[0] };

sub BUILD { ... }

package UnresolvedPath; 

extends 'Path';

use Path register position => 1, selector => sub { !-e $_[0] };

问题：Moose 是否为此提供了一个优雅的解决方案？或者我是否必须进入 Class::MOP 进行批量处理？

原文

I've been trying to do this a number of ways, but none of them seem graceful enough. (I'm also wondering if CPAN or Moose already has this. The dozens of searches I've done over time have shown nothing that quite matches.)

I want to create a type of class that

is a Base + Facade + Factory for other classes which load themselves as destination types.
The "factory" is just Base->new( %params ) and this creates types based on policies registered by the individual subclass.
Each subclass knows basic things about the domain of the Base class, but I'm trying to keep it minimal. See the example below: UnresolvedPath just knows that we should check for existence first.

The obvious example for this is file system directories and files:

package Path;
use Moose;

...

sub BUILD { 
    my ( $self, $params ) = @_;
    my $path = $params->{path};

    my $class_name;
    foreach my $test_sub ( @tests ) { 
        $class_name = $test_sub->( $path );
        last if $class_name;
    }
    croak "No valid class for $path!" unless defined $class_name;
    $class_name->BUILD( $self, $params );
}

package Folder; 
use Moose;

extends 'Path';

use Path register => selector => sub { -d $_[0] };

sub BUILD { ... }

package UnresolvedPath; 

extends 'Path';

use Path register position => 1, selector => sub { !-e $_[0] };