如何在Perl中将数组用作对象属性？

发布时间：2020-12-15 21:51:37 所属栏目：大数据来源：网络整理

导读：我需要一些关于Perl中数组的帮助这是我的构造函数. BuildPacket.pm sub new { my $class = shift; my $Packet = { _PacketName = shift,_Platform = shift,_Version = shift,_IncludePath = [@_],}; bless $Packet,$class; return $Packet; } sub SetPacket

我需要一些关于Perl中数组的帮助

这是我的构造函数.

BuildPacket.pm

sub new {
            my $class = shift;    
            my $Packet = {
                _PacketName => shift,_Platform  => shift,_Version => shift,_IncludePath => [@_],};

            bless $Packet,$class;
            return $Packet;
        }

        sub SetPacketName {
            my ( $Packet,$PacketName ) = @_;
            $Packet->{_PacketName} = $PacketName if defined($PacketName);
            return $Packet->{_PacketName};
        }

       sub SetIncludePath {
            my ( $Packet,@IncludePath ) = @_;
            $Packet->{_IncludePath} = @IncludePath;
        }

         sub GetPacketName {
            my( $Packet ) = @_;
            return $Packet->{_PacketName};
        }

        sub GetIncludePath {
           my( $Packet ) = @_;
           @{ $Packet->{_IncludePath} };
        }

(代码已经根据’gbacon’的建议进行了修改,谢谢)

我以动态的方式将相对路径推入’includeobjects’数组.正在从xml文件中读取包含路径并将其推送到此数组中.

# PacketInput.pm
if($element eq 'Include')
            {
             while( my( $key,$value ) = each( %attrs ))
                {
                if($key eq 'Path')
                    push(@includeobjects,$value);
                        }
                }

所以,includeobject将是这样的：

@includeobjects = (
    "./input/myMockPacketName","./input/myPacket/my3/*.txt","./input/myPacket/in.html",);

我正在使用此行来设置包含路径

$newPacket->SetIncludePath(@includeobjects);

同样在PacketInput.pm中,我有

sub CreateStringPath
{
    my $packet = shift;
    print "printing packet in CreateStringPath".$packet."n";
    my $append = "";
    my @arr = @{$packet->GetIncludePath()};
    foreach my $inc (@arr)
    {
        $append = $append + $inc;
        print "print append :".$append."n";
    }
}

我有很多数据包,所以我循环遍历每个数据包

# PacketCreation.pl
my @packets = PacketInput::GetPackets();
foreach my $packet (PacketInput::GetPackets())
{
    print "printing packet in loop packet".$packet."n";
    PacketInput::CreateStringPath($packet);
    $packet->CreateTar($platform,$input);
    $packet->GetValidateOutputFile($platform);
}

get和set方法适用于PacketName.但由于IncludePath是一个数组,我无法使它工作,我的意思是相对路径没有打印.

解决方法

如果启用strict pragma,则代码甚至无法编译：

Global symbol "@_IncludePath" requires explicit package name at Packet.pm line 15.
Global symbol "@_IncludePath" requires explicit package name at Packet.pm line 29.
Global symbol "@_IncludePath" requires explicit package name at Packet.pm line 30.
Global symbol "@_IncludePath" requires explicit package name at Packet.pm line 40.

不要在密钥中使用@ unquoted,因为它会使解析器混淆.我建议完全删除它们,以免混淆人类读者的代码.

您似乎想要将所有属性值从参数拉到构造函数,因此继续使用shift剥离标量值,然后剩下的一切必须是包含路径.

我假设包含路径的组件将是简单的标量而不是引用;如果后者是这种情况,那么你将需要为安全制作深层副本.

sub new {
  my $class = shift;

  my $Packet = {
    _PacketName  => shift,_Platform    => shift,_Version     => shift,_IncludePath => [ @_ ],};

  bless $Packet,$class;
}

请注意,不需要将受祝福的对象存储在临时变量中,然后由于semantics of Perl subs而立即返回它：

If no return is found and if the last statement is an expression,its value is returned.

以下方法也将使用此功能.

给定上面的构造函数,GetIncludePath成为

sub GetIncludePath {
  my( $Packet ) = @_;
  my @path = @{ $Packet->{_IncludePath} };
  wantarray ? @path : @path;
}

这里有几件事情.首先,请注意我们要小心返回包含路径的副本,而不是直接引用内部数组.这样,用户可以修改从GetIncludePath返回的值,而不必担心丢弃数据包的状态.

wantarray operator允许子确定其呼叫的上下文并相应地做出响应.在列表上下文中,GetIncludePath将返回数组中的值列表.否则,它返回对数组副本的引用.这样,客户端代码可以像在中一样调用它

foreach my $path (@{ $packet->GetIncludePath }) { ... }

要么

foreach my $path ($packet->GetIncludePath) { ... }

然后是SetIncludePath

sub SetIncludePath {
  my ( $Packet,@IncludePath ) = @_;
  $Packet->{_IncludePath} = @IncludePath;
}

请注意,您可能在构造函数中使用了类似的代码,而不是一次删除一个带有shift的参数.

您可以使用上面定义的类,如

#! /usr/bin/perl

use strict;
use warnings;

use Packet;

sub print_packet {
  my($p) = @_;
  print $p->GetPacketName,"n",map("  - [$_]n",$p->GetIncludePath),"n";
}

my $p = Packet->new("MyName","platform","v1.0",qw/ foo bar baz /);
print_packet $p;

my @includeobjects = (
    "./input/myMockPacketName",);
$p->SetIncludePath(@includeobjects);
print_packet $p;

print "In scalar context:n";
foreach my $path (@{ $p->GetIncludePath }) {
  print $path,"n";
}

输出：

MyName
  - [foo]
  - [bar]
  - [baz]

MyName
  - [./input/myMockPacketName]
  - [./input/myPacket/my3/*.txt]
  - [./input/myPacket/in.html]

In scalar context:
./input/myMockPacketName
./input/myPacket/my3/*.txt
./input/myPacket/in.html

（编辑：李大同）

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