如何迭代這個Perl結構？

鑑於下面的代碼，我想弄清楚如何遍歷哈希引用數組（或者至少我認爲它是一個哈希引用數組）。那就是$Policy->rules()？如何迭代這個Perl結構？

也許有創建一個結構數組的更好方法，我願意提供建議。

use Class::Struct; 
use Data::Dumper; 

struct Policy => {   
    listings => '@', # Will treat like rules eventually.  
    rules  => '@', # an array of rules  
}; 

struct Rule => {     
    direction => '$',   
    id   => '$',   
}; 

$policy = Policy->new(); 

$rule1 = Rule->new(); 
$rule1->direction('Any'); 
$rule1->id(1); 

$rule2 = Rule->new(); 
$rule2->direction('Inbound'); 
$rule2->id(2); 

$rule3 = Rule->new(); 
$rule3->direction('Outbound'); 
$rule3->id(3); 

push($policy->rules(),$rule1); 
push($policy->rules(),$rule2); 
push($policy->rules(),$rule3); 

$Data::Dumper::Indent = $Data::Dumper::Terse = 1; 
print Dumper \$policy;

輸出：

\bless({ 
    'Policy::listings' => [], 
    'Policy::rules' => [ 
     bless({ 
     'Rule::id' => 1, 
     'Rule::direction' => 'Any' 
     }, 'Rule'), 
     bless({ 
     'Rule::id' => 2, 
     'Rule::direction' => 'Inbound' 
     }, 'Rule'), 
     bless({ 
     'Rule::id' => 3, 
     'Rule::direction' => 'Outbound' 
     }, 'Rule') 
    ] 
    }, 'Policy')

來源

2012-08-30 user1637240

visit_policy($policy); 

sub visit_policy { 
    my ($policy) = @_; 

    my $listings = $policy->listings; 
    my $rules = $policy->rules; 

    for my $listing (@$listings) { 
     visit_listing($listing); 
    } 

    for my $rule (@$rules) { 
     visit_rule($rule); 
    } 
} 

sub visit_listing { 
    my ($listing) = @_; 
    # ... 
} 

sub visit_rule { 
    my ($rule) = @_; 

    my $direction = $rule->direction; 
    my $id  = $rule->id; 

    # ... 
}

來源

2012-08-30 22:08:44 ikegami

嗨，謝謝你的幫忙。我不得不調整一下。 Visit_listing（）被稱爲2x。在將visit_rule更改爲獲取$ rule-> direction和$ rule-> id之後，當它嘗試解析$ rule-> direction時，出現以下錯誤：無法在第66行的未指向引用上調用方法「direction」。 – user1637240

應用您提到的修復程序。測試它。不要得到你得到的錯誤，也不要對你提供的信息有意義。 – ikegami

我如何獲得參考祝福？ – user1637240

感謝您的幫助。它看起來很接近，但它仍然需要一些微調。見下文。現在，當我運行它並嘗試打印rule-> id時，我得到以下內容：

無法在D：/ SLC/Aiken/Policy/POC/OLAP/test上調用未指向引用的方法「方向」。 pl line 66.

visit_policy($policy); 

sub visit_policy { 
    my ($policy) = @_; 

    my $listings = $policy->listings; 
    my $rules = $policy->rules; 

    for my $listing (@$listings) { 
     visit_listing($listing); 
    } 

    for my $rule (@$rules) { 
     visit_rule($rules); 
    } 
} 

sub visit_listing { 
    my ($listing) = @_; 
    # ... 
} 

sub visit_rule { 
    my ($rule) = @_; 

    my $direction = $rule->direction; #<-- Line 66 
    my $id  = $rule->id; 

    print $id . "\n"; 

    # ... 
}

來源

2012-08-31 14:02:33 user1637240

如何迭代這個Perl結構？

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