函数传递后的对象的Dereference数组

Question

我对取消引用的东西很奇怪。

在我的程序oobjtest中，我想得到一个对象列表。

步骤:在perl 1中)调用类方法@lo_hashref_objects = oclass::getemall()；。打印出来。

步骤:在perl类中

1. 调用另一个类方法来获取文件
2. 按引用在数组my @lol中拆分后存储的内容行
3. 通过返回@lol将这个数组传递给getemall函数。列表-数据可通过$array_ref->$i访问
4. 创建一个$self = oclass->new；的新对象。通过Setter函数将数据放入实例变量中。
5. 对象工作，请参见Getter函数输出。
6. 将对象存储在数组中。可通过$self和数组寻址获得的对象数据，请参阅getemall
7. 把它传递给testprog oobjtest
8. 从列表中获取数据，我的@lol失败了。缺乏语法知识，但我无法解决它。

类文件

    package oclass;

    use warnings;
    use strict;
    use Carp;
    # to make your class data a file-scoped lexical
    my $Census = 0;

    use feature qw/say switch/;
    use lib qw(/home/hj/lib/perl/oo/test);
    our $verb_file = '/home/hj/lib/perl/oo/test/data/verb.txt';
    #-----------------------------------------------------------
    sub new 
    {
        my $class = shift;
        my $self = {};
    
        $self->{bez} = undef;
        $self->{etym} = undef;

        # "private" data
        $self->{"_CENSUS"} = \$Census;

        bless ($self, $class);
        ++ ${ $self->{"_CENSUS"} };
        return $self;
    }


    # class method
    sub _get_file_content
    {
        my ($class_name) = @_;
        open my $fh, "<:encoding(UTF-8)", $verb_file or die;
        my @lol = ();
        while (<$fh>) {
            chomp;
            # gather lines per reference in list lol
            push @lol, [ split ' & ' ];   
        }
        close $fh or croak "Couldn't close '$verb_file': $Carp::OS_ERROR";  
        for my $array_ref ( @lol ) {
            print "DEBUG _get_file_content: lol\t  @$array_ref , \n";
            for (my $i = 0; $i <= $#$array_ref; $i++) {
                say "$i: ", $array_ref->[$i];
            }
        }
        return @lol;   
    } # end _get_file_content


    sub getemall
    {
        my @lol = ();
        my @lo_hashref_objects = ();
        @lol = oclass::_get_file_content();

        for my $array_ref ( @lol ) {
            print "getemall: lol\t  @$array_ref , \n";
            for (my $i = 0; $i <= $#$array_ref; $i++) {
                say "$i: ", $array_ref->[$i];
            }
        }
    
        my $i = 0;
        for my $array_ref ( @lol ) {
            my $self = oclass->new;
            $self->setbez($array_ref->[0]);
            $self->setetym($array_ref->[1]);
            say $self->getbez;
            say $self->getetym;
    
            push @lo_hashref_objects, $self;
    
            print "getemall:CCC", $lo_hashref_objects[$i]->getbez, " \n";
            print "getemakk: C1C1C1: ", $lo_hashref_objects[$i]->getetym, " \n";
            $i++;
        }

        return @lo_hashref_objects;
    } # end getemall

    #-----------------------------------------------------------
    sub getbez {
        my $self = shift;
        return $self->{bez};
    }
    sub setbez {
        my ($self, $bez) = @_;
            croak('Usage: $self->setbez($bez)') if @_ < 2;
            $self->{bez}= $bez;
        return;
    }

    sub setetym {
        my $self = shift;
        if (@_) { @{ $self->{etym} } = @_ }
        return @{ $self->{etym} };
    }   
    sub getetym {
        my $self = shift;
        return @{ $self->{etym} };
    }

    1; # so the require or use succeeds

测试程序

    #!/usr/bin/perl
    #
    use warnings;
    use strict;
    use Carp;

    use lib qw(/home/hj/lib/perl/oo/test);

    use oclass;

    ### call the class method "getemall" to gather all the single lines in  file (data)
    my @lo_hashref_objects = oclass::getemall();
    my $i=0;
    for my $obj_ref ( @lo_hashref_objects ) {
        print " \nafter call of getemall: $obj_ref \n";
        print "after call of getemall: $obj_ref->getbez \n";
        print "ref obj_ref: ", ref($obj_ref), "\n";
        print "after call of getemall: $obj_ref \n";
        print "afterlo_hashref_object: $lo_hashref_objects[$i++]->getbez \n";

        print "after call of getemall: $obj_ref->getetym \n";
    }

部分输出

     der
    Versuch
    getemall:CCC der 
    getemakk: C1C1C1: Versuch 
    die
    Verbindung
    getemall:CCC die 
    getemakk: C1C1C1: Verbindung 

    after call of getemall: oclass=HASH(0x55f70e320278) 
    after call of getemall: oclass=HASH(0x55f70e320278)->getbez 
    ref obj_ref: oclass
    after call of getemall: oclass=HASH(0x55f70e320278) 
    afterlo_hashref_object: oclass=HASH(0x55f70e320278)->getbez 
    
    hj@debian:~$ 

Answer 1

不能以这种方式调用字符串中的方法--内插。

print "after call of getemall: $obj_ref->getbez \n";

将产生

after call of getemall: oclass=HASH(0x55f70e320278)->getbez 

解决这一问题的一种方法是使用

print "after call of getemall: " . $obj_ref->getbez. " \n";

另一种方法是使用“婴儿车”

print "after call of getemall: @{[$obj_ref->getbez]} \n";

两者都应该正确调用该方法并显示数据。