我正在尝试专门模仿 code found here,，这个属性:
# web-scraper object
has 'worker' => (
is => 'ro',
isa => 'Web::Scraper',
default => sub {
scraper(sub { });
}
);
但是当我将相同的代码放入我的类(class)时，我收到以下错误:
Not a HASH reference at accessor MyModule::scraper
这是我的代码:
has 'scraper' => (is => 'rw', isa => 'Web::Scraper', default => sub { scraper( sub { } ); });
以下是 Moose 的更多错误:
# There were 1 warning(s)
# Previous test 0 ''
# You are overwriting a locally defined function (scraper) with an accessor at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose/Meta/Attribute.pm line 1047, <DATA> line 1.
# Moose::Meta::Attribute::_process_accessors(Moose::Meta::Attribute=HASH(0x3b19838), "accessor", "scraper", undef) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Class/MOP/Attribute.pm line 445
# Class::MOP::Attribute::install_accessors(Moose::Meta::Attribute=HASH(0x3b19838)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose/Meta/Attribute.pm line 994
# Moose::Meta::Attribute::install_accessors(Moose::Meta::Attribute=HASH(0x3b19838)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Class/MOP/Class.pm line 897
# Class::MOP::Class::try {...} () called at /usr/share/perl5/Try/Tiny.pm line 81
# eval {...} called at /usr/share/perl5/Try/Tiny.pm line 72
# Try::Tiny::try(CODE(0x3b076f0), Try::Tiny::Catch=REF(0x3b195e0)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Class/MOP/Class.pm line 902
# Class::MOP::Class::_post_add_attribute(Moose::Meta::Class=HASH(0x349f920), Moose::Meta::Attribute=HASH(0x3b19838)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Class/MOP/Mixin/HasAttributes.pm line 38
# Class::MOP::Mixin::HasAttributes::add_attribute(Moose::Meta::Class=HASH(0x349f920), Moose::Meta::Attribute=HASH(0x3b19838)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose/Meta/Class.pm line 573
# Moose::Meta::Class::add_attribute(Moose::Meta::Class=HASH(0x349f920), "scraper", "definition_context", HASH(0x2921ce8), "is", "rw", "isa", "Web::Scraper", "default", ...) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose.pm line 76
# Moose::has(Moose::Meta::Class=HASH(0x349f920), "scraper", "is", "rw", "isa", "Web::Scraper", "default", CODE(0x3ae1a60)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose/Exporter.pm line 408
# Moose::has("scraper", "is", "rw", "isa", "Web::Scraper", "default", CODE(0x3ae1a60)) called at /home/steve/perl/perl-lib/LaborData/DataFetcher.pm line 33
# require LaborData/DataFetcher.pm called at ./labor_data.t line 27
# main::BEGIN() called at /home/steve/perl/perl-lib/LaborData/DataFetcher.pm line 0
# eval {...} called at /home/steve/perl/perl-lib/LaborData/DataFetcher.pm line 0
# at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose/Meta/Attribute.pm line 1047, <DATA> line 1.
# Moose::Meta::Attribute::_process_accessors(Moose::Meta::Attribute=HASH(0x3b19838), "accessor", "scraper", undef) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Class/MOP/Attribute.pm line 445
# Class::MOP::Attribute::install_accessors(Moose::Meta::Attribute=HASH(0x3b19838)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose/Meta/Attribute.pm line 994
# Moose::Meta::Attribute::install_accessors(Moose::Meta::Attribute=HASH(0x3b19838)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Class/MOP/Class.pm line 897
# Class::MOP::Class::try {...} () called at /usr/share/perl5/Try/Tiny.pm line 81
# eval {...} called at /usr/share/perl5/Try/Tiny.pm line 72
# Try::Tiny::try(CODE(0x3b076f0), Try::Tiny::Catch=REF(0x3b195e0)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Class/MOP/Class.pm line 902
# Class::MOP::Class::_post_add_attribute(Moose::Meta::Class=HASH(0x349f920), Moose::Meta::Attribute=HASH(0x3b19838)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Class/MOP/Mixin/HasAttributes.pm line 38
# Class::MOP::Mixin::HasAttributes::add_attribute(Moose::Meta::Class=HASH(0x349f920), Moose::Meta::Attribute=HASH(0x3b19838)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose/Meta/Class.pm line 573
# Moose::Meta::Class::add_attribute(Moose::Meta::Class=HASH(0x349f920), "scraper", "definition_context", HASH(0x2921ce8), "is", "rw", "isa", "Web::Scraper", "default", ...) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose.pm line 76
# Moose::has(Moose::Meta::Class=HASH(0x349f920), "scraper", "is", "rw", "isa", "Web::Scraper", "default", CODE(0x3ae1a60)) called at /usr/lib/x86_64-linux-gnu/perl5/5.20/Moose/Exporter.pm line 408
# Moose::has("scraper", "is", "rw", "isa", "Web::Scraper", "default", CODE(0x3ae1a60)) called at /home/steve/perl/perl-lib/LaborData/DataFetcher.pm line 33
# require LaborData/DataFetcher.pm called at ./labor_data.t line 27
# main::BEGIN() called at /home/steve/perl/perl-lib/LaborData/DataFetcher.pm line 0
# eval {...} called at /home/steve/perl/perl-lib/LaborData/DataFetcher.pm line 0
#
最佳答案
您遇到了从 scraper 导入的 Web::Scraper 函数和 scraper 定义的 has 'scraper' => ... 访问器方法之间的名称冲突。这就是警告 You are overwriting a locally defined function (scraper) with an accessor 所指的内容。
您的代码当前的编写方式，您的默认初始值设定项 scraper( sub { } ); 最终会直接调用访问器方法，该方法会立即死亡，因为它期望一个对象作为其第一个参数，而不是 sub { } 。
解决此问题的最简单方法是重命名您的属性。不幸的是，其他方法更难，因为 Web::Scraper 不支持重命名或抑制其导出的符号。
以下代码未经测试，但如果您想保持属性名称不变，它可能会起作用:
use Moose;
use Web::Scraper;
BEGIN { *_web_scraper = \&scraper; undef &scraper; }
has 'scraper' => (
is => 'ro',
isa => 'Web::Scraper',
default => sub {
_web_scraper(sub { });
},
);
关于perl - 在 Moose 中创建一个 Web::Scraper 对象作为类属性，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/41967068/