[英]How can I use a variable as a module name in Perl?
I know it is possible to use a variable as a variable name for package variables in Perl. 我知道可以在Perl中使用变量作为包变量的变量名。 I would like to use the contents of a variable as a module name. 我想使用变量的内容作为模块名称。 For instance: 例如:
package Foo;
our @names =("blah1", "blah2");
1;
And in another file I want to be able be able to set the contents of a scalar to "foo" and then access the names array in Foo
through that scalar. 在另一个文件中,我希望能够将标量的内容设置为“foo”,然后通过该标量访问Foo
的names数组。
my $packageName = "Foo";
Essentially I want to do something along the lines of: 基本上我想做的事情是:
@{$packageName}::names; #This obviously doesn't work.
I know I can use 我知道我可以使用
my $names = eval '$'. $packageName . "::names"
But only if Foo::names
is a scalar. 但只有当Foo::names
是标量时。 Is there another way to do this without the eval
statement? 没有eval
语句,还有另一种方法吗?
To get at package variables in package $package
, you can use symbolic references: 要获取包$package
中的包变量,可以使用符号引用:
no strict 'refs';
my $package = 'Foo';
# grab @Foo::names
my @names = @{ $package . '::names' }
A better way, which avoids symbolic references, is to expose a method within Foo
that will return the array. 避免符号引用的更好方法是在Foo
中公开将返回数组的方法。 This works because the method invocation operator ( ->
) can take a string as the invocant. 这是因为方法调用操作符( ->
)可以将字符串作为调用者。
package Foo;
our @names = ( ... );
sub get_names {
return @names;
}
package main;
use strict;
my $package = 'Foo';
my @names = $package->get_names;
Strict checking is preventing you from using a variable (or literal string) as part of a name, but this can be disabled locally: 严格检查会阻止您将变量(或文字字符串)用作名称的一部分,但可以在本地禁用它:
my @values;
{
no strict 'refs';
@values = @{"Mypackage"}::var;
}
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