如何在Perl中使用变量作为模块名称? [英] How can I use a variable as a module name in Perl?

问题描述

我知道可以在Perl中将变量用作包变量的变量名.我想将变量的内容用作模块名称.例如:

I know it is possible to use a variable as a variable name for package variables in Perl. I would like to use the contents of a variable as a module name. For instance:

package Foo;
our @names =("blah1", "blah2");
1;

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中的名称数组.

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.

my $packageName = "Foo";

基本上，我想按照以下方式做某事:

Essentially I want to do something along the lines of:

@{$packageName}::names; #This obviously doesn't work.

我知道我可以使用

my $names = eval '$'. $packageName . "::names" 

但仅当Foo::names是标量时.如果没有eval语句，还有另一种方法吗?

But only if Foo::names is a scalar. Is there another way to do this without the eval statement?

推荐答案

要获取包$package中的包变量，可以使用符号引用:

To get at package variables in package $package, you can use symbolic references:

no strict 'refs';
my $package = 'Foo';

# grab @Foo::names
my @names = @{ $package . '::names' }

避免符号引用的更好方法是在Foo中公开一个将返回数组的方法.之所以可行，是因为方法调用运算符(->)可以将字符串作为调用者.

A better way, which avoids symbolic references, is to expose a method within Foo that will return the array. This works because the method invocation operator (->) can take a string as the invocant.

package Foo;

our @names = ( ... );
sub get_names { 
    return @names;
}

package main;
use strict;

my $package = 'Foo';
my @names = $package->get_names;

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