在使用 perl 包时将参数传递给它 [英] Passing arguments to a perl package while using it

问题描述

如何在使用包时传递一些参数，例如:

How to pass some arguments while using a package, for example:

use Test::More tests => 21;   

我找不到有关此功能的任何有价值的文档.传递这样的论点有什么利弊吗?

I wasn't able to find any valuable documentation about this featue. Are there any pros and cons of passing such arguments?

推荐答案

useMy::Module LIST 做了两件事:1) 它 requires My::Module;和 2) 调用 My::Module->import(LIST).

use My::Module LIST does two things: 1) It requires My::Module; and 2) Invokes My::Module->import(LIST).

因此，您可以编写模块的 import 例程来处理以您想要的任何方式传递的参数列表.如果您确实正在编写一个不向调用者的命名空间导出任何内容的面向对象的模块，这将变得更加容易.

Therefore, you can write your module's import routine to treat the list of arguments passed any which way you want. This becomes even easier if you are indeed writing an object oriented module that does not export anything to the caller's namespace.

这是一个毫无意义的例子:

Here's a rather pointless example:

package Ex;

use strict;
use warnings;

{
    my $hello = 'Hello';
    sub import {
        my $self = shift;
        my $lang = shift || 'English';
        if ($lang eq 'Turkish') {
            $hello = 'Merhaba';
        }
        else {
            $hello = 'Hello';
        }
        return;
    }

    sub say_hello {
        my $self = shift;
        my $name = shift;

        print "$hello $name!\n";
        return;
    }
}

__PACKAGE__;
__END__

以及使用它的脚本:

#!/usr/bin/env perl

use strict;
use warnings;

use Ex 'Turkish';
Ex->say_hello('Perl');

Ex->import;
Ex->say_hello('Perl');

输出:

$ ./imp.pl
Merhaba Perl!
Hello Perl!

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