如何在Perl中用子元素覆盖父类函数? [英] How can I override a parent class function with child one in Perl?

问题描述

我想替换子类中的父函数(Somefunc)，所以当我调用Main过程时，它会失败.

I would like to replace parent function (Somefunc) in child class, so when I call Main procedure it should fail.

在Perl中可以吗?

代码:

package Test;

use strict;
use warnings;

sub Main()
{
    SomeFunc() or die "Somefunc returned 0";
}

sub SomeFunc()
{
    return 1;
}

package Test2;

use strict;
use warnings;

our @ISA = ("Test");

sub SomeFunc()
{
    return 0;
}

package main;

Test2->Main();

推荐答案

调用Test2->Main()时，程序包名称作为第一个参数传递给被调用函数.您可以使用该参数来解决正确的功能.

When you call Test2->Main(), the package name is passed as the first parameter to the called function. You can use the parameter to address the right function.

sub Main
{
    my ($class) = @_;
    $class->SomeFunc() or die "Somefunc returned 0";
}

在此示例中，$class将为"Test2"，因此您将调用Test2->SomeFunc().更好的解决方案是使用实例(即Test::new中的bless对象，使用$self而不是$class).甚至更好的方法是使用 Moose ，它可以解决Perl中的面向对象编程存在很多问题.

In this example, $class will be "Test2", so you will call Test2->SomeFunc(). Even better solution would be to use instances (i.e., bless the object in Test::new, use $self instead of $class). And even better would be to use Moose, which solves a lot of problems with object-oriented programming in Perl.

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