PHP：Hook类，用于删除内联HTML并包含在另一个类中

May be my question title is not so well to discribe, since I am confuse what to say this :( hope any moderator will help to write the right title.

Here I have one core class containing all core methods with inline HTML. The system allows to override methods by extending the core_class using theme_class, but I cannot remove inline HTML since the page renders with those tags.

So I am looking for some hook where I can extends the core_class methods with different class (hook_class) and rewrite all methods without inlne HTML and return the value. Than I can instanciate that into HTML/PHP file and use own markup.

Once HTML/PHP is ready than I include it into theme_class somewhere. The system only consider theme_class as a theme file which allows to override core_class method.

So in short I am trying to too take out all inline HTML from core_class and create HTML/PHP for theme and than include theme files to theme_class which is extending the core_class.

So is there any way which allows me to do what I am looking for?

System Core Class

class core_class
{

    function class_method1()
    {
        // all php code including inline html
    }

    function class_method2()
    {
        // all php code including inline html
    }

    function class_method3()
    {
        // all php code including inline html
    }

}

System Theme Class extends Core Class

class theme_class extends core_class
{

    function class_method1()
    {
        // all override code for the method
    }

    function class_method2()
    {
        // all override code for the method
    }

    function class_method3()
    {
        // all override code for the method
    }

}