PHP extension development: How to use abstract classes to implement inheritance of custom functions?

In PHP extensions, the method of using abstract classes to implement custom function inheritance is as follows: define abstract classes, specify function signatures and documents; create subclasses to implement specific functions; register custom functions in extension modules; create subclasses to support different conversion; register custom functions for PHP code to call.

Use abstract classes in PHP extensions to implement custom function inheritance

In PHP extension development, abstract classes are a Powerful tool that allows you to create custom functions and implement inheritance in a modular way. Below we will demonstrate how to use abstract classes to implement inheritance in custom functions and provide a practical case.

The role of abstract classes

Abstract classes define a set of methods without providing actual implementations. Subclasses must override these methods to create a complete and usable class. This means you can define a public interface and let subclasses provide the specific details.

Using abstract classes to implement custom function inheritance

In order to implement inheritance in a custom function, you can follow the steps below:

1. Create an abstract class, define function signatures and documentation:

abstract class CustomFunction {
    /**
     * 执行自定义函数
     *
     * @param mixed $args 函数参数
     * @return mixed 函数返回值
     */
    public abstract function __invoke(...$args);
}

2. Create subclasses to implement concrete functions:

class ExampleCustomFunction extends CustomFunction {
    public function __invoke(...$args) {
        // 自定义函数的具体实现
    }
}

3. In the extension module Register a custom function:

function register_custom_function(string $name) {
    // 通过函数名获取自定义函数类
    $functionClass = "ExampleCustomFunction";
    // 注册函数到扩展中
    php_register_named_function($name, $functionClass, ...);
}

Practical case: Custom string conversion function

To show how to use abstract classes to implement inheritance, let us create a custom Define string conversion function:

1. Create abstract class:

abstract class StringTransformer {
    /**
     * 转换字符串
     *
     * @param string $string 要转换的字符串
     * @return string 转换后的字符串
     */
    public abstract function transformString(string $string);
}

2. Create subclass:

class ToUpperCaseTransformer extends StringTransformer {
    public function transformString(string $string) {
        return strtoupper($string);
    }
}

class ToLowerCaseTransformer extends StringTransformer {
    public function transformString(string $string) {
        return strtolower($string);
    }
}

3. Register custom functions:

function register_string_transform_functions() {
    register_custom_function("str_toupper", "ToUpperCaseTransformer");
    register_custom_function("str_tolower", "ToLowerCaseTransformer");
}

Now you can use the str_toupper and str_tolower functions in your PHP code to convert strings , and you can easily add more subclasses to support additional transformations.

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