$ This-> $ function () in PHP what does it mean? How can this problem be solved?

$ This-& gt; $ function () in PHP? Dear friends, recently, my younger brother is reading the code of daily group buying. The result is in modulesindex. mod. php shows the following code: PHPcodefunctionModuleObject ($ config) {$ this-& gt; MasterObject ($ config); $ this-> $ function () what does it mean in PHP?
Dear friends, recently, my younger brother is reading the code of group buying every day. The result shows this code in/modules/index. mod. php:

PHP code

  function ModuleObject( $config )    {        $this->MasterObject($config);        $runCode = Load::moduleCode($this);        $this->$runCode();    }

In the fifth line of code, $ this-> $ runCode (); does this sentence have any special meaning in PHP? I am not trained in PHP, so I don't understand some basic rules that are not commonly used. I hope you will be grateful for your guidance.

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Manual cloud:

Variable functions
PHP supports the concept of variable functions. This means that if a variable name has parentheses, PHP will look for a function with the same name as the value of the variable and will try to execute it.

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$ This-> $ runCode ();
This must be in your class.
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Class ModuleObject extends MasterObject
Go to his parent class and public class to search
Go to the configuration file config. php (usually called this) and check the introduced class file.
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$ RunCode = Load: moduleCode ($ this );
$ This-> $ runCode ();
Does the $ runCode in the second line have a relationship with the $ runCode in the first line?