call function defined in a file include after this file

Suppose I have following files

<?php 
     include 'file_A';
     include 'file_B';
 ?>

a function defined foo() in file_B, is there any way to use it in file_A by any means???

actually, I am working in a application where a开发者_如何转开发 range of different functions are defined in modules, I want to use these function across the modules without looking where it defined included before or after the file even.

As PHP is an interpreted language, you cannot do this.

What I would do as a solution is extract the methods you need to share into a CommonMethods class or something similar. Make them static if possible.

Then include the CommonMethods file before file_A and file_B.

I'd spend a little time researching design patterns for PHP before continuing your project. Spaghetti code is never a good thing.