Q:

How can I get a PHP script **results** included into another PHP script?

I'd like to include the results of a given script (let's say a.php) into another script (let's say b.php). 
Although there is the PHP include statement and their other counterparts (include_once, require and require_once), it seems all of them include the file contents instead of its processing results as I would expect.
So how can I get a.php processed first and then include its results (not the file contents itself) into b.php script ?
On the other hand, if my included file (a.php) has a return statement, is the entire file expected to be processed first or its contents are also included into b.php as is ?
Thanks in advance for your replies.

A:

a.php:
<?php
echo "world";

b.php:
<?php
ob_start();
include("a.php");
$a= ob_get_clean();
echo "Hello, $a!";  

perhaps?

