Does code imported with require or include stay indefinitely?

[DWilliams]

Let's say I had a program that was going to interpret a user's text input.

 

If I wanted to make it modular and extensible I could just have a "commands" directory with one file containing php code for each command.

 

If in my main script I had a while loop running indefinitely that would loop once for every user input and process it, could I do something like the following?

 

while(!$shutdown)
{
   if(isset($command)
      require_once("commands/$command.php");
}

 

 

In theory, if $command gets set to something like 'sayhi', the script would import sayhi.php and execute the code in that file (code is just for demonstrating the idea, I know it has security problems).

 

Now, what happens the next time the loop loops? Will it clean up after itself and properly get rid of the last commands variables/statements and be ready for the next one or will things go bad quickly?

 

Would it be better to read the file into a variable and eval() it, or better yet read every command's code into an array at program start to save disk access time?

[Alex]

or better yet read every command's code into an array at program start to save disk access time?

This. Otherwise every time you entered the command it would have to re-include the file, this isn't necessary.

[Mchl]

Put your commands in functions and just call them when needed.