From:	Jim Lucas	Date:	Thu May  8 18:23:03 2008
Subject:	Re: Recursion... Sort of...

Nathan Nobbe wrote:
> On Thu, May 8, 2008 at 3:48 PM, Matt Neimeyer <matt@neimeyer.org> wrote:
> 
>> Is there a way to tell if a function has been called that has resulted
>> in a call to the same function?
>>
>> We have an in-house CRM app that has a function that draws a tabbed
>> panel on a screen... BUT if there are sub-sub-tabbed panels we want to
>> invert the tab colors and panel colors...
>>
>> So...
>>
>> DrawSubTab($Set) - Black on White
>>   Content
>>   DrawSubTab($Set) - White on Black
>>      Content
>>      DrawSubTab($Set) - Black on White
>>         Content
>>      DrawSubTab($Set) - Black on White
>>         Content
>>         Etc...
>>
>> I suppose I could rewrite EVERY call to the function with a recursion
>> count like DrawSubTab($Set,$DepthCount+1) but that would be a MASSIVE
>> commit... whereas if the function can determine itself... All that
>> said I can't think of a good way to do it without a bastardized global
>> variable that track "how deep" we are and there is something that
>> bothers me about that approach... Unless that really is the easiest
>> way.
> 
> 
> you dont need a global, you can have a variable that persists throughout the
> request local only to the function itself using the static keyword.
> 
> function doStuff() {
>   static $callCount;
> 
>   if(!isset($callCount))
>    $callCount = 1;
>   else
>     $callCount++;
> 
>   /// do stuff w/ $callCount to potentially handle sub-tabs and stuff
> 
>   $callCount--;
> }
> 
> -nathan
> 

Look at the way he wants it to work.  Your way would change alternate the color 
each time the function is called.  I think the best/easiest way to keep track of 
depth will be by passing a variable in the function call itself.

-- 
Jim Lucas

    "Some men are born to greatness, some achieve greatness,
        and some have greatness thrust upon them."

Twelfth Night, Act II, Scene V
     by William Shakespeare