From:	David Otton	Date:	Thu May  8 18:28:08 2008
Subject:	Re: Recursion... Sort of...

2008/5/8 Matt Neimeyer <matt@neimeyer.org>:

> Is there a way to tell if a function has been called that has resulted
> in a call to the same function?

debug_backtrace()

Can't comment on performance, though. Its an inelegant solution.

> 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...

Nested? You may be able to do this in pure CSS, without keeping a
depth counter at all.

> 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

It's an easy change.

function DrawSubTable($Set, $DepthCount = 0)
{
    [..]
    DrawSubTable($Set, $DepthCount + 1);
    [..]
}

By providing a default value, all the calls to DrawSubTable() can
remain unchanged. You just have to modify its own calls to itself.