Hi, I have a few ideas for enhancements to PHP's functions that would make them much more powerful.  

First, when using variable length argument lists (using func_get_arg, etc.) there should be a way to treat these as references.  As of now, it seems to me that only pass by value can be achieved with this mechanism.  A simple func_set_arg function would fill this gap nicely.

Second, macros would be a nice addition.

Third, and most important I believe, there needs to be a mechanism for inheriting scope in a function - rather than choosing between the extremes of global and local.  For instance, the following code demonstrates my point:

function a() {
   global $var;
   $var = 10;
}

function b() {
   $var = 5;
   a();
   print $var; # still prints 5 because a()'s $var is global
               # whereas b()'s var is local.  There is NO
               # way to reference b()'s var in a() as it
               # stands - the only way to do it would be to
               # make a() get passed a reference to $var
}

$var = 5;
a();
print $var; # here, however, everything works fine because
            # the $var here is global

The behavior of a() here is, if not downright inconsistent, somewhat frustrating.  Now, consider if we had an inherit construct, which inherited the variable from the calling scope.  If a() then was defined as

function a() {
   inherit $a;
   $a = 10;
}

the behavior would be more consistent to what the writer of function b() intended.

With these additions, I think a lot more could be accomplished with functions.

Thanks for a great product,
Robby Walker
CD-Lab
www.cd-lab.com