Nesting functions within a class?

knickerlas

Hi
I've been trying to nest a function in a class but I get 'call to undefined function'
If I cut the nested function out it works fine?

I know the simple answer is to stick with two seperate functions but why won't it behave as it should?

Cheers

Nick

Anon

Are you saying you have something like:

class X {

function Y() {
function Z() {
}
}

}

???

And where do you get the error? When you try to call the function?

-- Rich Rijnders
-- Irvine, CA US

knickerlas

Thats exactly it on all counts.
Any ideas?

Nick

Anon

Puting functions within a class should not be a problem (they are usually referred to as methods of the class). Depending on your version of PHP, nesting functions within functions should also not be a problem; php usually treats them as distinct functions. Things may get dicy when you start nesting functions within functions within a class, though...

My suspicion is that your problem has more to do with where and how you are invoking the function. Let's go back to the example I gave before:

==================
class X {

function Y () {
function Z () {
}
}

}

If you are somewhere in a script and want to execute a method within the class:

$var1 = new X(); // create the object
$var2 = $var1->Y(); // invoke method Y of the object
$var3 = $var1->Z(); // invoke method Z of the object

If, however; you are inside method Y (or any other method inside class X) and you want to invoke function Z, you must do so with the "this->" directive:

$classprop1 = $this->Z(); // invoke method Z

Another important note is that if you are using php3, then your functions must appear in the code prior to any line of code that invokes the function. In php4, this is not a requirement.

Let me know if any of this helps or if your problem is elsewhere.

-- Rich Rijnders
-- Irvine, CA US

knickerlas

Okay, here it is!
The code below produces the errror (call to undefined function reindex())
but if I cut 'n' paste reindex out of delete_page() then it works fine.
Bizzarre.

Thanks for your help

Nick

}

Anon

Yeah, I see what you mean...

Some quick test scripts tell me that the problem is only when nesting functions within a class definition. None of the docs i've seen mention a nesting restriction within classes, but it is apparently there.

It appears that the inside function is only defined within PHP if the outside function is evoked. I evoked the outside function in a test script prior to evoking the inside function and it ran fine!

It makes sense from the compiler's perspective. My guess is that this is a side effect of functionality that allows scripts to create new scripts/functions on the fly.

I can see where this can enable us emulate things like function overloading. You can create multiple functions with the same name, but nested inside different function "containers". Depending on what your script needs to do, you can evoke a different container that has the version of the function you want. Later, your script only needs to evoke the "inside" function name, and the correct one will run!

Coooooool...

I will have to experiment to see if the function can be redifined within PHP if I execute the different outside functions at different times...

But I guess we will have to be more careful when includ()ing or require()ing shared function within our class definitions.

-- Rich Rijnders
-- Irvine, CA US

kparker

It would surprise me if PHP supported nested function definitions in any intentional way; the underpinnings are so C-like. But surely you don't have
to make reindex() global to make this work--it should be enough if they
are sibling functions within the class definition.

knickerlas

Mornin'
Thanks for all your help Richard, it is odd but certainly not the end of the world so I guess I'll just have them as related functions within the class.

Cheers

Nick