Variable scope - function in function

[Paul Lautman]

Here's something that I can't manage to find explicitly documented. In the
following snippet:

function outer() {
global $a;
function inner() {
global $a;
echo $a.'1<br>';
}
$a = 's';
inner();
echo $a.'2<br>';

}
outer();
?>

If either of the globals statements is removed, the variable is not
accessable within inner.

[Chung Leong]

Paul Lautman wrote:

Here's something that I can't manage to find explicitly documented. In the
following snippet:

function outer() {
global $a;
function inner() {
global $a;
echo $a.'1<br>';
}
$a = 's';
inner();
echo $a.'2<br>';

}
outer();
?>

If either of the globals statements is removed, the variable is not
accessable within inner.

What you're trying to do won't work if you call outer() more than once.
PHP has no support for closure or inner functions.

[Paul Lautman]

Chung Leong wrote:

Paul Lautman wrote:

Here's something that I can't manage to find explicitly documented.
In the following snippet:

function outer() {
global $a;
function inner() {
global $a;
echo $a.'1<br>';
}
$a = 's';
inner();
echo $a.'2<br>';

}
outer();

If either of the globals statements is removed, the variable is not
accessable within inner.

What you're trying to do won't work if you call outer() more than
once. PHP has no support for closure or inner functions.

Interesting, that case indeed fails. Yet I came across this problem when
defining a sort function for usort. In that case, one call call the sort
function more than once.

[Rik]

Chung Leong wrote:

Paul Lautman wrote:

Here's something that I can't manage to find explicitly documented.
In the following snippet:

function outer() {
global $a;
function inner() {
global $a;
echo $a.'1<br>';
}
$a = 's';
inner();
echo $a.'2<br>';

}
outer();

If either of the globals statements is removed, the variable is not
accessable within inner.

Which is abolutely logical.
What you're trying to do won't work if you call outer() more than
once.
PHP has no support for closure or inner functions.

You could circumvent this by:
if(!function_exists('inner'){
//define function
}

I'm very curious though why one would need such an imho messy function
declaration.

Grtz,
--
Rik Wasmus

[Mladen Gogala]

On Sun, 21 May 2006 21:41:27 +0100, Paul Lautman wrote:

Chung Leong wrote:

Paul Lautman wrote:

Here's something that I can't manage to find explicitly documented.
In the following snippet:

function outer() {
global $a;
function inner() {
global $a;
echo $a.'1<br>';
}
$a = 's';
inner();
echo $a.'2<br>';

}
outer();
If either of the globals statements is removed, the variable is not
accessable within inner.

What you're trying to do won't work if you call outer() more than
once. PHP has no support for closure or inner functions.

Interesting, that case indeed fails. Yet I came across this problem when
defining a sort function for usort. In that case, one call call the sort
function more than once.

Well, it fails complaining about the duplicate declaration, not about the
invocation. This version will work:

#!/usr/local/bin/php
<?php
$a="A";
function outer() {
global $a;
if ($a=="A") {
function inner() {
global $a;
echo $a."1\n";
}
}
$a = "s";
inner();
echo $a."2\n";

}
outer();
outer();
?>
$

This way, the inner function is not re-declared during the second
invocation. This can also be simulated by using eval.
--
http://www.mgogala.com

[Paul Lautman]

Rik wrote:

Chung Leong wrote:

Paul Lautman wrote:

Here's something that I can't manage to find explicitly documented.
In the following snippet:

function outer() {
global $a;
function inner() {
global $a;
echo $a.'1<br>';
}
$a = 's';
inner();
echo $a.'2<br>';

}
outer();
If either of the globals statements is removed, the variable is not
accessable within inner.

Which is abolutely logical.

What you're trying to do won't work if you call outer() more than
once.
PHP has no support for closure or inner functions.

You could circumvent this by:
if(!function_exists('inner'){
//define function
}

I'm very curious though why one would need such an imho messy function
declaration.

Grtz,

I don't actually need it. What happened was that I was having trouble
getting a variable to be global so that I could use a single callback
function for my usort and have it sort on different "fields" in my array. It
worked OK in a test setup, but not in the application. Turns out that I
hadn't realised that in the application, the callback function was declared
inside another function, whereas in the test setup it was at the top level.

[Rik]

Paul Lautman wrote:

What you're trying to do won't work if you call outer() more than
once.
PHP has no support for closure or inner functions.

You could circumvent this by:
if(!function_exists('inner'){
//define function
}

I'm very curious though why one would need such an imho messy
function declaration.

Grtz,

I don't actually need it. What happened was that I was having trouble
getting a variable to be global so that I could use a single callback
function for my usort and have it sort on different "fields" in my
array. It worked OK in a test setup, but not in the application.
Turns out that I hadn't realised that in the application, the
callback function was declared inside another function, whereas in
the test setup it was at the top level.

Check, while nesting more and more it becomes hard to find errors like that.
I always try to keep "home-made" funstions in a seperate include for that
reason.

Grtz,
--
Rik Wasmus