Variable scope mystery

[Maarten]

Here is a nice problem. I have two scripts, one calling the other with via
an include. The script that is included contains a variable, a function and
a call to that function. The variable needs to be accessible to the
function, so I declare it having a global scope. Then I execute the
function, which should echo the value of the variable. Contrary to what I
expected, the variable isn't there.

The code of the 2 programs is:

script1.php
<?php
function blah()
{
include("script 2.php");
}

blah();
?>

script2.php
<?php
$foo = "bar";

function blahblah()
{
global $foo;
echo $foo;
}

blahblah();
?>

I can't see anything wrong with the way I set this up, even more since a
call to script2.php does exactly what it's suppossed to do: echo the value.
What's going on here is beyond me. Anybody has a clue?

Kind regards, Maarten

[daemon]

Re: Variable scope mystery

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Maarten wrote:[color=blue]
> Here is a nice problem. I have two scripts, one calling the other with via
> an include. The script that is included contains a variable, a function and
> a call to that function. The variable needs to be accessible to the
> function, so I declare it having a global scope. Then I execute the
> function, which should echo the value of the variable. Contrary to what I
> expected, the variable isn't there.
>
> The code of the 2 programs is:
>
> script1.php
> <?php
> function blah()
> {
> include("script 2.php");
> }
>
> blah();
> ?>
>
> script2.php
> <?php
> $foo = "bar";
>
> function blahblah()
> {
> global $foo;
> echo $foo;
> }
>
> blahblah();
> ?>
>
> I can't see anything wrong with the way I set this up, even more since a
> call to script2.php does exactly what it's suppossed to do: echo the value.
> What's going on here is beyond me. Anybody has a clue?
>
> Kind regards, Maarten
>
>[/color]

I can... you can't expect to include another function within blah();

To do it, use a class, and include your blahblah(); and just use blah();
to reference to it within your class::function ();
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[Oli Filth]

Re: Variable scope mystery

daemon said the following on 18/11/2005 16:43:[color=blue]
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> Hash: SHA1
>
> Maarten wrote:
>[color=green]
>>Here is a nice problem. I have two scripts, one calling the other with via
>>an include. The script that is included contains a variable, a function and
>>a call to that function. The variable needs to be accessible to the
>>function, so I declare it having a global scope. Then I execute the
>>function, which should echo the value of the variable. Contrary to what I
>>expected, the variable isn't there.
>>
>>The code of the 2 programs is:
>>
>>script1.php
>><?php
>>function blah()
>>{
>> include("script 2.php");
>>}
>>
>>blah();
>>?>
>>
>>script2.php
>><?php
>>$foo = "bar";
>>
>>function blahblah()
>>{
>> global $foo;
>> echo $foo;
>>}
>>
>>blahblah();
>>?>
>>
>>I can't see anything wrong with the way I set this up, even more since a
>>call to script2.php does exactly what it's suppossed to do: echo the value.
>>What's going on here is beyond me. Anybody has a clue?
>>
>>Kind regards, Maarten
>>
>>[/color]
>
>
> I can... you can't expect to include another function within blah();[/color]

Yes you can.

The problem is that by declaring $foo = "bar" in what intuitively looks
like the global scope within script2.php, it's actually being declared
in the scope of blah(), and therefore isn't a global variable, and
therefore can't be accessed within blahblah().

Change script2.php to:

<?php
global $foo;
$foo = "bar";

function blahblah()
{
global $foo;
echo $foo;
}

blahblah();
?>



--
Oli

[Maarten]

Re: Variable scope mystery

Thank you for replying, but you are mistaking. This for example works fine,
even when the second function is included from an outside file.

function blah()
{
function blahblah()
{
echo "foo";
}
blahblah();
}
blah();



"daemon" <d43m0n@shaw.ca > wrote in message
news:cxnff.5236 97$oW2.516262@p d7tw1no...[color=blue]
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Maarten wrote:[color=green]
>> Here is a nice problem. I have two scripts, one calling the other with
>> via
>> an include. The script that is included contains a variable, a function
>> and
>> a call to that function. The variable needs to be accessible to the
>> function, so I declare it having a global scope. Then I execute the
>> function, which should echo the value of the variable. Contrary to what I
>> expected, the variable isn't there.
>>
>> The code of the 2 programs is:
>>
>> script1.php
>> <?php
>> function blah()
>> {
>> include("script 2.php");
>> }
>>
>> blah();
>> ?>
>>
>> script2.php
>> <?php
>> $foo = "bar";
>>
>> function blahblah()
>> {
>> global $foo;
>> echo $foo;
>> }
>>
>> blahblah();
>> ?>
>>
>> I can't see anything wrong with the way I set this up, even more since a
>> call to script2.php does exactly what it's suppossed to do: echo the
>> value.
>> What's going on here is beyond me. Anybody has a clue?
>>
>> Kind regards, Maarten
>>
>>[/color]
>
> I can... you can't expect to include another function within blah();
>
> To do it, use a class, and include your blahblah(); and just use blah();
> to reference to it within your class::function ();
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>
> iD8DBQFDfmZh/WE0aXnOUiYRAmpQ AJ4gbRQBepMOTri ilvr82GryQuykTQ Cgk0TZ
> tZ637ZaemoIUKhM 4n4Frh2w=
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[Maarten]

Re: Variable scope mystery

Yes, that's it! So, a variable declared inside a function isn't available
inside nested function even while you are calling it in (global). You'll
have to declare it global in the main function first. This can cause
problems though, as there might be a variable with the same name outside the
main function that you do not want to access. See what I mean? The solution
is obvious of course, but sometimes you just don't know what variables live
out there, do you?


"Oli Filth" <catch@olifilth .co.uk> wrote in message
news:YTnff.1224 2$fN5.7154@news fe6-gui.ntli.net...[color=blue]
> daemon said the following on 18/11/2005 16:43:[color=green]
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>
>> Maarten wrote:
>>[color=darkred]
>>>Here is a nice problem. I have two scripts, one calling the other with
>>>via an include. The script that is included contains a variable, a
>>>function and a call to that function. The variable needs to be accessible
>>>to the function, so I declare it having a global scope. Then I execute
>>>the function, which should echo the value of the variable. Contrary to
>>>what I expected, the variable isn't there.
>>>
>>>The code of the 2 programs is:
>>>
>>>script1.ph p
>>><?php
>>>function blah()
>>>{
>>> include("script 2.php");
>>>}
>>>
>>>blah();
>>>?>
>>>
>>>script2.ph p
>>><?php
>>>$foo = "bar";
>>>
>>>function blahblah()
>>>{
>>> global $foo;
>>> echo $foo;
>>>}
>>>
>>>blahblah() ;
>>>?>
>>>
>>>I can't see anything wrong with the way I set this up, even more since a
>>>call to script2.php does exactly what it's suppossed to do: echo the
>>>value. What's going on here is beyond me. Anybody has a clue?
>>>
>>>Kind regards, Maarten
>>>[/color]
>>
>>
>> I can... you can't expect to include another function within blah();[/color]
>
> Yes you can.
>
> The problem is that by declaring $foo = "bar" in what intuitively looks
> like the global scope within script2.php, it's actually being declared in
> the scope of blah(), and therefore isn't a global variable, and therefore
> can't be accessed within blahblah().
>
> Change script2.php to:
>
> <?php
> global $foo;
> $foo = "bar";
>
> function blahblah()
> {
> global $foo;
> echo $foo;
> }
>
> blahblah();
> ?>
>
>
>
> --
> Oli[/color]

[Oli Filth]

Re: Variable scope mystery

Maarten said the following on 18/11/2005 17:28:[color=blue]
> Yes, that's it! So, a variable declared inside a function isn't available
> inside nested function even while you are calling it in (global). You'll
> have to declare it global in the main function first. This can cause
> problems though, as there might be a variable with the same name outside the
> main function that you do not want to access. See what I mean? The solution
> is obvious of course, but sometimes you just don't know what variables live
> out there, do you?
>[/color]

I think the solution is: Don't use global variables!

Always explicitly pass required variables to functions.

--
Oli

[Maarten]

Re: Variable scope mystery

What can I say? You are right of course. Thanks you very much for your help.

Regards, Maarten

"Oli Filth" <catch@olifilth .co.uk> wrote in message
news:Lboff.1227 3$fN5.8401@news fe6-gui.ntli.net...[color=blue]
> Maarten said the following on 18/11/2005 17:28:[color=green]
>> Yes, that's it! So, a variable declared inside a function isn't available
>> inside nested function even while you are calling it in (global). You'll
>> have to declare it global in the main function first. This can cause
>> problems though, as there might be a variable with the same name outside
>> the main function that you do not want to access. See what I mean? The
>> solution is obvious of course, but sometimes you just don't know what
>> variables live out there, do you?
>>[/color]
>
> I think the solution is: Don't use global variables!
>
> Always explicitly pass required variables to functions.
>
> --
> Oli[/color]