Equivalent of upvar

[am_ggh@hotmail.com]

Is there a PHP equivalent of TCL's "upvar" ?

I will appreciate any insights.
Andy

[Oli Filth]

Re: Equivalent of upvar

am_ggh@hotmail. com wrote:[color=blue]
> Is there a PHP equivalent of TCL's "upvar" ?
>[/color]

Don't know TCL, but having found out what upvar is, I guess "global" is
the closest paradigm in PHP, see
http://www.php.net/manual/language.v...s.scope.global.

--
Oli

[Erwin Moller]

Re: Equivalent of upvar

am_ggh@hotmail. com wrote:
[color=blue]
> Is there a PHP equivalent of TCL's "upvar" ?
>
> I will appreciate any insights.
> Andy[/color]

Hi Andy,

upvar?
[if memory serves me well, TCL long time ago]
Isn't that a function to change variables in the environment of the CALLING
function?
------------------
$a = "hello";
something();
echo $a;

function something() {
// phantasycode
upvar ($a, "Joe");
}
------------------
That outputs Joe, right?
upvar IN function something() accesses variable $a in the
context/environment of the place where something() is called.
(That always confused the hell out of me.)

If that is what upvar does, I do not think there exists a PHP equivalent.
(That is: I never saw it)

But if you use objects, you can easily achieve the same functionality, I
expect.
Maybe using $_GLOBAL can also help for desired functionality.

Just my 2 cents...
(Me no expert on upvar. )

Regards,
Erwin Moller

[am_ggh@hotmail.com]

Re: Equivalent of upvar

Erwin

Thanks for replying. I appreciate your input.

Yes you are right, I have the need to set a value to the variable in
the calling environment (my case happens to be a function within a
function), In fact I need to possibly initialize variables (since they
might not even exist) in the calling function. $GLOBALS etc. lead to
unwanted side effects because of the nature of the task at hand*.

:(

Andy

P.S. *I realize this goes against the lean clean design theme, but the
task is one of conversion from one language to another :(

[Volker Hetzer]

Re: Equivalent of upvar

am_ggh@hotmail. com wrote:[color=blue]
> Erwin
>
> Thanks for replying. I appreciate your input.
>
> Yes you are right, I have the need to set a value to the variable in
> the calling environment (my case happens to be a function within a
> function), In fact I need to possibly initialize variables (since they
> might not even exist) in the calling function. $GLOBALS etc. lead to
> unwanted side effects because of the nature of the task at hand*.
>
> :(
>
> Andy
>
> P.S. *I realize this goes against the lean clean design theme, but the
> task is one of conversion from one language to another :([/color]
Well, maybe then you sould read a book about compiler construction?
As far as I learned, there's no requirement for reaching into the callers
frame. But I do admit, a certain swiss guys books make heavy use of that...

Lots of Greetings!
Volker

[am_ggh@hotmail.com]

Re: Equivalent of upvar

Volker

I have taken enough compiler construction courses, albeit a long time
ago. If you have recently read a book are all excited about your new
knowledge - I congratulate you. I know of at least 2 languages that do
support it, if the languages only simulate/use some trick at a higher
level, I'm absolutely fine with it.

Just so you know I am neither a fan of such practices, not propagating
it (practices like reaching out to the caller's space etc.). But I am
converting code from one language, where such a thing is heavily used,
which is where my question comes from.

Life is not always so cut and dry, there are always shades of grey in
between your black and someone's white :)

I want to thank you for writing, but I'm afraid your advice is
absolutely useless.

Andy.

P.S. Why you are even handling PHP related questions, when you have
nothing to contribute, is beyond me altogether, but I thank you for
your time.

[Volker Hetzer]

Re: Equivalent of upvar

am_ggh@hotmail. com wrote:[color=blue]
> Volker
>
> I have taken enough compiler construction courses, albeit a long time
> ago. If you have recently read a book are all excited about your new
> knowledge - I congratulate you.[/color]
I studied it.

[color=blue]
> P.S. Why you are even handling PHP related questions, when you have
> nothing to contribute, is beyond me altogether[/color]
Because call stacks are not an exlusive PHP issue. My contribution
was to help you avoid the issue.

[color=blue]
> but I thank you for your time.[/color]
Whatever.

Volker

[Oli Filth]

Re: Equivalent of upvar

am_ggh@hotmail. com said the following on 15/09/2005 17:48:[color=blue]
> Erwin
>
> Thanks for replying. I appreciate your input.
>
> Yes you are right, I have the need to set a value to the variable in
> the calling environment (my case happens to be a function within a
> function), In fact I need to possibly initialize variables (since they
> might not even exist) in the calling function. $GLOBALS etc. lead to
> unwanted side effects because of the nature of the task at hand*.
>[/color]

Would passing a variable by reference do what you want?

e.g.

function foo()
{
$a = 5;
bar($a);
// now $a == 8
}

function bar(&$var)
{
// $var is a reference to $a in the callee...
$var = 8;
}

--
Oli