how to make all variables global inside a function

sfullman

Hi There,

I am developing a site development site - i.e. create your own website similar to Godaddy's website tonight.

I have decided against object oriented programming to keep things simple (please no lectures, that's not what I'm asking about 🙂

But, the "array" that describes the nested block structure of a HTML page (i.e. divs inside of divs) can only be sensibly processed by a recursive function.

That means that arrays and variables I depend on using outside the function are no longer visible.

So the question is, how can I have the convenience of a recursive function but have the function make itself permeable to all variables as if it was not there? Safely.

And without having to declare global $this, global $that, global $whatever - another housekeeping task to keep up with.

Thanks, and I am hoping also this method doesn't slow the process down significantly. I appreciate your experience - know someone else out there has dealt with this. Thanks!

Sam

dagon

unclear to me what you want, my first thought however is "template engine".

bradgrafelman

sfullman;10993131 wrote:
That means that arrays and variables I depend on using outside the function are no longer visible.

Why aren't they? Why can't you just pass them in as parameters?

If you really want to write obfuscated, messy code (hey, you shot down OOP, so why not shoot down other sensible concepts? 😉), then why encapsulate the processing code inside of a function at all?

sfullman;10993131 wrote:
So the question is, how can I have the convenience of a recursive function but have the function make itself permeable to all variables as if it was not there?

Well, one neat and clean solution would be an OOP approach (I don't consider offering the best advice a "lecture", so I assume your third paragraph above doesn't apply?).

Next, you could simply pass whatever variables you need into the function as parameters (by reference, if you want to alter those variables' values as well).

Finally, if all else fails, you could just (ab)use the $GLOBALS superglobal array, though at that point I say you might as well go with my suggestion above (which I wasn't seriously suggesting at all, mind you!) and just get rid of the function encapsulation altogether.

sfullman;10993131 wrote:
And without having to declare global $this, global $that, global $whatever - another housekeeping task to keep up with.

And not to mention the fact that if those global variables ever change names or are re-used elsewhere, your function's dependency on them won't be very apparent and you risk breaking it without ever having even touched it. But then again, that's what function parameters (or OOP!) are for.

NogDog

Just a guess after a quick skim of this thread, but it sounds like you may want to pass that variable by reference into the function in question, so that any modifications made to it within the function will affect it in the global scope as well.

sfullman

however, I don't want to pass variables by reference etc. etc. - the issue is I already had a great set of coding which reads variables from various locations and which are well policed against hacking (I am a php heretic and have globals turned on, gasp)

I want to take some great code which it turns out must live inside a recursive function and not have to think about passing variables, or setting what variables are available. here is what I would do short of some "smarter" idea from you guys (who have great ideas indeed):

function seerightthroughme(){
   $skip=array('HTTP_POST_VARS', '_POST', /* etc. etc. - no need to do this because they are already globally available */ );
   foreach($GLOBALS as $n=>$v){
      if(in_array($n,$skip))continue;
      eval('global $'.$n.';');
   }
   //do something recursive.. :)
   #whatever

   //now this will behave as it always had
   require('the_the_great_file_I_already_had_developed.php');

}

Weedpacket

sfullman wrote:
(I am a php heretic and have globals turned on, gasp)

In that case, whatever you do, don't upgrade to PHP 5.4 or later.

bradgrafelman

Weedpacket;10993304 wrote:
In that case, whatever you do, don't upgrade to PHP 5.4 or later.

I was going to suggest just the opposite - upgrade right away and start learning how to write PHP code properly. :p

NogDog

I suppose if you don't have the time/inclination to move your PHP code-base into the 21st century, you could use [man]import_request_variables/man and perhaps also [man]extract/man.

sfullman

FYI I have php 5.2.14 running and will probably not upgrade until php 6 (?) comes out.

I appreciate the feedback and love you guys to pieces but recall that sometime there is not a cost benefit to totally redoing something. What I was hoping to find out was if there was a way to make globals available inside of a function. Two ways came to mind, one that I posted above and then the other one as nogdog suggested simply:

extract($GLOBALS); //inside function

but I thought therre might be a more elegant declaration built into php.

Thanks

NogDog

There is probably no "elegant" solution, since the use of globals within a function tightly couples it to the calling code, largely defeating one of the purposes of using functions in the first place (and often leading to debugging headaches down the road).

Weedpacket

sfullman wrote:
probably not upgrade until php 6 (?) comes out.

Weedpacket wrote:
don't upgrade to PHP 5.4 or later.

but I thought therre might be a more elegant declaration built into php.

Globals in PHP are intrinsically inelegant by design.

sfullman

when I was going to college, remember vaguely something where you would write code "if condition then goto line 4829 whatever" - I'm really a greenhorn when it comes to languages like Basic and Cobol and etc. - but that part of it always made sense, i.e. you could have a section of code that you could go back to. And, in effective it wasn't inside anything called a function in those days so there was no "black box" barrier as functions or even objects have. So even though that type of "goto" coding seems to have disappeared, the concept was inherently elegant BEFORE the function came along..

traq

oohh, you're in luck: goto: php.net

also note: goto: xkcd.com

Weedpacket

sfullman wrote:
So even though that type of "goto" coding seems to have disappeared...

Have you ever wondered why?

Edsger W. Dijkstra wrote:
The unbridled use of the go to statement has as an immediate consequence that it becomes terribly hard to find a meaningful set of coordinates in which to describe the process progress. ... The go to statement as it stands is just too primitive, it is too much an invitation to make a mess of one's program.

"Letters to the Editor: GO TO Statement Considered Harmful", Comm. ACM. 11 (3), March 1968

there was no "black box" barrier as functions or even objects have

You say that like it's a good thing, when it's your failure to "black-box" your system that now sees you being held hostage by it.

a LONG TIME AGO there was something like BASIC

And a LONG TIME AGO (and I'm only able to refer to 1975 as "a long time ago" with a straight face because it's in the context of programming language design) Dijkstra said "It is practically impossible to teach good programming to students that have had a prior exposure to BASIC: as potential programmers they are mentally mutilated beyond hope of regeneration. "