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Date: Thu, 8 Feb 2007 20:32:38 +0300
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Subject: Suggestion: global variables being accessed in local scope
From: guilhermeblanco@hotmail.com (Guilherme Blanco)

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Hello PHP maintainers,During this week, I spoke with Sara Golemon about the=
 possibility to change one current behavior of PHP.My first suggestion, as =
you can see in my blog post: http://blog.bisna.com/archives/32#comments was=
 a new function called register_superglobal.While talking with her, I found=
 that it'll be easier to be implemented another thing.Currently, when we de=
al with objects and functions in a PHP application, to access most common v=
ariables, we have to do one of these things:function m() {    global $DB; /=
/ ...}Another one:function m() {    $DB =3D Database::getInstance();  // ..=
.}Or:function m() {    $DB =3D Registry::get("DB");  // ...}And finally... =
via Factory:function m() {    $DB =3D Env::getDatabaseConnection();  // ...=
}We can also specify via runkit a superglobal variable (DB), and use it.Whi=
le all those solutions have some costs, maybe there is a possibility to cha=
nge the structure and simplify all those lines of code.As I already said, m=
y first idea was a function, register_superglobal, which you register it an=
d access it in a local scope without using none of the examples I listed.Sa=
ra told me about superglobals and etc, but I suggested her about the possib=
ility to change the idea a little. Here is the comment I describe 2 possibl=
e ideas:"The perfect behavior should be (inside a function), if a variable=
=0A=
does not exist, try to access a global (without doing via $GLOBALS or=0A=
global). If it doesn=92t exist in the second try, then throw a fatal=0A=
error. With this, you do not need to think in superglobal variable or=0A=
anything else. Maybe this suggestion is currently too much difficult to ach=
ieve.=0A=
The workaround can be done using normal variables. But, as I=0A=
mentioned before, when the statement uses a variable, it checks for the=0A=
local variables declarations hash table; the idea is different here=85 if=
=0A=
the variable does not exist in local, look in the hash table I=0A=
mentioned (which stores the subscribed variables to behavior like=0A=
superglobal) and, if found, grab the variable from the global variable=0A=
declarations hash table.=0A=
As you can see, there will be only one performance impact (in normal=0A=
variable), doing a hash table checking. You do not need to change=0A=
autoglobal or static variables. In an average system, the needed time=0A=
to do this checking will be an advantage than the currently best=0A=
approach (Registry). You lose in one side, but receive more in the=0A=
other."She agreed with my idea ("That=92s all doable, and with autoglobals =
being CVs now, it=92s even doable=0A=
without too much performance impact on the global fetches themselves=85"), =
BUT she said I will have to convince engine team to accept this idea too. A=
lso, she said that will be a too much added complexity for too little. I di=
sagree with her, since currently there are much more processment retrieving=
 one object from a Registry or using a global accessor than another compile=
r hash checking. The performance impact is almost irrelevant (cannot be mea=
sured) and the final solution is cleaner than all the others. If you look a=
t real world large applications, you can experience these workarounds. And,=
 as I checked with my contact list (around 600), it'll be a great improveme=
nt of PHP.Now I am leaving this suggestion to internals list, and I hope yo=
u look affectionately at it.Best regards,Guilherme Blanco - Web Developer=
=0A=
CBC - Certified Bindows Consultant=0A=
Cell Phone: +55 (16) 9166-6902=0A=
URL: http://blog.bisna.com=0A=
MSN: guilhermeblanco@hotmail.com=0A=
S=E3o Carlos - SP/Brazil
_________________________________________________________________
O Windows Live Spaces est=E1 aqui! Descubra como =E9 f=E1cil criar seu espa=
=E7o na Web e sua rede amigos.
http://spaces.live.com/signup.aspx=

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