Re: [PHP-DEV] Calling symbol table patch From: Andi Gutmans (andi <email protected>)
Date: 11/20/00

At 09:44 PM 11/20/00 +0100, Sterling Hughes wrote:
>At 10:43 PM 11/20/2000 +0200, Zeev Suraski wrote:
>>At 22:35 20/11/2000, Andrei Zmievski wrote:
>>>On Mon, 20 Nov 2000, Andi Gutmans wrote:
>>> > Andrei,
>>> >
>>> > The patch slows down the main function call opcode. I really don't
>>> like that.
>>>
>>>How much really does it slow it down? It's just putting a pointer on a
>>>stack before the actual call and taking it off afterwards.
>>
>>Well, a stack push is a considerable slowdown. How much it slows things
>>down exactly obviously depends on your script...
>>
>>> > Is it really that important? When did you bump into this need and why
>>> > couldn't you handle it with the existing functionality? I'm not quite
>>> clear
>>> > as to when in programming you *need* such functionality and can't
>>> write the
>>> > code in a different (IMO better) way.
>>> > But then again, you might have a very good reason because I don't know
>>> > when/how this need arose.
>>>
>>>It's impossible to implement some functionality without some sort of a
>>>patch like this. For example, I am working on a template engine, and I
>>>need to assign a variable to the template, and I got sick of typing
>>>something like this:
>>>
>>>$tpl->assign('foo', $foo);
>>>
>>>So, I wanted to speed it up and have a method that could take just names
>>>of the variables and assign them using their current values in the
>>>calling scope, like this:
>>>
>>>$tpl->batch_assign('foo', 'bar', 'color1');
>>>
>>>But there is no way to get to calling scope:
>>>
>>>class Template {
>>> function batch_assign() {
>>> $args = func_get_args();
>>> foreach ($args as $var_name) {
>>> /* Right here, we have no idea what $$var_name
>>> is in the
>>> * function that called us. */
>>> }
>>> }
>>>}
>>>
>>>So, that's why I wanted that patch.
>>
>>I think that the Right Way to do it would actually be a function that
>>returns the current symbol table. Such a function can be implemented
>>without slowing down or modifying anything in the engine, and then you
>>could write:
>>
>>$tpl->batch_assign('foo', 'bar', 'color1', get_active_symtable())
>
>
>>It's a bit more to type, no doubt, but I think it's more correct that
>>way... Perhaps one day we'll have macros in PHP :)
>
>
>Uhh, you guys turned down a patch that did just that, it was a preliminary
>version of the get_defined_vars() function which returns the global
>symbol table and the current symbol table. I had it so that you could
>then access and modify the variables returned (since it was merely a
>reference to the respective symbol tables), but (Andi I believe) requested
>that I not do this, so as it is it just returns the names of the different
>variables and not their contents.

Hmm I thought it did so :) I was against making it modifiable but it's OK
to create a copy and it would solve Andrei's problem. zval_copy_ctor()
would do.

Andi 

---
Andi Gutmans <andi <email protected>>
http://www.zend.com/

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