ID: 33418
Updated by: [EMAIL PROTECTED]
Reported By: alex-spam at rdc dot ru
-Status: Open
+Status: Wont fix
Bug Type: Feature/Change Request
Operating System: all
PHP Version: 4.3.11
New Comment:
Yes, I get what you want... but it's impossible to implement. You can't
insert compiled code INTO the current scope - that's just not possible
with the Zend Engine. (and it would require way too much work to do
this.
Previous Comments:
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[2005-06-21 13:03:11] alex-spam at rdc dot ru
I'm not a PHP internals expert so I can't get into detail on how
'precompiled evals' can be implemented.
No matter how it's named or implemented, the desired functionality
would allow a programmer to:
- build a piece of code in CURRENT context and prepare it for execution
(compile, bind all variables, functions etc.)
- execute this code using a lightweight language construct
'Preparation' process may have limitations, e.g. all referenced
variables must already be created, etc. In this case eval_prepare()
might just return FALSE with an appropriate error message.
Creating anonymous functions or using eval() are great by themselves,
but not for optimization purposes. I hope you've got my idea.
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[2005-06-21 12:54:29] [EMAIL PROTECTED]
New OpArrays (like your eval thing returns) can only be executing by
calling a function (or something that resembles it very closely)... so
you're not gaining anything here.
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[2005-06-21 12:43:39] alex-spam at rdc dot ru
create_function() will create a _function_. When we're talking tough
optimization, every extra function call is an issue.
On 10k calls strcmp() is MUCH slower than '==' operator on strings.
Function calls are quite expensive in PHP. The context is switched and
caller's variables become invisible.
Precompiled eval()s would allow to unroll small loops without changing
the context, which is also important. What do you think?
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[2005-06-21 11:36:32] [EMAIL PROTECTED]
You could use create_function() to create your dynamic
code and execute the returned function. No need for a new
function.
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[2005-06-21 11:13:35] alex-spam at rdc dot ru
Description:
------------
From: Alex Fortuna
My proposal, if accepted and implemented, will allow for ever tougher
optimization of processing-intensive PHP scripts.
I think it would be great if, in addition to existing eval() function,
a pair of functions were implemented, like:
int eval_prepare (string $code);
bool eval_exec (int $handle);
eval_prepare() compiles a piece of code and stores it in engine's
memory under an integer handle. You call it once outside the processing
loop.
eval_exec() executes the given handle's code. You call it INSIDE the
processing loop.
The reason is practical: sometimes the programmer KNOWS how to optimize
a piece of code, but he CAN'T, since certain parts of it are dynamic.
For example, actual string token values may differ from call to call,
though processing logic is always the same.
The possibility to separately compile and execute script-generated PHP
code will give programmers a unique chance to achieve ever greater
script performance, the demand for which is continuosly growing.
I've made some prototype performance benchmarks on a script which
parses syntax. The results were amazing: about 2 to 3 times performance
increase without extra script complexity.
If you need a working example, please write via e-mail.
Thank you for your time.
Best regards,
Alex
Reproduce code:
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Expected result:
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Actual result:
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Edit this bug report at http://bugs.php.net/?id=33418&edit=1
