Re: Execution order of PHP

Sándor Tamás <sandortamas@xxxxxxxxxxx> · Wed, 10 Mar 2010 15:20:02 +0100

2010.03.10. 14:41 keltezéssel, Bob McConnell írta:
From: Auke van Slooten

In a hobby project I'm relying on the order in which the following

piece

of PHP code is executed:

$client->system->multiCall(
    $client->methodOne(),
    $client->methodTwo()
);

Currently PHP always resolves $client->system (and executes the __get

on

$client) before resolving the arguments to the multiCall() method

call.

Is this order something that is specified by PHP and so can be relied
upon to stay the same in the future or is it just how it currently

works.

If it cannot be relied upon to stay this way, I will have to rewrite

the

multiCall method and API...

Think about it from the parser's point of view. It has to evaluate
$client->system to determine the parameter list for multiCall(). Then it
has to evaluate those parameters before it can stuff their values into
the stack so it can call the function. But, whether it evaluates the
parameter list left-to-right or vice versa is implementation dependent.
I don't believe you can rely on it always being the same unless you
always use the same interpreter.

Bob McConnell

I think it cannot be that the evaluation order of the parameters is 
implementation dependent.
Just think about it:
  $someobject->method($a++, $a++);

What will be the result? Or there has to be some directive to tell the 
parser to evaluate the parameters from left to right or vice versa.
And if there isn't, in some future release, there has to be.

SanTa

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