Posted by Janwillem Borleffs on 10/21/34 11:23

Andreas Thiele wrote:
>> The eval is useless here.
>> ...
>
> No, it creates local variables. These were meant to be used in some
> complex processing directly following, something like
>
> if ($foo == 3)
> if (some_func($bar) == 4 && $baz ==2) ... // I mean a lot of
> conditions or other uses following.
>

I don't see what's the benefit of using:

eval(abind("arr", array("foo", "bar", "baz")));

instead of using:

abind("arr", array("foo", "bar", "baz"));

Besides, in most cases you can use call_user_func or call_user_func_array to
accomplish what you want to do instead of using eval for this.

> I didn't expect this. Are you sure? I mean php is an interpreter, or
> does it compile things? If it is a pure interpreter, I would expect
> the parser itself using eval a lot. So why should this be especially
> expensive? Do you have any hints on something I might read regarding
> this?
>

When you use eval in your code, it must be evaluated before the engine can
continue the processing of your script. One of the side-effects is that it's
much slower as the following test will show:

<?php
$start = array_sum(explode(' ', microtime()));

for ($i = 0; $i < 100; $i++) {
eval('$foo = "bar";');
}

$end = array_sum(explode(' ', microtime())) - $start;
echo 'Finished in ', round($end, 5), " seconds\n";

$start = array_sum(explode(' ', microtime()));

for ($i = 0; $i < 100; $i++) {
$foo = "bar";
}

$end = array_sum(explode(' ', microtime())) - $start;
echo 'Finished in ', round($end, 5), " seconds\n";

?>


JW

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