use of curly braces with string interpolation.

[Jochem Maas <jochem@xxxxxxxxxxxxx>]

hi guys,

[[
I original posted this to php-internals because I figured that 
php-general would not know the answer _ it had to do with intended use 
of functionality (I couldn't find anything on the web about) and I 
figured that the guys who wrote/write php would be best equipped to 
answer. well no joy - the post was gloriously ignored, so I figured I 
give it a shot here...
]]

I always use curly braces around vars placed in double quoted strings, I 
do this for 2 reasons:

1. I believe It helps the engine because the var delimitation is 
explicit, and this means the interpolation is (should be?) faster.
2. it looks nice (easier to read!)

I have tried to test this with a simple script that does a million 
interations - but I cannot get it to return consistent results - one 
time with curlies is faster, another its slower. the (php5) script I 
used to test is included at the bottom of the email for those who are 
curious. (I haven't been able to find relevant info on either google or 
php.net - are there any other search engines? ;-)

I am interested in knowing whether my first assumption regarding speed 
of interpolation is (in theory) at all correct.

If any of the php gurus would give advice as to use of curly braces in 
interpolated strings would it be:

a, always use them (its faster/better)
b, only when absolutely necessary
c, go away troll and figure it out for yourself
    (this one is tempting, n'est pas ;-)
d, something I haven't had the presence of mind to think of!

[[
choice c, is only relevant to internal btw :-)
]]

kind regards,
Jochem.

<?

class Tester
{
    public $testvar;
}

$t = new Tester;
$t->testvar = 'superduper';
$a = array('junk' => 'notbad!');

var_dump($t, $a);

$strs = array();

$start = mktime();
$i = 0;
do {
    $c = 'simplicity' + $i;
    $strs[] = "{$t->testvar} yadda yadda {$a['junk']} - {$c}\n";
    $i++;
} while ($i < 1000001);

$diff = (mktime() - $start);
echo  "With Curlies  - Total Time Taken ($diff): ".floor($diff / 60).' 
mins & '.($diff % 60).' secs'."\n";

$strs = array();

$start = mktime();
$i = 0;
do {
    $c = 'simplicity' + $i;
    $strs[] = "$t->testvar yadda yadda $a[junk] - $c\n";
    $i++;
} while ($i < 1000001);

$diff = (mktime() - $start);
echo  "Without Curlies - Total Time Taken ($diff): ".floor($diff / 60).' 
mins & '.($diff % 60).' secs'."\n";

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