Thread

Throughout CodeIgniter’s code is the use of concatenation.

A simple example:

include_once(APPPATH.'controllers/'.$class.'.php');

With PHP, using concatenation for $variables is a convention rather than a rule. PHP has another way to incorporate the value of a variable into a string… parsing.

The same code can be written as this:

include_once(APPPATH."controllers/{$class}.php");

Now, you might think that parsing would actually take longer to execute, but it turns out that it’s faster than concatenation and has the nice side effect of being easier to read in most cases.

Note: the performance improvement may be negligible in most cases, but every little bit helps when thousands of concatenations may be done for each request to the framework.

You can even call object methods within a parsed string:

$str = "My name is {$me->getName()}."

I would personally like to see the CI developers adopt the parsing approach.

I’d think that something like this would only be beneficial if you had a super huge high traffic website. It would be interesting if you did some benchmarking and showed some numbers to us.

Interpolation is about 40% slower than Concatenation. Do some research.

http://www.google.com/?q=php+concatenation+vs+interpolation

Here is an interesting article on the subject:

http://nikic.github.com/2012/01/09/Disproving-the-Single-Quotes-Performance-Myth

But as the article says, the whole conversation is extremely pointless.

@Phil Sturgeon,
While the article you linked to, might suggest that parsing large double quoted strings may be no worse or even better than concatenating many separate variables, it needs to be stressed that double quoting purely text strings, without embedded variables, will create an unnecessary performance hit that should be avoided. And even if the performance hit is negligible it is better that a developer is aware of the facts and able to make an informed decision about such things themselves.

Absolutely. If there is only going to be a string and nothing else, then singles are a bazillionth quicker than doubles. If you are then adding variables to the string then singles are quicker for one variable, and doubles are quicker when handling more - at least that’s what this article suggests. It’s an old wives tale that “singles are always quicker than doubles”, which has been floating around the PHP community for a while.