This blog post is not for the faint-hearted! Some people will strongly disagree with me and some others will probably want to kill me at the upcoming Zend Conference. And if starting an argument in the comments can help you feel better, please feel free to do so. If you want to have a more advanced
discussion on this topic, vote for my talk at the Zend UnConference.
So, you think PHP is a templating engine? So did I... for a very long time. But recently, I changed my mind. Even if PHP can be used as a templating engine, the syntax is just plain ugly as a template language.
For several years now, I have been promoting web development best practices, and one of them is the separation of concerns. Of course, as the lead developer of symfony, all the projects we work on at Sensio are modeled after the MVC architecture. It certainly helps when we have big projects where many people need to work together. The
developers work on the code (the Controllers and the Model) and the web designers work on the design. And templates are sometimes written by developers, but more often than not, they need to be written by web designers or by the webmasters themselves.
And a template language is something that helps you to write templates that respects this separation of concerns. A template language should find a good balance between giving enough features to ease implementing the presentation logic, and restricting the advanced features to avoid the business logic to cripple your
templates.
So, when I asked a few days ago about the best and popular templating engines in PHP on Twitter, some people naturally answered "PHP" itself. I was not even surprised as that would probably have been my answer some weeks ago too.
Why PHP is not (anymore) a good template language?
Why do people still think PHP is a templating engine? Sure enough, PHP started its life as a template language, but it did not evolve like one in the recent years. If you think PHP is still a template language, can you give me just one recent change in the PHP language which enhanced PHP as a template language? I cannot think of one.
Template languages evolved a lot since 1995 and the initial release of PHP/FI:
<!--include /text/header.html-->
<!--getenv HTTP_USER_AGENT-->
<!--ifsubstr $exec_result Mozilla-->
Hey, you are using Netscape!<p>
<!--endif-->
<!--sql database select * from table where user='$username'-->
<!--ifless $numentries 1-->
Sorry, that record does not exist<p>
<!--endif exit-->
Welcome <!--$user-->!<p>
You have <!--$index:0--> credits left in your account.<p>
<!--include /text/footer.html-->
And as a matter of fact, PHP doesn't support many features modern template languages should have nowadays.
I will take Django as an example of a modern template language in my examples for reasons you will understand later on, and mainly because I think Django template language hits that sweet spot I talked about above.
The following sections describes the main features I want to find in a modern template language:
Concision
The PHP language is verbose. You need no less than 14 characters just to output a simple variable (and no, using the more compact <?= shortcut is not an option):
<?php echo $var ?>
And PHP becomes ridiculously verbose when it comes to output escaping (and yes, escaping variables coming from an unsafe source is mandatory nowadays):
<?php echo htmlspecialchars($var, ENT_QUOTES, 'UTF-8') ?>
Compare with the same examples written with the Django template language:
{{ var }}
{{ var|escape }}
Template oriented syntax
This one is mostly a matter of taste, but modern template language have nice idioms to express common needs. For instance, let's say you want to iterate over an array and want to display a default text when the array is empty. That's very common, but the PHP version is not very readable:
Truncated by Planet PHP, read more at the original (another 19059 bytes)
