Comments

Introducing PHP Code Blocks and Comments

When working with PHP, it's essential to understand how to define sections of code that the PHP interpreter should execute. We achieve this by enclosing our PHP instructions within special tags. The opening tag, <?php, signals the beginning of the PHP code block, and the closing tag, ?>, marks its end. Anything found between these tags will be processed as PHP instructions. Outside of these tags, the text is treated as standard text and is output directly.

For example, if you have a file containing both PHP code and regular text, the PHP engine will execute the code enclosed within the <?php ?> tags, while displaying the remaining text as is. A blank line at the end of a PHP script is a good practice to ensure a clean terminal prompt after execution.

Why Use Comments in PHP?

Like most programming languages, PHP supports comments. Comments are sections of text within your code that the PHP engine completely ignores during execution. They serve a variety of crucial purposes.

Primarily, comments allow you to add explanatory notes directly into your code. These notes can describe how a particular section of code functions, explain the reasoning behind a specific design choice, or serve as a reminder for future tasks. This is invaluable for both yourself and anyone else who might read or maintain your code.

Beyond documentation, comments are incredibly useful during development. Sometimes, you might want to temporarily disable a block of code without permanently deleting it – perhaps when debugging or experimenting with a different approach. Simply converting the code into a comment allows you to quickly enable or disable that section as needed. Finally, comments can also be used to store information for automated tools, such as documentation generators or testing frameworks.

Types of PHP Comments

PHP offers a simple and straightforward way to create comments.

Single-Line Comments

The most common type of comment in PHP is the single-line comment. These comments begin with two forward slashes (//). Everything on the same line after those two slashes is treated as a comment and ignored by the PHP interpreter. This allows you to place a comment alongside a PHP statement on the same line, without affecting the statement's execution.

print 2 + 2; // This comment will be ignored and 4 will be printed

In this example, the print statement will still execute, displaying the result of 2 + 2. The text following the // is purely for human readability.