To Parenthesize or Not to Parenthesize: When Are Parentheses Necessary for PHP Class Instantiation?

PHP Class Instantiation: Parentheses or Not?

When creating an instance of a class in PHP, it's common to wonder if the parentheses following the class name are mandatory. This question arises particularly when there are no constructor parameters involved.

Let's consider two examples:

$foo = new bar;
$foo = new bar();

These two statements are functionally identical. Both will create an instance of the bar class and assign it to the variable $foo.

The Significance of Parentheses

While the parentheses may seem optional, there are actually some subtleties to consider. In PHP, the parentheses serve two main purposes:

1. Instantiation: The parentheses indicate that the subsequent code is an instance creation statement.
2. Function Invocation: Parentheses are also used for function invocation.

In the case of class instantiation, the absence of parentheses can lead to confusion. Without parentheses, PHP will attempt to parse the code as a function invocation. For example:

$object = new bar;
echo $object->name(); // Error: Function "name" not found

In this example, PHP interprets "new bar" as a function call and attempts to find a function named "name", which doesn't exist. Adding parentheses resolves this issue:

$object = new bar();
echo $object->name(); // Success: Function "name" found

Personal Preference

Ultimately, whether to use parentheses or not when instantiating a class without constructor parameters is a matter of personal preference. However, it's important to be aware of the potential for confusion when omitting parentheses.

If you have no specific coding convention, feel free to use the option that you prefer. Some developers prefer to include parentheses for clarity, while others like to omit them for simplicity.

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