PHP constructor invocation syntax

Question

Usually I create a new object invocating his constructor the usual way:

$instance= new Class();

Lately, I'm reading a lot of code with an alternative syntax (without the parentesys):

$instance= new Class;

There are substantial differences between the two methods or are they equivalent?

I haven't found references on this topic 'till now.

As far as I know, unless you need to pass parameters to your constructor, both expressions are identical. Correct me if I am wrong. — Jay Zeng
– Jay Zeng, Commented Jan 28, 2010 at 0:45
As far I know, I agree with you. I would like to be sure this is an intended feature, though. — Eineki
– Eineki, Commented Jan 28, 2010 at 1:27

cletus · Accepted Answer · 2010-01-28 01:45:51Z

5

There is no difference.

You're right about this being hard to prove. The Basics introduces the new keyword but all examples have parentheses and no mention is made of their optionality.

Edit: best I can find are examples from the official documentation such as:

// This will call B() as a constructor
$b = new B;

edited Jan 28, 2010 at 1:45

answered Jan 28, 2010 at 0:41

cletus

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1 Comment

Eineki Over a year ago

Just what I was searching. Thanks

pagboy · Accepted Answer · 2010-01-28 00:42:12Z

0

I am not familiar with PHP, but the latter probably invokes the default constructor, while the former invokes the constructor with no parameters.

answered Jan 28, 2010 at 0:42

pagboy

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2 Comments

Decent Dabbler Over a year ago

Unfortunately, PHP doesn't support multiple constructors. Nice try though. :)

sfrench Over a year ago

Re: No multiple constructors. True, however you can omit them and if default values are provided in the signature they will be substituted in when the call is made.

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