How to return TRUE|FALSE from class in PHP

Question

Hey there!

I was wondering why my php program is not returning the correct TRUE FALSE value when the class is included elsewhere

it goes something like this

source: signup.php

class signup
{
    function buildProfile()
    {
        if($logic){
            $this->success = TRUE;
        }else{
           $this->success = FALSE;
        }
    }
    function __construct()
    {
        $this->success = NULL;
        $this->buildProfile
        return $this->success;
    }
}

and elsewhere I do

include('signup.php');

$signup = new signup();

if($signup){
    successFunction();
}else....

but it's not getting $signup == true, it's getting FALSE every time

Answer 1

Constructors always return a new instance of the class. You cannot return any other type of value from a constructor. A better way to structure your code would be something like:

source: signup.php

class Signup
{
    public $success;
    protected function buildProfile()
    {
        if($logic){
            $this->success = true;
        }else{
            $this->success = false;
        }
    }
    public function __construct()
    {
        $this->success = null;
        $this->buildProfile();
    }
}

Then when you construct the object you could do:

include('signup.php');

$signup = new Signup();

if($signup->success){
    successFunction();
}else....

Answer 2

With that here :

$signup = new signup();

You are creating an instance of the class, via its constructor.

A constructor is not a normal function : I don't think it can actually "return" anything : it is just here to initialize some data in the object upon its instanciation.

With that, you $signup variable is an object ; an instance of class signup ; it's not any other kind of value, whatever return instruction you'll write in your constructor.

Quoting from wikipedia's Constructor page :

A constructor is similar to an instance method, but it differs from a method in that it never has an explicit return type, it is not inherited, and usually has different rules for scope modifiers.

Answer 3

You cannot return a value from a constructor.

A constructor's sole purpose is to initialize an object. In your example, $signup is your object, it's not a "return value" from the constructor.

Answer 4

You are attempting to imitate a "default functor", a feature that is not present in PHP until 5.3, e.g. you are trying to evaluate an object as if it were a function (as said above, ``new'' always returns you object instances). Objects aren't functions, so a default functor is an instance method that gets automagically executed when its object is invoked as a function.

Either way, the correct solution is in the top answer.

Answer 5

Perhaps a static method would be more appropriate?

http://php.net/manual/en/language.oop5.static.php

include('signup.php');

if(Signup::buildProfile()){
    successFunction();
}else....

Answer 6

By the way, don't write things like this:

if($logic) {
    $this->success = true;
}else{
    $this->success = false;
}

write things like this:

$this->success = $logic;