Help with PHP if statement

[thomasj]

Hi guys,
I have a little trouble understanding exactly how the following if-statement works:

$this->s = ($this->k < 4) ? ($this->k < 3) ? ($this->k < 2) ? ($this->k < 1) ? Null : imagecreatefromgif($this->a) : imagecreatefromjpeg($this->a) : imagecreatefrompng($this->a) : Null;

(s being an image and k type of the image, k = 1 is gif, k=2 is jpg, k=3 is png)

Background: I would need to remove the gif support (this is from GD library, the hosted version doesn't support gif)

regards Thomas

[laserlight]

You're probably looking at gross abuse of the ternary operator.

Here's what I think the more normal form should be:

if ($this->k < 4) {
	if ($this->k < 3) {
		if ($this->k < 2) {
			if ($this->k < 1) {
				$this->s = Null;
			} else {
				$this->s = imagecreatefromgif($this->a);
			}
		} else {
			$this->s = imagecreatefromjpeg($this->a);
		}
	} else {
		$this->s = imagecreatefrompng($this->a);
	}
} else {
	$this->s = Null;
}

Here is a simple version that uses the information given "k type of the image, k = 1 is gif, k=2 is jpg, k=3 is png"

switch ($this->k) {
case 1:
	$this->s = imagecreatefromgif($this->a);
	break;
case 2:
	$this->s = imagecreatefromjpeg($this->a);
	break;
case 3:
	$this->s = imagecreatefrompng($this->a);
	break;
default:
	$this->s = Null;
}