I'm trying to make functions like empty()
and isset()
work with data returned by methods.
What I have so far:
abstract class FooBase{
public function __isset($name){
$getter = 'get'.ucfirst($name);
if(method_exists($this, $getter))
return isset($this->$getter()); // not working :(
// Fatal error: Can't use method return value in write context
}
public function __get($name){
$getter = 'get'.ucfirst($name);
if(method_exists($this, $getter))
return $this->$getter();
}
public function __set($name, $value){
$setter = 'set'.ucfirst($name);
if(method_exists($this, $setter))
return $this->$setter($value);
}
public function __call($name, $arguments){
$caller = 'call'.ucfirst($name);
if(method_exists($this, $caller)) return $this->$caller($arguments);
}
}
the usage:
class Foo extends FooBase{
private $my_stuff;
public function getStuff(){
return $this->my_stuff;
}
public function setStuff($stuff){
$this->my_stuff = $stuff;
}
}
$foo = new Foo();
if(empty($foo->stuff)) echo "empty() works! \n"; else "empty() doesn't work:( \n";
$foo->stuff = 'something';
if(empty($foo->stuff)) echo "empty() doesn't work:( \n"; else "empty() works! \n";
http://codepad.org/QuPNLYXP
How can I make it so empty/isset return true/false if:
my_stuff
above is not set, or has a empty or zero value in case of empty()
?
Magic methods in PHP are special methods that are aimed to perform certain tasks. These methods are named with double underscore (__) as prefix. All these function names are reserved and can't be used for any purpose other than associated magical functionality. Magical method in a class must be declared public.
"Method" is basically just the name for a function within a class (or class function). Therefore __METHOD__ consists of the class name and the function name called ( dog::name ), while __FUNCTION__ only gives you the name of the function without any reference to the class it might be in.
In PHP function overloading is done with the help of magic function __call(). This function takes function name and arguments.
public function __isset($name){
$getter = 'get'.ucfirst($name);
return method_exists($this, $getter) && !is_null($this->$getter());
}
This check whether or not $getter()
exists (if it does not exist, it's assumed that the property also does not exist) and returns a non-null value. So NULL
will cause it to return false, as you would expect after reading the php manual for isset()
.
A bit more option not to depend on getter
public function __isset($name)
{
$getter = 'get' . ucfirst($name);
if (method_exists($this, $getter)) {
return !is_null($this->$getter());
} else {
return isset($this->$name);
}
}
Your code returns error because of these lines:
if(method_exists($this, $getter))
return isset($this->$getter());
You can just replace it with:
if (!method_exists($this), $getter) {
return false; // method does not exist, assume no property
}
$getter_result = $this->$getter();
return isset($getter_result);
and it will return false if the getter is not defined or it returns NULL
. I propose you should better think of the way you determine some property is set or not.
The above code is also assuming that you are creating getters for all of your properties, thus when there is no getter, the property is assumed as not set.
Also, why are you using getters? They seem to be some overkill here.
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