PHP: assign function to class method - php

Question

How can I assign a function to a method in a class in PHP? I tried the following:
class Something{
public function __construct(){
$functionNames = array('foo', 'bar')
$variable = 'blablabla';
foreach($functionNames as $functionName){
if(method_exists($this, $functionName))
continue;
$this->{$functionName}() = function($params){ //should create the methods "foo" and "bar"
echo $variable; //should echo 'blablabla' (I know that the variable was declared outside this function, but how can I access it anyway?)
}; //the error points to here
}
}
}
But this code gives me this error:
Fatal error: Can't use method return value in write context
Does anyone know how I can assign the anonymous function to the class method, while also still being able to access variables outside that function?

Answer 1

You are doing foreach($functionNames as $functionName){ which means that $functionName is a string, not an array. So, don't use $functionName[0].
method_exists takes 2 parameters. One is the object and the other is the method name. It should be:
method_exists($this, $functionName)
As for creating the function, you don't need () on the left side of the =. It should be:
$this->$functionName = function($params) use($variable){
echo $variable;
};
The use($variable) is needed to tell PHP to use that variable inside the function. That's how closures work in PHP, it's different than other languages.
So, your class should look like:
class Something{
public function __construct(){
$functionNames = array('foo', 'bar');
$variable = 'blablabla';
foreach($functionNames as $functionName){
if(method_exists($this, $functionName)){
continue;
}
$this->$functionName = function($params) use($variable){
echo $variable;
};
}
}
}
Problem here is that in this way of making functions, you are not actually creating a class method, but instead creating a class variable that contains a function.
So, you need to call it like so:
$test = new Something;
$foo = $test->foo;
$foo('abc');
You can't just do $test->foo('abc');.
EDIT: Another thing you can do is use PHP's __call "magic method". This will be ran whenever you do ->funcName(), regardless of whether the method exists or not. Using that method, you can just check to see if the method called was 'foo' or 'bar'. See this example:
class Something{
private $variable;
public function __construct(){
$this->variable = 'blablabla';
}
public function __call($name, $params=array()){
if(method_exists($this, $name)){
// This makes sure methods that *do* exist continue to work
return call_user_func(array($this, $name), $params);
}
else{
$functionNames = array('foo', 'bar');
if(in_array($name, $functionNames)){
// You called ->foo() or ->bar(), so do something
// If you'd like you can call another method in the class
echo $this->variable;
}
}
}
}
With this, now you can do the following:
$test = new Something;
$test->foo('abc'); // Will echo "blablabla"