Is it possible to use a class method as a callable parameter to array_map?

Question

I am using php 5.6, I want to do something like this:

class FooBar {
  public function foo() {
    echo "foo!";
    array_map($this->bar, [1,2,3]);
  }

  private function bar() {
    echo "bar!";
  }
}
(new FooBar)->foo();

This gives the following error:

Notice: Undefined property: FooBar::$bar

Alternately, is it possible to declare an anonymous function as a class attribute? Something like this:

class FooBar {
  private $bar = function() {
    echo "bar!";
  }

  public function foo() {
    echo "foo!";
    array_map($this->bar, [1,2,3]);
  }
}
(new FooBar)->foo();

This gives me the following error:

Parse error: syntax error, unexpected 'function' (T_FUNCTION)

I was able to get the result I was after with this:

class FooBar {
  function __construct() {
      $this->bar = function() {
        echo "bar!";
      };
  }

  private $bar;

  public function foo() {
    echo "foo!";
    array_map($this->bar, [1,2,3]);
  }
}
(new FooBar)->foo();

However this is less than ideal; I don't think those function definitions belong in the constructor - ideally I'd like to have them be static class methods.

score 2 · Accepted Answer · answered Mar 09 '18 at 21:48

You should specify context to your function:

class FooBar {
  public function foo() {
    echo "foo!";
    array_map([$this, 'bar'], [1,2,3]);
  }

  private function bar() {
    echo "bar!";
  }
}
(new FooBar)->foo();

For more details check http://php.net/manual/en/language.types.callable.php

Is it possible to use a class method as a callable parameter to array_map?

1 Answers1