How to specify this for anonymous functions in PHP

Regarding closure anonymous functions, a very typical problem inJSis to bind it to athisscope. In fact, this problem also exists inPHP, such as the following code:

$func = function($say){ echo $this->name, '：', $say, PHP_EOL; }; $func('good'); // Fatal error: Uncaught Error: Using $this when not in object context

In this anonymous function, we use$this->nameTo get the$nameattribute under the current scope, but who is this$this? We have not defined it, so an error will be reported directly here. The error message is:$thisis used but there is no object context, that is, the scope of the $this reference is not specified.

1.bindTo() method binding $this

$func = $func->bindTo($lily, 'Lily'); // $func = $func->bindTo($lily, Lily::class); // $func = $func->bindTo($lily, $lily); $func1('cool');

This time you can output normally.bindTo()The method is to copy a current closure object and then bind it to the$thisscope and class scope.

• The $lily parameter is aobject $newthisparameter, which is to specify$thisfor this copied anonymous function.

• 'Lily' binds a new class scope, which represents a type and determines which private and protected methods can be called in this anonymous function

If this parameter is not given, then we cannot access the$nameattribute of thisprivate:

$func1 = $func->bindTo($lily); $func1('cool2'); // Fatal error: Uncaught Error: Cannot access private property Lily::$name

2.call() method binding $this

$func->call($lily, 'well'); // Lily：well

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