PHP closures of $this

phpCantCloseThis.php

// Apparently this is fixed in php 5.4

$ php -a
Interactive shell

php > /**
/*  >  * Demonstrate that you can use $this to refer to a member variable / property.
/*  >  */
php > class NullHypothesis {
php {   function foo() {
php {     $this->x = 123;
php {     return $this->x;
php {   }
php { }
php > echo 'Null: ';
Null: 
php > $a = new NullHypothesis();
php > echo "x{$a->foo()}x\n";
x123x
php > /**
/*  >  * Demonstrate that you can use $this in an anonymous function inside a method.
/*  >  */
php > class ThisImplicitClosure {
php {   function foo() {
php {     $this->x = 123;
php {     $f = function () { return $this->x; };
php {     return $f();
php {   }
php { }
php > echo 'Implicit: ';
Implicit: 
php > $b = new ThisImplicitClosure();
php > echo "x{$b->foo()}x\n";

Fatal error: Using $this when not in object context in php shell code on line 4
$ php -a
Interactive shell

php > /**
/*  >  * Demonstrate that you can use $this in an explicit closure inside a method.
/*  >  */
php > class ThisExplicitClosure {
php {   function foo() {
php {     $this->x = 123;
php {     $f = function () use ($this) { return $this->x; };
php {     return $f();
php {   }
php { }

Fatal error: Cannot use $this as lexical variable in php shell code on line 4
$ php -a
Interactive shell

php > /**
/*  >  * Demonstrate that you can work around PHP being obtuse.
/*  >  */
php > class ThisSucks {
php {   function foo() {
php {     $this->x = 123;
php {     $self = $this;
php {     $f = function () use ($self) { return $self->x; };
php {     return $f();
php {   }
php { }
php > echo 'Suck: ';
Suck: 
php > $d = new ThisSucks();
php > echo "x{$d->foo()}x\n";
x123x