Right I could work around the issue with the return by reference without
any problem.
I am still thinking that if you try to write a meta-circular interpreter
you gonna work very hard
to make this subtleties worked. And according to "Shriram Krishnamurthi"
in his textbook PLAI:
" a truly powerful language is one that makes it easy to write its
meta-circular interpreter."
-- Mathieu Suen
Ionut G. Stan wrote:
I guess what Mathieu is trying to say is that this:
class Foo
{
public $bar = array();
}
$foo = new Foo;
$foo->bar[3] = 1;
var_dump($foo);
...is inconsistent with this:
class Foo
{
public function __get($property)
{
if (! isset($this->$property)) {
$this->$property = array();
}
return $this->$property;
}
}
$foo = new Foo;
$foo->bar[3] = 1;
var_dump($foo);
...or even this:
class Foo
{
private $bar = array();
public function __get($property)
{
return $this->$property;
}
}
$foo = new Foo;
$foo->bar[3] = 1;
var_dump($foo);
Now, I'm not really sure this is that bad, as there may be use cases
where one would like to return different values every time __get is
called. And, as I wrote in a previous email, there are ways to work
around this inconsistency by using return by reference, so everybody
can be happy. I think.
On 3/19/10 4:56 AM, Etienne Kneuss wrote:
On Thu, Mar 18, 2010 at 5:47 PM, mathieu.suen
<mathieu.s...@easyflirt.com> wrote:
Peter Lind wrote:
On the contrary, it's quite obvious what's going on. In both examples
__get() returns an array as PHP would normally do it (i.e. NOT by
reference) which means that if you try to modify that you'll end up
modifying nothing much. However, in your second example, the point at
which you call __get() indirectly comes before the assign to the zork
array - hence, the $this->zork['blah'] = 'blah'; no longer indirectly
calls __get as object::$zork now exists.
In other words, this is down to you confusing passing a variable by
reference and passing it by value: PHP normally passes arrays by
value, so when __get() returns an array, you're working on a copy of
the array you returned. As someone noted earlier, you can easily
change the behaviour of __get to return variables by reference, should
you want to. However, I personally wouldn't want this to be default
behaviour as that would make debugging apps much more annoying -
things should be consistent, even if consistency at times confuse
people.
Regards
Peter
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