On 1/2/2013 4:18 PM, Steve Clay wrote:
On 1/2/13 4:18 PM, Clint Priest wrote:
Omitting isset/unset has the same effect as declaring it without a
body. This is
described in the RFC under Automatic Implementations with this line:
Note that isset/unset implementations will always be provided if they
are not defined or
if they are explicitly auto-defined (as above).
I think the RFC could make this clearer: "isset & unset are always
provided with the default implementations unless the author provides
his/her own."
I can do that, no problem.
Looking closer at the default implementations of isset/unset, I'm
worried these could lead to confusion. Consider this code:
class TimePeriod {
private $Seconds = 3600;
public $Hours {
get { return $this->Seconds / 3600; }
set { $this->Seconds = $value; }
}
}
The RFC's default implementation is always bound to the shadow
property, so here's what you really get:
class TimePeriod {
private $Seconds = 3600;
public $Hours {
get { return $this->Seconds / 3600; }
set { $this->Seconds = $value; }
// auto-generated
isset { return $this->Hours != NULL; }
unset { $this->Hours = NULL; }
}
}
Note the resulting behavior:
$t = new TimePeriod;
$t->Hours; // 1
isset($t->Hours); // false !?
unset($t->Hours);
$t->Hours; // still 1
Effectively, authors who don't base their getters/setters on the
shadowed property must be urged to create their own isset/unset
because the default ones would be useless. I'm not crazy about this.
Sorry, there was a typo in that RFC there, this line:
isset { return $this->Hours != NULL; }
Should have been with !==:
isset { return $this->Hours !== NULL; }
I've already updated the 1.2 doc to reflect the correct way.
Given what I mentioned above, I'm assuming you did not test this with
the fork, right? Just based your comments on how it should logically
work (with the incorrect != vs !==?)
One last thing about that, the isset/unset with $this->Hours calls the
getter to retrieve the $this->Hours value, so it behaves as your example
below indicates.
I'd prefer these default implementations:
isset { return $this->__getHours() != NULL; }
unset { $this->__setHours(NULL); }
$t = new TimePeriod;
$t->Hours; // 1
isset($t->Hours); // true
unset($t->Hours);
$t->Hours; // null
isset($t->Hours); // false
Note these also work as expected when using the default get/set
implementations. Of, course, my implementations don't actually *work*
because you can't call an accessor from an accessor...
Steve, are you testing these w/ the fork? Sounds like you are... But
your above sentence is not accurate, you can call an accessor from an
accessor. isset { return $this->Hours !== NULL; } calls the getter for
the value and compares it with NULL.
Steve Clay
--
-Clint
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