On Sat, 2004-05-01 at 22:09, Marcus Boerger wrote:
> Hello internals,
>
> while working with php 5 the last days i find it more and more
> annoying that we allow NULL with type hints.
> From my perspective allowing NULL with typehints would happen
> only very rare.
I don't think this is true. I think there are a number of cases where
passing NULL is used to "unset" or "delete" something. For example, say
a class supports debugging using a listener model:
class Foo {
function setEventListener(Listener $l) { ... }
}
$foo= new Foo();
$foo->setEventListener(new ConsoleListener());
// ...
$foo->setEventListener(NULL);
This makes perfect sense to me and also gets rid of the constraint of
having to define an "unsetEventListener" method.
To wrap it up: Would you agree that being able to pass NULL to any
pointer argument in C is annoying?
[...]
> 2) (Andi) introduce 'not null' after php 5.0. This won't introduce
> a BC break. But it would require two new keywords 'NOT' and 'NULL'.
> The latter is not a problem because it is a define at the moment
> and the patch (a) shows that it easy to change it into a keyword.
> The problem is the new keyword 'not' which would introduce a BC
> break for everyone using the word 'not' already.
I like this idea best: No magic such as "only when it is the first
default argument" (the question "why" will inevitably come up sooner or
later); plus no BC break.
Concerning the new keyword argument, how about using the exclamation
mark (already meaning "not"), as in:
* function foo(Classname !NULL $val) { }
The same as Andi's suggestion, but using ! instead of "not"
* function foo(Classname $val !NULL) { }
Ditto, but using postfix notation. Comes close to default value
syntax which people are already used to.
* function foo(Classname $val != NULL) { }
This would be even more similar to the default value syntax.
- Timm
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