People keep calling the following invalid:
function method(MyClass $param1=null, $param2)
I'm way behind the times (running 4.3.6), but take a
look at how 4.3.6 behaves!:
<?
function method($param1=null,$param2) {
print "$param1:$param2\n";
}
method(1,2);
method(1);
?>
produces
1:2
Warning: Missing argument 2 for method() in /tmp/badopt.php on line 2
1:
Notice: Undefined variable: param2 in /tmp/badopt.php on line 3
***********
*** Perfect! PHP already accepts "=null" before a mandatory
*** parameter and already knows not to use the null as a
*** default value if a mandatory parameter follows! That's
*** exactly what you want for the type hint that allows null
*** case.
***********
- Todd
On Tue, 2004-10-19 at 10:29, Todd Ruth wrote:
> On Tue, 2004-10-19 at 02:42, Christian Schneider wrote:
> > The only restrictions I see is that it makes the parameter optional as
> > well (something I don't consider a problem as it is probably desirable
> > in most cases anyway to be able to leave out an explicit null) and that
> > it only works if no mandatory parameter follows, e.g.
> > function method(MyClass $obj = null, $mandatory);
> > is not possible. Not a real problem either IMHO.
>
> Is it an implementation difficulty that makes that example
> "not possible"? If not, I don't see a problem with it.
> It just means the first parameter is optional in the
> sense that null is allowed. I would be allowed to
> call "method(null, $param)". "method($param)" would
> not be legal. In the implementation, all "optional"
> parameters before the last mandatory parameter would
> be required to be specified by the caller but allowed
> to be null.
>
> I don't believe the argument that a parameter should
> be allowed to be optional but not allowed to be specified
> as null. If I'm allowed to leave out the argument
> entirely, it doesn't do any harm to give me 2 ways to
> say I'm leaving out the argument: one by actually
> not providing an argument and the other by providing
> a null. There is a subtle difference, but it is a
> difference that is already difficult make use of in
> php without func_get_args (not that that's a bad thing).
>
> $.02 (well, less than that)
>
> - Todd
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