On 2012-03-02, Anthony Ferrara <ircmax...@gmail.com> wrote:
> Well, there are a few questions about the implementation:
>
> 1. *Which* type casting rules should it follow?
>
> a. Regular cast rules (like $foo = (int) $foo), where it converts
> always without error?
> b. Internal function cast rules, where it warnings on error and
> prevents execution of the function.
> c. Current type hinting rules, where if it can't convert cleanly it
> E_RECOVERABLE_ERRORS
>
> Personally, I like C the best. Where if it is passed an invalid
> value, it attempts to cleanly convert, but errors out if it can't...
> But I can see other arguments being made...
(c) seems the most sane option ot me as well.
> 2. Should (array) be supported? Perhaps. So at that point, foo(array
> $bar) would do a "strict" check, and foo((array) $bar) would attempt
> to cast. But my question would be: what would attempt to cast mean?
> Should it error out if you pass foo(1)? That's what the internal
> function cast rules do. And to me that's more obvious than silently
> converting it to foo(array(1))...
Turn this around and look at it from the current state of PHP:
function foo($bar)
{
$bar = (array) $bar;
}
If you pass a value of 1 for $bar, $bar is then converted to array(1).
That's what I'd expect the following to do as well:
function foo((array) $bar)
{
}
It's casting, and clearly different than:
function foo(array $bar)
{
}
which is doing a typehint check.
> 3. Should references be supported? My feeling is yes, they should.
> So if you do foo((array) &$bar), it would cast the original value (if
> possible) as well.
I personally would expect casting and references to be mutually
exclusive -- if you're casting, you're changing the value type, and I
wouldn't expect a destructive operation like this from passing a value
to a function/method call.
<snip>
> 5. What about BC breaks? Well, this entire patch (up to this point)
> wouldn't require one. it's only adding the casting functionality
> (which is not implemented today), so no problem. Existing code would
> still function fine.
This is something that should be highlighted. I've seen a lot of folks
claiming type hinting is viral, and the arguments make no sense to me.
What your patch is offering is _opt_in_ type casting of function/method
arguments. You don't _have_ to write your functions or methods using
them, and for those who do, it should have no side effects on code
calling it.
I would _LOVE_ to see this as part of PHP.
--
Matthew Weier O'Phinney
Project Lead | matt...@zend.com
Zend Framework | http://framework.zend.com/
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