Zeev,
Auto-conversion does not validate input to the function/method, it merely
obfuscates the "wrong" input by converting it to desired type resulting in a
potentially un-expected value. I must say I am completely against the
auto-conversion hint idea.
As far as your example goes consider a function that expects a boolean, but
instead gets an int/string/float, which in nearly all cases will result in
TRUE. Which is not the desired outcome.
On Thu, May 27, 2010 at 1:42 AM, Zeev Suraski <z...@zend.com> wrote:
> At 00:28 27/05/2010, Davey Shafik wrote:
>
>> You could just as easily say to do:
>>
>> function foo($bar) {
>> $bar = (int) $bar;
>> }
>>
>> as:
>>
>> function foo($bar) {
>> if (!is_int($bar)) {
>> // error
>> }
>> }
>>
>> Why bother with either if that's the case?
>>
>
> I don't think there's any argument that what we're proposing to add to the
> language can already be done using existing functionality. That's true
> whether we're talking about strict type checking, auto-converting type
> hinting, or pretty much any other idea we might come up with.
>
> There are several reasons we still want to add this feature - reducing the
> burden of validating input, making it clearer to the user what the function
> expects (from the API), and in the future - it might allow for certain
> optimizations.
>
> When we come to evaluate which solution we should pick, we should go for
> the solution that is the most consistent with the rest of the language and
> that gives us the most bang for the buck. Auto-converting type hinting
> falls in that category - it's the most consistent with the rest of the
> language, and it's the most useful behavior in the vast majority of cases -
> it stands a chance to become widely used. For every case where you'd
> explicitly care about the zval.type (such as when you need to differentiate
> between false and zero), you'd have dozens of cases where you won't. Adding
> language level support for those rare cases simply doesn't make sense. The
> marginal gain is minimal. The added complexity and confusion is very high.
>
> I'm strictly against having two solutions. It's the worst outcome we could
> reach IMHO - it means we're unable to decide which is better, so we support
> both (kind of like a hi-tech version of http://bit.ly/9I8dHw). I think
> it's the one solution that's worse than implementing strict typing only - it
> does mean that I would actually support having strict typing only over
> having both. Still, I think having auto-converting type hints is by far the
> best solution.
>
> Can anybody share with us *common* cases where strict typing would be
> necessary, and the proposed auto-converting type hints won't do?
>
> Zeev
>
>
>
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