[dmd-beta] D 1.075 and 2.060 betas 2

[kenji hara]

2012/7/31 Andrei Alexandrescu <andrei at erdani.com>:
> On 7/30/12 12:25 PM, kenji hara wrote:
>>
>> Unfortunately no. 'static nested struct' never have any frame pointers, so
>>
>> auto map(alias pred, Range)(Range r) {
>>    static struct Result {
>>      .. auto front() { return pred(...); }
>>    }
>> }
>>
>> if pred is a nested function and requires its frame pointer to call
>> it, Result cannot access it.
>
>
> Got it. So is it correct to say that global structs templated with alias
> sometimes save their frame pointers, sometimes not? If so, could you please
> give a few more details on how that choice is made?

Yes, that's right.
I've post a more detail to explain it.
http://d.puremagic.com/issues/show_bug.cgi?id=8463#c7

>>> Longer term, it has become obvious to me that we need a clear and simple
>>> mechanism for a function to save another function passed by alias, even
>>> if
>>> that function holds state. That must happen regardless of interaction
>>> with
>>> Voldemort types. We must have a mean do e.g. define a scope delegate that
>>> holds the alias function and is able to call it. This has been a
>>> long-standing problem that we've avoided in limited cases by relying on
>>> the
>>> built-in frame pointer.
>>
>>
>> The fundamental problem is the same as this.
>>
>> Issue 5710 - cannot use delegates as parameters to non-global template
>> http://d.puremagic.com/issues/show_bug.cgi?id=5710
>
>
> It would be quite a bummer if we can't address this limitation somehow.

I agree, but it seems to me that is fairly difficult...

Kenji Hara