D without a GC

[Ulrik Mikaelsson]

2011/1/3 Iain Buclaw <ibuclaw at ubuntu.com>:
> == Quote from bearophile (bearophileHUGS at lycos.com)'s article
>> Dmitry Olshansky:
>> > As stated in this proposal they are quite useless, e.g. they are easily
>> > implemented via mixin with alloca.
>> Thank you for your comments. Here I have added some answers to your comments:
>> http://d.puremagic.com/issues/show_bug.cgi?id=5348
>> Bye,
>> bearophile
>
> Some thoughts to your proposal:
>
>> void bar(int len) {
>>     Foo* ptr = cast(Foo*)alloca(len * Foo.sizeof);
>>     if (ptr == null)
>>         throw new Exception("alloca failed");
>>     Foo[] arr = ptr[0 .. len];
>>     foreach (ref item; arr)
>>         item = Foo.init;
>>
>>     // some code here
>>     writeln(arr);
>>
>>     foreach (ref item; arr)
>>         item.__dtor();
>> }
>
> 1) Why call the dtors manually? Forgive me if I'm wrong, but iirc, alloca will
> free the memory when the stack exits from the current frame level. :)
The dtor doesn't free memory, it allows the class to perform cleanup
on destruction, such as close():ing any native FD:s etc.

Actually, AFAICT, the above code should also after "item=Foo.init"
call item.__ctor(), to allow the constructor to run.

IMHO, stdlibs should provide wrappers for this type of functionality.
An application-writer should not have to know the intricate details of
__ctor and __dtor as opposed to memory-mangement etc. A template
"stackAllocate!(T)" would be nice.