Based on a suggestion by Manu Evans:

https://github.com/WalterBright/documents/blob/5d65426a4e5c434d571e76ae800a267a610bf394/placementnew.md

I recommend that this includes allocator support.

```d
struct Allocator {
    void[] allocate(size_t, TypeInfo ti=null);
    void deallocate(void[]);
}
```

We would need a way to tie into deallocate + destroy. Say perhaps ``delete(allocator) thing;`` statement?

This little bit of convenience would be a huge QoL improvement, as it'll calculate the size needed to be allocated for you (including for say arrays). This can be a bit of paid to do properly due to overflow.

> The size of the memory object of class Type can be retrieved with the expression __traits(initSymbol, Type).length.

```d
pragma(msg, __traits(initSymbol, Foo).length);

struct Foo {
	int x;
}
```

```
onlineapp.d(1): Error: cannot determine the address of the initializer symbol during CTFE
onlineapp.d(1):        while evaluating `pragma(msg, Foo.length)`
```

We need a CTFE'able solution to this, for that argument to hold.

On 31/10/2024 7:33 PM, Richard (Rikki) Andrew Cattermole wrote:
> This little bit of convenience would be a huge QoL improvement, as it'll calculate the size needed to be allocated for you (including for say arrays). This can be a bit of paid to do properly due to overflow.

Ugh s/paid/pain/

On Thursday, 31 October 2024 at 06:23:24 UTC, Walter Bright wrote:
> Based on a suggestion by Manu Evans:
>
> https://github.com/WalterBright/documents/blob/5d65426a4e5c434d571e76ae800a267a610bf394/placementnew.md

> If one desires to use classes without the GC, such as in BetterC, it's just awkward to use emplace.

Walter, you made -betterC, you are supposed to know there is no such thing as "TypeInfo", therefore no such thing as "class", it ain't -betterJava++ is it?

On Thursday, 31 October 2024 at 06:23:24 UTC, Walter Bright wrote:
> Based on a suggestion by Manu Evans:
>
> https://github.com/WalterBright/documents/blob/5d65426a4e5c434d571e76ae800a267a610bf394/placementnew.md

Can you add an example?

On Thursday, 31 October 2024 at 06:23:24 UTC, Walter Bright wrote:
> Based on a suggestion by Manu Evans:
>
> https://github.com/WalterBright/documents/blob/5d65426a4e5c434d571e76ae800a267a610bf394/placementnew.md

Sounds great. No notes. 👍

On 10/30/2024 11:33 PM, Richard (Rikki) Andrew Cattermole wrote:
> I recommend that this includes allocator support.

An allocator should be able to deliver a void[], I'm not seeing where specialized support for it is needed.

On 10/30/2024 11:33 PM, Richard (Rikki) Andrew Cattermole wrote:
> We need a CTFE'able solution to this, for that argument to hold.

Currently, there isn't a compile time solution for the allocated size of a class object.

For CTFE, just use plain ordinary new.