so, here's the situation:

current old code has:

typedef const(void*) T0, T1;

which is of course deprecated.

context that needs to work:

struct A
{
    T0 t;
    this(T0 init)
    {
        t = init;
    }
}

Also, I need type-safety. is(T0 == T1) *must* be false.

I have a modified Typedef I'm using to get things started, allowing Typedef!(const(void*), const(void*).init, "T0") to work at all:

struct Typedef(T, T init = T.init, string cookie=null)
{
    static if(init != T.init)
    {
        private T Typedef_payload = init;
    }
    else
    {
        private T Typedef_payload;
    }

    this(T initial)
    {
	Typedef_payload = initial;
    }

    this(typeof(this) initial)
    {
	Typedef_payload = initial.Typedef_payload;
    }

    mixin Proxy!(Typedef_payload);
}

but that doesn't get me all of the way, there's still no way I can see to get the t = init to work. I wish there was some way to call a constructor on a object after it is declared (perhaps with the same rules as const initialisation?).

On Friday, 23 August 2013 at 12:17:08 UTC, John Colvin wrote:
> so, here's the situation:

On 2.063.2 why not something like this:

---
import std.typecons;
alias T0 = Typedef!(void*, null, "T0");
alias T1 = Typedef!(void*, null, "T1");
static assert( ! is(T0 == T1));
struct A
{
    T0 t;
    this(T0 init)
    {
        t = init;
    }
}
void foo(){
    auto a = A(T0(null));
    // auto b = A(T1(null)); Error!
}
---

Paolo

On Friday, 23 August 2013 at 18:58:49 UTC, Paolo Invernizzi wrote:
> On Friday, 23 August 2013 at 12:17:08 UTC, John Colvin wrote:
>> so, here's the situation:
>
> On 2.063.2 why not something like this:
>
> ---
> import std.typecons;
> alias T0 = Typedef!(void*, null, "T0");
> alias T1 = Typedef!(void*, null, "T1");
> static assert( ! is(T0 == T1));
> struct A
> {
>     T0 t;
>     this(T0 init)
>     {
>         t = init;
>     }
> }
> void foo(){
>     auto a = A(T0(null));
>     // auto b = A(T1(null)); Error!
> }
> ---
>
> Paolo

It's const(void*) not just void*

Unfortunately that breaks it.

On Saturday, 24 August 2013 at 09:19:14 UTC, John Colvin wrote:
> On Friday, 23 August 2013 at 18:58:49 UTC, Paolo Invernizzi wrote:
>> On Friday, 23 August 2013 at 12:17:08 UTC, John Colvin wrote:
>>> so, here's the situation:
>>
>> On 2.063.2 why not something like this:
>
> It's const(void*) not just void*
> Unfortunately that breaks it.

Sorry John, you are right, naturally.

- Paolo