need `this` for `this` of type `ref @safe Test(string reg_arg)

[Paul Backus]

On Sunday, 18 June 2023 at 19:05:19 UTC, rempas wrote:
> On Sunday, 18 June 2023 at 18:17:16 UTC, Paul Backus wrote:
>>
>> `__ctor` doesn't create a new object, it initializes an 
>> existing object. You need to create the object first, then 
>> call `__ctor` on it:
>>
>> ```d
>> void main() {
>>   Test test;
>>   test.__ctor!("non_def")("Hello");
>> }
>> ```
>
> Thank you! Do you know any other way to do it without using 
> "__ctor".

No, there is no way to pass template arguments to a constructor 
without using `__ctor`.

My recommendation is to use a free function or a `static` method 
instead. For example:

```d
import std.stdio;

struct Test {}

Test makeTest(string type = "def")(string reg_arg)
{
     writeln("reg_arg: ", reg_arg);
     return Test();
}

void main()
{
     auto test = makeTest!"non_def"("Hello");
}
```