Interface Limitations in D

[Steven Schveighoffer]

On 9/19/21 4:00 PM, Elmar wrote:
> * **`interface`s don't permit runtime constants.**
> 
>        Not limiting, only weird. Constants are stronly-pure niladic 
> (no-arguments) functions and D syntactically doesn't differentiate 
> between zero-argument function calls and variable accesses. I could 
> define a static niladic function with constant return value in an 
> `interface`. But the constant-member-syntax
>        ```D
>        static immutable myVar = 0;
>        ```
>        is easier to write.
> 
>        Constants are no state. The purpose of an interface is to 
> describe API which is not supposed to change at runtime or during 
> software evolution while not fixing behaviour and ideally not fixing 
> future additions.


Not sure what you are saying here.

this code is valid:

```d
interface I
{
   static immutable myVar = 0;
}
```

-Steve