Initialize to None

[starcanopy]

On Sunday, 6 September 2020 at 03:42:36 UTC, N.S. wrote:
> I'd like to check whether a variable is initialized or not. And 
> I'd also like to uninitialize a variable that is already 
> initialized. Thanks!
>
> int x = void;
>
> if (x == void)
> {
>     writeln("x not initialized");
> }
> else
> {
>     // OK, use x
> }
>
> // Uninitialize x
> x = void;

You might consider Nullable from std.typecons; however, if you're 
avoiding implicit initialization for performance reasons, then 
this solution might not be applicable.

import std.stdio: writeln;
import std.typecons: Nullable;

Nullable!int x;

if (x.isNull)
{
	writeln("x not 'initialized'");
}
else
{
	// OK, use x
}

// 'Uninitialize' x
x.nullify();