Need Advice: Union or Variant?

[jwatson-CO-edu]

On Thursday, 17 November 2022 at 22:49:37 UTC, H. S. Teoh wrote:
> Just create a nested anonymous struct, like this:
>
>  	struct Atom {
>  		F_Type kind;
>  		union {		// anonymous union
> 			struct {
> 				Atom*   car; // ----------------- Left  `Atom` Pointer
> 				Atom*   cdr; // ----------------- Right `Atom` Pointer
> 			}
> 			struct {
> 				double  num; // ----------------- Number value
> 				string  str; // ----------------- String value, D-string 
> underlies
> 			}
>  			bool    bul; // ----------------- Boolean value
>  		}
>  		F_Error err = F_Error.NOVALUE; // Error code
>  	}
>
>
> T
Thank you, something similar to what you suggested reduced the 
atom size from 72 bytes to 40.