Ambiguity issue with expanding and evaluating single template type parameter enums

[data pulverizer]

On Tuesday, 28 December 2021 at 00:32:03 UTC, Paul Backus wrote:
> The result of `.stringof` is completely implementation-defined, 
> may change arbitrarily between compiler releases, and is not 
> even guaranteed to be valid D code in the first place.

Wow, I didn't know this.

> In this case, the simplest solution is to have your code 
> generator accept a string as its input, rather than a type. For 
> example:
>
> ```d
> enum instantiate(string type, string expr) = type ~ "(" ~ expr 
> ~ ")";
> pragma(msg, instantiate!("RVector!(SEXPTYPE.REALSXP)", "x"));
> ```

Well the code needs to be responsive from parameter types `T` 
generated from other code. I'm allowing the user to create 
functions select those they wish to access in R by UDA decorators 
in the D script which I then filter for and wrap the necessary 
functions generating any type conversion code I need at compile 
time to create functions callable in R.