Can you fix this code to avoid using pointers?

[Adam D. Ruppe via Digitalmars-d-learn]

On Saturday, 11 March 2017 at 14:49:42 UTC, XavierAP wrote:
> But also I don't want to modify the function signature, 
> certainly in this way.

It is already copied by the time you get in to the function 
though because of the signature (unless they are constructed 
in-place at the call site).

But you can also do an unrolled loop with AliasSeq 
http://dpldocs.info/experimental-docs/std.meta.AliasSeq.html

import std.meta;
import std.exception;
void calc(double in1, double in2, double in3, double in4)
in {
    foreach(ref item; AliasSeq!(in1, in2, in3, in4))
       enforce(item > 0);
}
body { /* ... */ }

Note that if the loop body is large, this could bloat the code 
slightly since a foreach over AliasSeq is always an unrolled 
loop. But that's probably irrelevant to you.