"if" statement

[Michelle Long]

On Sunday, 24 March 2019 at 12:45:13 UTC, Francesco Mecca wrote:
> https://run.dlang.io/is/zRcj59
>
> ```
> alias Alg = Algebraic!(int, string);
>
> void main()
> {
> 	int n = 2;
>     Alg value;
>
>     value = n == 2 ? 2 : "string";
> }
> ```
>
> The original code used SumType but the effect is the same.
>
> I suppose that I could write the following:
>
> ```
>     if(n == 2) value = 2;
>     else value = "string";
> ```
>
> Is there a workaround for this that maintains a similar 
> syntactic structure?
> is this behaviour accepted or should the compiler translate the 
> first case in the second?

You could make a Choose function:

auto Ch(A,B)(bool c, A a, B b);

Then

value = Ch(n == 2, n, "string");

Not much different than

value = (n == 2) ? Alg(2) : Alg("string");

except you don't have to write Alg all the time.

The compiler should translate the first but that requires 
implicit conversion of any of the types T... to Algebraic!T... . 
Of course, that should be possible but is it?