On Thursday, 26 April 2018 at 16:10:16 UTC, Timoses wrote:
Is it possible to use a template to place the "static foreach"
looping to find the correct enum value into? Like I am trying
in the initial "draft" GetMenum?
As the compiler says, the value of `e` is not known at
compile-time. In order to correctly instantiate the template with
that value, all possible instantiations must be instantiated, and
the correct one chosen by a static foreach, just like you do.
The only step you're missing is the template needs to be
instantiated inside the static foreach, like this:
auto instantiateWith(alias Fn, T)(T x)
if (is(T == enum))
{
import std.traits : EnumMembers;
switch (x)
{
static foreach (e; EnumMembers!T)
case e:
return Fn!e;
default:
assert(false);
}
}
enum menum { A, B, C }
template Temp(menum m)
{
enum Temp = m.stringof;
}
unittest {
menum m = menum.A;
import std.stdio;
assert(instantiateWith!Temp(m) == Temp!(menum.A));
m = menum.B;
assert(instantiateWith!Temp(m) == Temp!(menum.B));
m = menum.C;
assert(instantiateWith!Temp(m) == Temp!(menum.C));
}
--
Simen
