On Monday, 25 July 2016 at 05:00:23 UTC, Ali Çehreli wrote:
On 07/24/2016 07:15 PM, Gorge Jingale wrote:
Is there a static ternary if?
(A == B) ? C : D;
for compile type that works like static if.
The way to force an expression at compile time is to use it for
something that's needed at compile time. For example, you can
initialize a manifest constant (enum) with that expression:
void main() {
enum i = (__MODULE__.length % 2) ? 42 : 43;
pragma(msg, i);
}
Instead of enum, you can use 'static const' as well.
Ali
It also works for "real" enumerated types.
********************************
enum ver = 0; // version(Windows) ... else ....
enum VersionRelative1
{
A = ver ? 1 : 2,
B = ver ? 3 : 4,
}
enum VersionRelative2
{
A = !ver ? 1 : 2,
B = !ver ? 3 : 4,
}
unittest
{
static assert(VersionRelative1.A == 2);
static assert(VersionRelative2.A == 1);
}
********************************
which is quite cool and not widely known.
