Re: New to D and mimicking C++ : how to implement std::integral_constant<>?

[Jerry via Digitalmars-d-learn]

On Monday, 7 November 2016 at 18:42:37 UTC, Picaud Vincent wrote:
template isIntegralConstant(ANY)
{
    enum bool 
isIntegralConstant=__traits(identifier,ANY)=="IntegralConstant";
}

A bit more elegant way of doing that would be:

enum isIntegralConstant(T) = is(T : IntegralConstant!U, U...);


I would be very graceful for any help/advice that explains the 
right way to implement C++ std::integral_constant<T,T value> in 
the D language.

Vincent

Now the question is, do you really need IntegralConstant? I've 
never used it in C++ so I don't really know any of the use cases 
for it. But generally in D if you need something to be a compile 
time constant value you can just use "enum". It can be any type 
as well, so long as it can be evaluated at compile time.

enum long someConstant = 1 << 32;