Why function template 'among' is of complexity O(1) and not O(n)?

[Jakob Ovrum]

On Thursday, 20 February 2014 at 13:40:38 UTC, anonymous wrote:
> When the value is not needed at compile time, the optimizer may 
> go for it, but that's not guaranteed.

That's not really true. The optimizer will never try CTFE because 
of the halting problem. Runtime is runtime, compile-time is 
compile-time - they are clearly separated by the context of the 
expression alone.