alias template parameter

[Marc Schütz via Digitalmars-d-learn]

On Friday, 21 June 2013 at 14:08:43 UTC, Sergei Nosov wrote:
> If I have a function
> auto apply(alias fun, T...)(T args)
> {
>     return fun(args);
> }
>
> And then I have
> int y = 2;
> apply!(x => y)(1);
>
> How in the world does this work? Is the context address known 
> at compile-time?

No, but because lambdas are always unique, there will always be a 
dedicated template instance for every time you do this. The 
compiler will then hard-wire that instance to make it able to 
access the context pointer. By the way, you can also pass local 
variables by alias, in which case the same will happen. I guess 
it does so by passing the offset of the variable in the current 
stack frame (unless it's inlined and optimized, of course), but I 
don't know the details. I guess it's up to the compiler.