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.
