Re: RFC 299 (v1) C<@STACK> - a modifyable C<caller()>

> Add a new special variable, C<@STACK> to replace the C<caller()>
> function. Allow people to modify the call stack in certain, very
> restricted ways.

>     Perl 6     => Perl 5
>     $STACK[-1]  = [caller(0)];
>     $STACK[-2]  = [caller(1)];

I strongly agree with the opinion that we should try and get away from
special variables and switches in favor of functions and pragmas.
Witness 'use base' instead of '@ISA', 'use warnings', and so on.

Instead of a whole new array, why not just add an additional variable to
caller() that pops off that many stacks permanently?

   $pkg = caller(1);       # back one stack frame
   $pkg = caller(1, 2);    # back one stack, "pop" off
                           # two stack frames also

Or, add a new stack() function that returns an array of the frame(s)
popped off:

   @frame = stack;         # pop off one frame
   stack(2);               # pop off two frames

But making a special variable which can only be popped off and breaks
the nice encapsulation of the caller() function? Bleech, honestly.

-Nate