Function Reference parameters in Quirrel

[Peach1]

So the Squirrel language already has 'outers' which act like references:

local x = 0; function mod() { x = 5; } mod(); print(x) // x is now 5

x is modified with _OP_SETOUTER; function main() local x gets modified when calling mod() here

Squirrel "Outers" are similar to true references, but Squirrel's outers are limited to locals in the _parent function.

With some modification, how could full references be added to the Quirrel language?

function mod(&x) { x = 5; }  local x = 0; mod(x); print(x);

5

Syntax: Maybe parsing & in CreateFunction could call MarkLocalAsOuter() or something similar?

Then for runtime

In SQVM::CLOSURE_OP() outers seem to get setup on creating the closure:

    if((nouters = func->_noutervalues)) {
        for(SQInteger i = 0; i<nouters; i++) {
            SQOuterVar &v = func->_outervalues[i];
            switch(v._type){
            case otLOCAL: // outer local stack target, possible to use for general references??
                FindOuter(closure->_outervalues[i], &STK(_integer(v._src)));
                break;
            case otOUTER:
                closure->_outervalues[i] = _closure(ci->_closure)->_outervalues[_integer(v._src)];
                break;
            }
        }
    }

To add 'references' to the Quirrel language, "references" would have to be setup right before the function gets called, in _OP_PREPCALL or something? using a modified FindOuter function...

I wish I could create a direct pull request.. I was hoping to first get more insight on how reference parameters would best be implemented