Squirrel

Hello! Is it posible to attach my data to Squirrel table?
Here is the C++ code for piece creation.

class Piece
{
public:
    HSQOBJECT mScriptObject;
};

int createPiece(HSQUIRRELVM v)
{
    Piece* piece = new Piece();

    sq_newtable(v); //create table
//set the table's data to piece
    sq_pushstring(v, "ID", -1);
    sq_pushinteger(v, 2);
    sq_newslot(v, -3, SQFalse);

    sq_resetobject(&piece->mScriptObject); //initialize the handle
    sq_getstackobj(v,-1,&piece->mScriptObject); //retrieve an object handle from the pos –2
    sq_addref(v,&piece->mScriptObject); //adds a reference to the object

    return 1;
}

And to delete piece, I use this:

int bgwDestroyPiece(HSQUIRRELVM v)
{
    Piece* piece;
//get user data of table

    sq_release(v,&piece->mScriptObject); //relese the object
    delete piece;

    return 0;
}

Here is how it looks in Squirrel scripts:

local piece = createPiece();
piece.posX <- 10;
destroyPiece(piece);

I don't want user to be able to change the user data of the table and I need it to be table, so that script can add slots to table like this: piece.posX <- 10. Is it possible with Squirrel?
Thanks in advance!

If it is not possible to attach user data to table, I can create a slot like this:

sq_pushstring(v, "userData", -1);
sq_pushuserpointer(v, piece);
sq_newslot(v, -3, SQFalse);

But if user calls this in script, it crashes the program:
piece.userData = 0;

Is it possible to protect table's slots somehow, so that they are not accessible from script?

Ok, I see, that squirrel supports constants (like this: const variable = value). Is it possible to create constant from C++? I think I could save the user data in constant, so that script wouldn't be able to change it.

It is possible to set foreign pointer for Virtual Machine with sq_setforeignptr. Is there something similar for HSQOBJECT?
Can somebody please answer me?

Is it possible for me tu suggest a patch?
I would like to add void *_foreignptr; to HSQOBJECT (like in SQVM).
And add these functions to sqapi.h:

void sq_setforeignptr(HSQOBJECT o,SQUserPointer p)
{
    o->_foreignptr = p;
}

SQUserPointer sq_getforeignptr(HSQOBJECT o)
{
    return o->_foreignptr;
}

have you considered using a class instead?
class instances can have userdata attached.

Alberto