Function raw_arith 

pub fn raw_arith(
    state: &mut LuaState,
    op: ArithOp,
    p1: &LuaValue,
    p2: &LuaValue,
    res: &mut LuaValue,
) -> Result<bool, LuaError>

Attempts raw (no-metamethod) arithmetic on two Lua values. Writes the result to res and returns true on success, false if the operation cannot be performed with the given types (caller should invoke a metamethod instead).

C: int luaO_rawarith (lua_State *L, int op, const TValue *p1, const TValue *p2, TValue *res)