Function luaK_exp2RK

depends/lua/src/lcode.c:758–776

** Ensures final expression result is in a valid R/K index ** (that is, it is either in a register or in 'k' with an index ** in the range of R/K indices). ** Returns R/K index. */

** Returns R/K index.
*/
int luaK_exp2RK (FuncState *fs, expdesc *e) {
  luaK_exp2val(fs, e);
  switch (e->k) {  /* move constants to 'k' */
    case VTRUE: e->u.info = boolK(fs, 1); goto vk;
    case VFALSE: e->u.info = boolK(fs, 0); goto vk;
    case VNIL: e->u.info = nilK(fs); goto vk;
    case VKINT: e->u.info = luaK_intK(fs, e->u.ival); goto vk;
    case VKFLT: e->u.info = luaK_numberK(fs, e->u.nval); goto vk;
    case VK:
     vk:
      e->k = VK;
      if (e->u.info <= MAXINDEXRK)  /* constant fits in 'argC'? */
        return RKASK(e->u.info);
      else break;
    default: break;
  }
  /* not a constant in the right range: put it in a register */
  return luaK_exp2anyreg(fs, e);
}


/*