Function codenot

3rd/lua-5.4.3/src/lcode.c:1168–1196

** Code 'not e', doing constant folding. */

** Code 'not e', doing constant folding.
*/
static void codenot (FuncState *fs, expdesc *e) {
  switch (e->k) {
    case VNIL: case VFALSE: {
      e->k = VTRUE;  /* true == not nil == not false */
      break;
    }
    case VK: case VKFLT: case VKINT: case VKSTR: case VTRUE: {
      e->k = VFALSE;  /* false == not "x" == not 0.5 == not 1 == not true */
      break;
    }
    case VJMP: {
      negatecondition(fs, e);
      break;
    }
    case VRELOC:
    case VNONRELOC: {
      discharge2anyreg(fs, e);
      freeexp(fs, e);
      e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0);
      e->k = VRELOC;
      break;
    }
    default: lua_assert(0);  /* cannot happen */
  }
  /* interchange true and false lists */
  { int temp = e->f; e->f = e->t; e->t = temp; }
  removevalues(fs, e->f);  /* values are useless when negated */
  removevalues(fs, e->t);
}


/*