Function luaO_pushvfstring

lua/lobject.c:122–180

this function handles only `%d', `%c', %f, %p, and `%s' formats */

/* this function handles only `%d', `%c', %f, %p, and `%s' formats */
const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
  int n = 1;
  pushstr(L, "");
  for (;;) {
    const char *e = strchr(fmt, '%');
    if (e == NULL) break;
    setsvalue2s(L, L->top, luaS_newlstr(L, fmt, e-fmt));
    incr_top(L);
    switch (*(e+1)) {
      case 's': {
        const char *s = va_arg(argp, char *);
        if (s == NULL) s = "(null)";
        pushstr(L, s);
        break;
      }
      case 'c': {
        char buff[2];
        buff[0] = cast(char, va_arg(argp, int));
        buff[1] = '\0';
        pushstr(L, buff);
        break;
      }
      case 'd': {
        setnvalue(L->top, cast_num(va_arg(argp, int)));
        incr_top(L);
        break;
      }
      case 'f': {
        setnvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));
        incr_top(L);
        break;
      }
      case 'p': {
        char buff[4*sizeof(void *) + 8]; /* should be enough space for a `%p' */
        sprintf(buff, "%p", va_arg(argp, void *));
        pushstr(L, buff);
        break;
      }
      case '%': {
        pushstr(L, "%");
        break;
      }
      default: {
        char buff[3];
        buff[0] = '%';
        buff[1] = *(e+1);
        buff[2] = '\0';
        pushstr(L, buff);
        break;
      }
    }
    n += 2;
    fmt = e+2;
  }
  pushstr(L, fmt);
  luaV_concat(L, n+1, cast_int(L->top - L->base) - 1);
  L->top -= n;
  return svalue(L->top - 1);