Function checkmode

xrepo/packages/l/lua/port/lua/src/ldo.c:952–958

static void checkmode (lua_State *L, const char *mode, const char *x) {
  if (mode && strchr(mode, x[0]) == NULL) {
    luaO_pushfstring(L,
       "attempt to load a %s chunk (mode is '%s')", x, mode);
    luaD_throw(L, LUA_ERRSYNTAX);
  }
}


static void f_parser (lua_State *L, void *ud) {