Function addreturn

third-party/lua-5.5.0/src/lua.c:588–597

** Try to compile line on the stack as 'return ;'; on return, stack ** has either compiled chunk or original line (if compilation failed). */

** has either compiled chunk or original line (if compilation failed).
*/
static int addreturn (lua_State *L) {
  const char *line = lua_tostring(L, -1);  /* original line */
  const char *retline = lua_pushfstring(L, "return %s;", line);
  int status = luaL_loadbuffer(L, retline, strlen(retline), "=stdin");
  if (status == LUA_OK)
    lua_remove(L, -2);  /* remove modified line */
  else
    lua_pop(L, 2);  /* pop result from 'luaL_loadbuffer' and modified line */
  return status;
}


static void checklocal (const char *line) {