add generator layers

src/logic/scripting/lua/lua_util.hpp

@@ -496,17 +496,26 @@ namespace lua {
     }
 
     int pushvalue(lua::State*, const dynamic::Value& value);
+
+    [[nodiscard]]
     dynamic::Value tovalue(lua::State*, int idx);
 
     inline bool getfield(lua::State* L, const std::string& name, int idx = -1) {
         lua_getfield(L, idx, name.c_str());
-        if (isnil(L, -1)) {
+        if (isnil(L, idx)) {
             pop(L);
             return false;
         }
         return true;
     }
 
+    inline int requirefield(lua::State* L, const std::string& name, int idx = -1) {
+        if (getfield(L, name, idx)) {
+            return 1;
+        }
+        throw std::runtime_error("object has no member '"+name+"'");
+    }
+
     inline bool hasfield(lua::State* L, const std::string& name, int idx = -1) {
         lua_getfield(L, idx, name.c_str());
         if (isnil(L, -1)) {