Add VALIDATE_LUA as a function in lpxserver and lpxclient

luprex/cpp/core/lpxclient.cpp

@@ -20,14 +20,21 @@ public:
     LuaConsole console_;
     PrintChanneler print_channeler_;
     eng::vector<Invocation> delayed_invocations_;
+    lua_State *lua_syntax_checker_;
 
 public:
     LpxClient() {
+        lua_syntax_checker_ = LuaCoreStack::newstate(eng::l_alloc);
+
         set_console_prompt(console_.get_prompt());
 
         set_initial_state_standalone();
     }
 
+    ~LpxClient() {
+        lua_close(lua_syntax_checker_);
+    }
+
     void set_initial_state_connect(const eng::string &hostspec) {
         // Create the world model.
         world_.reset(new World(WORLD_TYPE_PREDICTIVE));
@@ -256,6 +263,13 @@ public:
                 set_initial_state_connect(util::ss("nocert:", datapk, ":8085"));
                 break;
             }
+            case AccessKind::VALIDATE_LUA: {
+                LuaVar closure;
+                LuaDefStack LS(lua_syntax_checker_, closure);
+                eng::string errmsg = LS.load(closure, datapk, "stdin");
+                retpk->write_bytes(errmsg);
+                break;
+            }
             default: {
                 util::dprint("Invalid event_access: ", int(kind));
             }