Implement probe_lua and add it to lpxclient/lpxserver

luprex/core/cpp/world-core.cpp

@@ -257,6 +257,65 @@ int64_t World::create_login_actor() {
     return tan->id();
 }
 
+std::string World::probe_lua(int64_t actor_id, const std::string &lua) {
+    assert(stack_is_clear());
+    lua_State *L = state();
+
+    Tangible *actor = tangible_get(actor_id);
+    if (actor == nullptr) {
+        return "";
+    }
+
+    LuaVar closure;
+    LuaStack LS(L, closure);
+
+    // create the compiled closure.
+    int status = luaL_loadbuffer(L, lua.c_str(), lua.size(), "=probe");
+    lua_replace(L, closure.index());
+    if (status != LUA_OK) {
+        // The closure is actually an error message. Do nothing.
+        // This should normally not happen: LuaConsole should filter
+        // out syntax errors.
+        LS.result();
+        return "";
+    }
+
+    // Call the closure.
+    int top = lua_gettop(L);
+    lua_pushvalue(L, closure.index());
+    open_lthread_state(actor_id, actor_id, false, true);
+    status = traceback_pcall(L, 0, LUA_MULTRET);
+    
+    // If there's an error message, print it.
+    // Otherwise, pretty-print the results.
+    std::ostream *ostream = lthread_print_stream();
+    if (status == LUA_OK) {
+        for (int i = top + 1; i <= lua_gettop(L); i++) {
+            LuaSpecial root(i);
+            pprint(LS, root, true, ostream);
+            (*ostream) << std::endl;
+        }
+    } else {
+        const char *msg = lua_tostring(L, -1);
+        if (msg == NULL) {
+            msg = "(error object is not a string)";
+        }
+        (*ostream) << msg << std::endl;
+    }
+
+    // Collect the lthread_prints (and also make sure they
+    // don't go into the printbuffer).
+    std::string result = lthread_prints_->str();
+    lthread_prints_.reset();
+
+    close_lthread_state();
+
+    // And we're done.
+    LS.result();
+    assert(stack_is_clear());
+    return result;
+}
+
 void World::update_gui(int64_t actor_id, int64_t place_id, Gui *gui) {
     assert(stack_is_clear());
     gui->clear(place_id);
@@ -391,6 +450,8 @@ void World::invoke_lua(int64_t actor_id, int64_t place_id, const std::string &ac
     lua_replace(L, closure.index());
     if (status != LUA_OK) {
         // The closure is actually an error message. Do nothing.
+        // This should normally not happen: LuaConsole should filter
+        // out syntax errors.
         LS.result();
         return;
     }