Improve print() function

Basically the original, but with Serial

src/LuaWrapper.cpp

@@ -18,10 +18,26 @@ extern "C" {
     delay(a);
   }
 
-  static int lua_wrapper_print(lua_State *lua) {
-    String a = String(luaL_checkstring(lua, 1));
-    Serial.println(a);
-  }
+  static int lua_wrapper_print (lua_State *L) {
+    int n = lua_gettop(L);  /* number of arguments */
+    int i;
+    lua_getglobal(L, "tostring");
+    for (i=1; i<=n; i++) {
+      const char *s;
+      size_t l;
+      lua_pushvalue(L, -1);  /* function to be called */
+      lua_pushvalue(L, i);   /* value to print */
+      lua_call(L, 1, 1);
+      s = lua_tolstring(L, -1, &l);  /* get result */
+      if (s == NULL)
+        return luaL_error(L, "'tostring' must return a string to 'print'");
+      if (i>1) Serial.write("\t");
+      Serial.write(s);
+      lua_pop(L, 1);  /* pop result */
+    }
+    Serial.println();
+    return 0;
+}
 
   static int lua_wrapper_millis(lua_State *lua) {
     lua_pushnumber(lua, (lua_Number) millis());