Console Menu Structure - How to get node type

Geosesarma · 2019-07-07T21:14:43

Hi, I´m currently developing a little menu system for a console game. As a starting point I divided the Menu in three areas: the actual data structure, a navigation class which can navigate through the "tree" and holds the state (currently active SubMenu) and a class which draws the whole thing. In its simplest form I want it to behave/look like the following: 1) Every "Node" represents a MenuItem 1.1) Each MenuItem can either be a SubMenuItem or an ActionItem 1.2) Every SubMenu can contain 0 to N childs 2) If I navigate to a SubMenuItem and it has childs I want to display them. If I navigate to an ActionItem it should trigger a function. As a class hirarchy to actually build the menu I thought something like this would work: class MenuItem { public: virtual void action() = 0; virtual string& getItemName() = 0; } class ActionItem : public MenuItem { public: void action() override { //Trigger stuff } string& getItemName() { return itemName; } } class SubMenuItem : public MenuItem { private: vector<MenuItem*> childItems; public: void action() override { //What to do? } string& getItemName() { return itemName; } void add(MenuItem* m) {...} void rm(MenuItem* m) {...} MenuItem* find(const string& name) {...} } To create the menu I could then do this: SubMenuItem root, options; ActionItem exit, start, fullScreenMode, windowMode options.add(&fullScreenMode); options.add(&windowMode); root.add(&start); root.add(&options); root.add(&exit); // Should look like this +--start | +--options--+--fullScreenMode | +--windowMode +--exit But now I created myself a problem: How should I actually get the type of my MenuItem? Lets say I want to find the options SubMenu and add some ActionItems at runtime. In order to do this I can call find on the root object but then I only have a MenuItem pointer which can call action() or getItemName(). To get around this problem I could add some methods to my MenuItem interface, but I think that would be the wrong way (as you can see with the action method -> SubMenuItem has no real use for it). Another solution could be the use of dynamic_cast but wouldn´t it be a sign of a bad design? MenuItem* options = root.find("options"); options. ??? //Fix? class MenuItem { public: virtual void action() = 0; virtual string& getItemName() = 0; virtual bool isSubmenu() = 0; virtual vector<MenuItem*> getChild() = 0; } MenuItem* options = root.find("options"); if(options->isSubmenu()) options->getChild().push_back(new ActionItem()); //Or maybe this? SubMenuItem* options = dynamic_cast<SubMenuItem*>(root.find("options")); if(options) options->add(new ActionItem()) Am I on the right track or is this complete bs? Should I use templates (CRTP) for this kind of problem or is maybe the visitor pattern a good match for this problem? I hope you understand my problem can can give me some hints!

For Beginners

Started by Geosesarma July 02, 2019 09:04 PM

30 comments, last by Geosesarma 5 years, 5 months ago

Green_Baron

221

July 07, 2019 08:54 PM

58 minutes ago, DerTroll said:

[snip] doesn't stop you from programming yourself into a corner. [snap]

Had to laugh heartily ?

Geosesarma

Author

July 07, 2019 09:14 PM

In the end the topic has some good thoughts and lots of code which might be helpfull for other people with similar design decisions. For my part I see the initial question solved. Nevertheless I am grateful for any help I have received so far !

Console Menu Structure - How to get node type

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Console Menu Structure - How to get node type

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