Adding a class with Generic Lists inside a Generic List

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So I have this class for character dialogs and I'm building a set of Lists using it

 class ScriptStep {
     var stepType : StepType;
     var subScript : List.<ScriptStep>;
     var stepDuration : float;    
     var stepTransform : Transform;
     var audioClip : AudioClip;
     var textLine : String;
     var stepAction : function():void;
     var stepActionFade : function(float):void;
     var stepSelectedObject : Obj_Properties_Class;
     var stepPlayerTask : PlayerTaskList;
     var stepWifeTask : WifeTaskList;
     var stepBurglar01Task : Burglar01TaskList;
     var cooperateScript : List.<ScriptStep>;
     var refuseScript : List.<ScriptStep>;
 }

Everything is working well until I realized that by adding those 2 extra variables in the class:

         var cooperateScript : List.<ScriptStep>;
         var refuseScript : List.<ScriptStep>;

My .unity file size changes from 600k to 100Mb and the game takes ages to run when I press "Play". Everything runs fine but its like I added a huge slowdown.

If I remove those 2 variables in the class everything goes back to normal. I would like to understand why this is happening. Am I typing the variables badly? Am I not allow to add a list inside another list?

Any help very appreciated!

Answer 1

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Answer by Negagames · Jul 13, 2013 at 04:20 AM

You have a list inside of a list. Think of two mirrors pointing at each other. Each of the images within another image is a representation of your list-ception. I think the only reason it goes to 100MB is because the is the buffer limit. If you didn't have an overflow limit. Putting a list inside a list would cause your computer to crash.

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iwaldrop · Jul 13, 2013 at 04:27 AM 0

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It's not just that there's a list inside of a list; it's that its a list of the same type of object that contains it. There are three lists of ScriptStep inside of the ScriptStep class. Although the OP doesn't post any initialization logic, what's happening is very likely that for each ScriptStep object that is created a bunch of other ScriptSteps are being created which promptly cascades out of control.

Spend some time thinking about the architecture of your dialogues; it's quite possible that you'll discover a way to do what you want without recursive data structures.

castor · Jul 13, 2013 at 07:08 AM 0

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Aaa I see! It makes perfect sense. Now I realized I can get away with my current layout with having just one List.; inside the class rather than three but what you guys mention makes me think that even one is a bad decision? Is it something I should always avoid? Having a list inside a list of the same class?

iwaldrop · Jul 13, 2013 at 04:54 PM 0

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Yes, probably, for the same reason.

If class T has a list of type T, and initialized is, then, when you instantiate the first instance of T, you begin cascading process of instantiating n Ts.

T1 has T[] has many T[]s has many more T[]s, who all have the same root (T1). You'll never get to create T2 because T1 has been creating millions (hyperbole) of instances of T within itself.

castor · Jul 13, 2013 at 04:58 PM 0

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Thanks! So how would I go about solving a problem like this? Creating a new class type?

iwaldrop · Jul 13, 2013 at 05:02 PM 0

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Well, I'd recommend starting a new question for this. Be sure to note whether you initialize your lists, and what the function of ScriptStep is. In general, however, you should probably store you ScriptSteps in another class that can serve individual ScriptSteps according to your need.

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Adding a class with Generic Lists inside a Generic List

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