How to properly hook into World Variables?

That's the only way. It's not restrictive if done properly. Your single Listener can notify other components that register with it if it wants to. For example, a number of public scripts you can add to your Inspector that you can notify. Think of the Listener as a Manager for changes on that World Variable.

Let me know if I should add some notes to the documentation to make that clearer.

Thanks!

Sure, see the code below. I added the following. Up top:

public YourScriptListener[] YourScriptListeners;


Drag your other Listeners into that field in the Inspector to "register" them. YourScriptListener isn't a real class name, use your actual class name here that you want to listen to the World Variable.

At the bottom of the UpdateValueInt method, added this:

foreach (var yourListener in YourScriptListener)
{
  yourListener.NotifyOfWorldVariableChange(newValue);
}


This means you would need to have a method called NotifyOfWorldVariableChange in your real class name. Hope that helps.

Here's the full code in context.

using UnityEngine;
using System.Text;

using UnityEngine.UI;

namespace DarkTonic.CoreGameKit {
   [RequireComponent(typeof(Text))]
   [AddComponentMenu("Dark Tonic/Core GameKit/Listeners/World Variable Listener")]
   // ReSharper disable once CheckNamespace
   /// <summary>
   /// This class is used to listen to key events for a World Variable.
   /// </summary>
   public class WorldVariableListener : MonoBehaviour {
       public YourScriptListener[] YourScriptListeners;

       // ReSharper disable InconsistentNaming
       /*! \cond PRIVATE */
       public string variableName = "";
       public WorldVariableTracker.VariableType vType = WorldVariableTracker.VariableType._integer;
       public bool displayVariableName = false;
       public int decimalPlaces = 1;
       public bool useCommaFormatting = true;
       public bool useFixedNumberOfDigits;
       public int fixedDigitCount = 8;
       // ReSharper restore InconsistentNaming
       /*! \endcond */

       private int _variableValue;
       private float _variableFloatValue;

       private Text _text;

       // ReSharper disable once UnusedMember.Local
       void Awake() {
           _text = GetComponent<Text>();
       }

       void OnEnable() {
           WorldVariableTracker.UpdateAllListeners();
       }

       /// <summary>
       /// This Gets called when the integer World Variable's value changes.
       /// </summary>
       /// <param name="newValue">new value</param>
       /// <param name="oldVal">old value</param>
       public virtual void UpdateValue(int newValue, int oldVal) {
           _variableValue = newValue;
           var valFormatted = new StringBuilder(string.Format("{0}{1}", displayVariableName ? variableName + ": " : "", _variableValue.ToString("N0")));

           if (!useCommaFormatting) {
               valFormatted = valFormatted.Replace(",", "");
           }

           if (_text == null || !SpawnUtility.IsActive(_text.gameObject)) {
               return;
           }

           if (useFixedNumberOfDigits) {
               while (valFormatted.Length < fixedDigitCount) {
                   valFormatted.Insert(0, "0");
               }
           }

           _text.text = valFormatted.ToString();
           
           foreach (var yourListener in YourScriptListener)
           {
               yourListener.NotifyOfWorldVariableChange(newValue);
           }
       }
   }
}


No problem.

The Textbox is only used by the main Listener. If you don't need it, you can remove it. You're free to put whatever code you like in your other Listener classes that notify the main Listener.

That's actually on the roadmap to have a Listener without UI required. For now, just comment out the Required attribute and have at it.