feat: new ValueProvider improvements and source generator.

addons/AetherBind/ValueProvider.cs

@@ -3,13 +3,14 @@ using System;
 namespace GodotHostTest.AetherBind;
 
 /// <summary>
-///     An object that allows communication through scopes, by providing a couple getter/setter that can be injected in
-///     different scopes.
+///     An object that allows communication through scopes (or inside the scope itself) by providing a couple getter/setter that can be injected in different scopes (or the same scope).
 /// </summary>
 /// <typeparam name="T">The type that's been passed through scopes.</typeparam>
-/// <seealso cref="BuilderExtensions.AddValueProvider" />
+/// <seealso cref="BuilderExtensions.AddValueProvider{TValueType,TScope}" />
+/// <seealso cref="BuilderExtensions.AddValueProvider{TValueType,TSourceScope,TDestinationScope}" />
 public class ValueProvider<T>
 {
+    private IValueGetter<T>? _getter;
     private bool _isSet;
     private T? _value;
 
@@ -20,9 +21,16 @@ public class ValueProvider<T>
 
     public IValueSetter<T> Setter { get; }
 
-    public IValueGetter<T> Getter => !_isSet
-        ? throw new InvalidOperationException($"Value of type {typeof(T)} has not been set yet.")
-        : new GetterImplementation(_value!);
+    public IValueGetter<T> Getter
+    {
+        get
+        {
+            _getter ??= !_isSet
+                ? throw new InvalidOperationException($"Value of type {typeof(T)} has not been set yet.")
+                : new GetterImplementation(_value!);
+            return _getter;
+        }
+    }
 
     private class SetterImplementation(ValueProvider<T> valueProvider) : IValueSetter<T>
     {