Add the intial attributes.

Tsu.Trees.RedGreen/src/ChildAttribute.cs

@@ -0,0 +1,16 @@
+namespace Tsu.Trees.RedGreen;
+
+/// <summary>
+/// Indicates this field/property stores a child node.
+/// </summary>
+/// <remarks>
+/// This is used in generation of GetChildren and GetSlot.
+/// </remarks>
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, Inherited = false, AllowMultiple = false)]
+public sealed class ChildAttribute : Attribute
+{
+    /// <summary>
+    /// The override for the slot of this child.
+    /// </summary>
+    public int? Slot { get; }
+}

Tsu.Trees.RedGreen/src/GreenNodeKindAttribute.cs

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+namespace Tsu.Trees.RedGreen;
+
+/// <summary>
+/// Overrides the kind for a given green node.
+/// </summary>
+/// <param name="kind">
+/// The value of the kind this node should have.
+/// This should be the value on the enum (e.g.: SyntaxKind.ClassDeclarationSyntax)
+/// </param>
+[AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)]
+public sealed class GreenNodeKindAttribute(object kind) : Attribute
+{
+    /// <summary>
+    /// This node's Kind.
+    /// </summary>
+    public object Kind { get; } = kind;
+}

Tsu.Trees.RedGreen/src/GreenNodeRoot.cs

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+namespace Tsu.Trees.RedGreen;
+
+/// <summary>
+/// An attribute that marks the given class as the base class for all nodes in a green node tree.
+/// </summary>
+[AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)]
+public sealed class GreenNodeRootAttribute(string listName, Type redRoot) : Attribute
+{
+    /// <summary>
+    /// The name of the list type for this green tree.
+    /// </summary>
+    public string ListName { get; } = listName;
+
+    /// <summary>
+    /// The base node type for all nodes in the red tree.
+    /// </summary>
+    public Type RedBase { get; } = redRoot;
+
+    /// <summary>
+    /// The enum type that contains the definitions for the node kinds.
+    /// </summary>
+    public Type? KindEnum { get; set; }
+
+    // NOTE: Make cache configurable?
+    // /// <summary>
+    // /// Whether to enable the green cache or not.
+    // /// </summary>
+    // public bool CacheEnabled { get; set; } = true;
+
+    // /// <summary>
+    // /// The amount of bits from the hash to use for caching.
+    // /// </summary>
+    // public int CacheSizeBits { get; set; } = 16;
+}