Composite Generator

The Composite generator creates contract-first base types for tree-like object graphs. Generated code has no runtime dependency on PatternKit.

Usage

using PatternKit.Generators.Composite;

[CompositeComponent(GenerateTraversalHelpers = true)]
public partial interface ICategory
{
    string Name { get; }
}

public sealed class CategoryLeaf : CategoryComponentBase
{
    public override string Name { get; }
}

public sealed class CategoryNode : CategoryCompositeBase
{
    public override string Name { get; }
}

The generated component base defaults to leaf behavior: IsLeaf is true, Children is empty, and Add, Remove, and Clear throw NotSupportedException.

The generated composite base stores children in insertion order, rejects null children, exposes a read-only child view, and supports deterministic Add, Remove, and Clear.

Attributes

• [CompositeComponent] marks a partial interface or abstract class component contract.
• [CompositeIgnore] excludes a property or method from generated base declarations.

Diagnostics

• PKCMP001: component contract must be partial.
• PKCMP002: component target must be an interface or abstract class.
• PKCMP003: generated base type name conflicts with an existing type.
• PKCMP004: unsupported contract member, such as an event.