Added docs (#2)

Author: NSFatalError

.spi.yml

@@ -0,0 +1,5 @@
+version: 1
+builder:
+  configs:
+    - documentation_targets:
+      - Publishable

Sources/Publishable/Documentation.docc/Publishable.md

@@ -0,0 +1,14 @@
+# ``Publishable-module``
+
+Observe changes to `Observable` types synchronously with `Combine`.
+
+## Topics
+
+### Making Types Publishable
+
+- ``Publishable()``
+- ``Publishable-protocol``
+
+### Getting Property Publishers
+
+- ``AnyPropertyPublisher``

Sources/Publishable/PropertyPublisher/AnyPropertyPublisher.swift

@@ -8,15 +8,24 @@
 
 import Combine
 
+/// An object that exposes `Combine` publishers for  ``willChange`` and ``didChange`` events.
+///
+/// Subclasses of this class are generated by the ``Publishable()`` macro,
+/// and provide publishers for all mutable instance properties of the type the macro is applied to.
+///
 open class AnyPropertyPublisher<Object: AnyObject> {
 
     private let _willChange = PassthroughSubject<Object, Never>()
     private let _didChange = PassthroughSubject<Object, Never>()
 
+    /// Emits the `Object` **before** any of its stored properties are assigned a new value.
+    ///
     public var willChange: AnyPublisher<Object, Never> {
         _willChange.eraseToAnyPublisher()
     }
 
+    /// Emits the `Object` **after** any of its stored properties are assigned a new value.
+    ///
     public var didChange: AnyPublisher<Object, Never> {
         _didChange.eraseToAnyPublisher()
     }

Sources/Publishable/PropertyPublisher/Publishable.swift

@@ -6,6 +6,22 @@
 //  Copyright © 2025 Kamil Strzelecki. All rights reserved.
 //
 
+import Observation
+
+/// A macro that adds ``Publishable-protocol`` conformance to `Observable` types.
+///
+/// - Note: This macro works only with `final` classes to which the `Observable` or `SwiftData.Model` macro has been applied directly.
+///
+/// The `Publishable` macro adds a new ``Publishable/publisher`` property to your type,
+/// which exposes `Combine` publishers for all mutable instance properties - both stored and computed.
+///
+/// If a property’s type conforms to `Equatable`, its publisher automatically removes duplicate values.
+/// Just like the `Published` property wrapper, subscribing to any of the exposed publishers immediately emits the current value.
+///
+/// - Important: Swift Macros do not have access to full type information of expressions used in the code they’re applied to.
+/// Since working with `Combine` requires knowledge of concrete types, this macro attempts to infer the types of properties when they are not explicitly specified.
+/// However, this inference may fail in non-trivial cases. If the generated code fails to compile, explicitly specifying the type of the affected property should resolve the issue.
+///
 @attached(
     member,
     names: named(_publisher),
@@ -22,9 +38,22 @@ public macro Publishable() = #externalMacro(
     type: "PublishableMacro"
 )
 
-public protocol Publishable: AnyObject {
+/// A type that can be observed using both the `Observation` and `Combine` frameworks.
+///
+/// You don't need to declare conformance to this protocol yourself.
+/// It is generated automatically when you apply the ``Publishable()`` macro to your type.
+///
+public protocol Publishable: AnyObject, Observable {
 
+    /// A subclass of ``AnyPropertyPublisher`` generated by the ``Publishable()`` macro,
+    /// containing publishers for all mutable instance properties of the type.
+    ///
     associatedtype PropertyPublisher: AnyPropertyPublisher<Self>
 
+    /// An instance that exposes `Combine` publishers for all mutable instance properties of the type.
+    ///
+    /// - Important: Don't store this instance in an external property. Accessing it after the original object has been deallocated
+    /// may result in a crash. Always access it directly through the object that exposes it.
+    ///
     var publisher: PropertyPublisher { get }
 }

Sources/Publishable/Registrars/PublishableObservationRegistrar.swift

@@ -8,6 +8,7 @@
 
 import Observation
 
+@_documentation(visibility: private)
 public protocol PublishableObservationRegistrar {
 
     associatedtype Object: Publishable, Observable

Sources/Publishable/Registrars/SwiftObservationRegistrar.swift

@@ -8,4 +8,5 @@
 
 import Observation
 
+@_documentation(visibility: private) // swiftformat:disable:next all
 public typealias SwiftObservationRegistrar = ObservationRegistrar