Add @FetchAll(sectionBy:)

Sources/SQLiteData/Documentation.docc/Articles/Fetching.md

@@ -145,6 +145,36 @@ This is a very efficient query that selects only the bare essentials of data tha
 needs to do its job. This kind of query is a lot more cumbersome to perform in SwiftData because
 you must construct a dedicated `FetchDescriptor` value and set its `propertiesToFetch`.
 
+It is also possible to group the results of a query into sections by providing a `sectionBy:` key
+path, similar to SwiftData's `@Query(sectionBy:)`. For example, given a `Reminder` table with a
+string `category` column:
+
+```swift
+@FetchAll(Reminder.order(by: \.category), sectionBy: \.category)
+var reminders
+```
+
+The flat results are still available from the property itself, and the projected value's
+``FetchAll/sections`` property groups them into a ``ResultsSectionCollection``, which is perfect
+for driving a sectioned list:
+
+```swift
+List {
+  ForEach($reminders.sections) { section in
+    Section(section.name) {
+      ForEach(section) { reminder in
+        Text(reminder.title)
+      }
+    }
+  }
+}
+```
+
+Results are grouped into a section for each distinct value at the key path. Sections are ordered
+by the position of their first element in the query's results, and elements within a section
+follow the query's order, so you can control the order of sections by ordering the query by the
+sectioned column.
+
 [sq-safe-sql-strings]: https://swiftpackageindex.com/pointfreeco/swift-structured-queries/~/documentation/structuredqueriescore/safesqlstrings
 [structured-queries-gh]: https://github.com/pointfreeco/swift-structured-queries
 [structured-queries-docs]: https://swiftpackageindex.com/pointfreeco/swift-structured-queries/main/documentation/structuredqueriescore/

Sources/SQLiteData/Documentation.docc/Extensions/FetchAll.md

@@ -10,6 +10,15 @@
 - ``init(wrappedValue:_:database:)``
 - ``load(_:database:)``
 
+### Sectioning data
+
+- ``init(wrappedValue:sectionBy:database:)``
+- ``init(wrappedValue:_:sectionBy:database:)``
+- ``load(_:sectionBy:database:)``
+- ``sections``
+- ``ResultsSectionCollection``
+- ``ResultsSection``
+
 ### Accessing state
 
 - ``wrappedValue``
@@ -21,7 +30,10 @@
 
 - ``init(wrappedValue:database:animation:)``
 - ``init(wrappedValue:_:database:animation:)``
+- ``init(wrappedValue:sectionBy:database:animation:)``
+- ``init(wrappedValue:_:sectionBy:database:animation:)``
 - ``load(_:database:animation:)``
+- ``load(_:sectionBy:database:animation:)``
 
 ### Combine integration
 
@@ -31,7 +43,10 @@
 
 - ``init(wrappedValue:database:scheduler:)``
 - ``init(wrappedValue:_:database:scheduler:)``
+- ``init(wrappedValue:sectionBy:database:scheduler:)``
+- ``init(wrappedValue:_:sectionBy:database:scheduler:)``
 - ``load(_:database:scheduler:)``
+- ``load(_:sectionBy:database:scheduler:)``
 
 ### Sharing infrastructure
 

Sources/SQLiteData/Fetch.swift

@@ -37,8 +37,8 @@ public struct Fetch<Value: Sendable>: Sendable {
       nonmutating set { state.wrappedValue.sharedReader = newValue }
     }
 
-    private let box: FetchBox<Value>
-    private let state: SwiftUI.State<FetchBox<Value>>
+    private let box: FetchBox<Value, Void>
+    private let state: SwiftUI.State<FetchBox<Value, Void>>
     private let generation = SwiftUI.State(wrappedValue: 0)
   #else
     /// The underlying shared reader powering the property wrapper.