Add @ViewBuilder to ForEachStore and IfLetStore (#501)

* Add @ViewBuilder to ForEachStore and IfLetStore

* Update IfLetStore else branch to take view builder

Author: stephencelis

Examples/CaseStudies/SwiftUICaseStudies/01-GettingStarted-OptionalState.swift

@@ -69,7 +69,9 @@ struct OptionalBasicsView: View {
                   .buttonStyle(BorderlessButtonStyle())
               }
             },
-            else: Text(template: "`CounterState` is `nil`", .body)
+            else: {
+              Text(template: "`CounterState` is `nil`", .body)
+            }
           )
         }
       }

Examples/CaseStudies/SwiftUICaseStudies/03-Navigation-Lists-NavigateAndLoad.swift

@@ -89,7 +89,7 @@ struct NavigateAndLoadListView: View {
                 self.store.scope(
                   state: { $0.selection?.value }, action: NavigateAndLoadListAction.counter),
                 then: CounterView.init(store:),
-                else: ActivityIndicator()
+                else: { ActivityIndicator() }
               ),
               tag: row.id,
               selection: viewStore.binding(

Examples/CaseStudies/SwiftUICaseStudies/03-Navigation-NavigateAndLoad.swift

@@ -71,7 +71,7 @@ struct NavigateAndLoadView: View {
               self.store.scope(
                 state: { $0.optionalCounter }, action: NavigateAndLoadAction.optionalCounter),
               then: CounterView.init(store:),
-              else: ActivityIndicator()
+              else: { ActivityIndicator() }
             ),
             isActive: viewStore.binding(
               get: { $0.isNavigationActive },

Examples/CaseStudies/SwiftUICaseStudies/03-Navigation-Sheet-PresentAndLoad.swift

@@ -79,7 +79,7 @@ struct PresentAndLoadView: View {
           self.store.scope(
             state: { $0.optionalCounter }, action: PresentAndLoadAction.optionalCounter),
           then: CounterView.init(store:),
-          else: ActivityIndicator()
+          else: { ActivityIndicator() }
         )
       }
       .navigationBarTitle("Present and load")

Examples/CaseStudies/UIKitCaseStudies/Internal/IfLetStoreController.swift

@@ -22,7 +22,7 @@ final class IfLetStoreController<State, Action>: UIViewController {
   init(
     store: Store<State?, Action>,
     then ifDestination: @escaping (Store<State, Action>) -> UIViewController,
-    else elseDestination: @autoclosure @escaping () -> UIViewController
+    else elseDestination: @escaping () -> UIViewController
   ) {
     self.store = store
     self.ifDestination = ifDestination

Examples/CaseStudies/UIKitCaseStudies/NavigateAndLoad.swift

@@ -90,7 +90,7 @@ class EagerNavigationViewController: UIViewController {
             store: self.store
               .scope(state: { $0.optionalCounter }, action: EagerNavigationAction.optionalCounter),
             then: CounterViewController.init(store:),
-            else: ActivityIndicatorViewController()
+            else: ActivityIndicatorViewController.init
           ),
           animated: true
         )

Sources/ComposableArchitecture/Internal/Deprecations.swift

@@ -1,6 +1,19 @@
 import Combine
 import SwiftUI
 
+// NB: Deprecated after 0.17.0:
+
+extension IfLetStore {
+  @available(*, deprecated, message: "'else' now takes a view builder closure")
+  public init<IfContent, ElseContent>(
+    _ store: Store<State?, Action>,
+    @ViewBuilder then ifContent: @escaping (Store<State, Action>) -> IfContent,
+    else elseContent: @escaping @autoclosure () -> ElseContent
+  ) where Content == _ConditionalContent<IfContent, ElseContent> {
+    self.init(store, then: ifContent, else: elseContent)
+  }
+}
+
 // NB: Deprecated after 0.13.0:
 
 @available(*, deprecated, renamed: "BindingAction")

Sources/ComposableArchitecture/SwiftUI/ForEachStore.swift

@@ -71,7 +71,7 @@ where Data: Collection, ID: Hashable, Content: View {
   public init<EachContent>(
     _ store: Store<Data, (Data.Index, EachAction)>,
     id: KeyPath<EachState, ID>,
-    content: @escaping (Store<EachState, EachAction>) -> EachContent
+    @ViewBuilder content: @escaping (Store<EachState, EachAction>) -> EachContent
   )
   where
     Data == [EachState],
@@ -104,7 +104,7 @@ where Data: Collection, ID: Hashable, Content: View {
   ///   - content: A function that can generate content given a store of an element.
   public init<EachContent>(
     _ store: Store<Data, (Data.Index, EachAction)>,
-    content: @escaping (Store<EachState, EachAction>) -> EachContent
+    @ViewBuilder content: @escaping (Store<EachState, EachAction>) -> EachContent
   )
   where
     Data == [EachState],
@@ -126,7 +126,7 @@ where Data: Collection, ID: Hashable, Content: View {
   ///   - content: A function that can generate content given a store of an element.
   public init<EachContent: View>(
     _ store: Store<IdentifiedArray<ID, EachState>, (ID, EachAction)>,
-    content: @escaping (Store<EachState, EachAction>) -> EachContent
+    @ViewBuilder content: @escaping (Store<EachState, EachAction>) -> EachContent
   )
   where
     EachContent: View,

Sources/ComposableArchitecture/SwiftUI/IfLetStore.swift

@@ -10,7 +10,7 @@ import SwiftUI
 ///     IfLetStore(
 ///       store.scope(state: \SearchState.results, action: SearchAction.results),
 ///       then: SearchResultsView.init(store:),
-///       else: Text("Loading search results...")
+///       else: { Text("Loading search results...") }
 ///     )
 ///
 ///  And for performing navigation when a piece of state becomes non-`nil`:
@@ -42,8 +42,8 @@ public struct IfLetStore<State, Action, Content>: View where Content: View {
   ///   - elseContent: A view that is only visible when the optional state is `nil`.
   public init<IfContent, ElseContent>(
     _ store: Store<State?, Action>,
-    then ifContent: @escaping (Store<State, Action>) -> IfContent,
-    else elseContent: @escaping @autoclosure () -> ElseContent
+    @ViewBuilder then ifContent: @escaping (Store<State, Action>) -> IfContent,
+    @ViewBuilder else elseContent: @escaping () -> ElseContent
   ) where Content == _ConditionalContent<IfContent, ElseContent> {
     self.store = store
     self.content = { viewStore in
@@ -64,7 +64,7 @@ public struct IfLetStore<State, Action, Content>: View where Content: View {
   ///     is visible only when the optional state is non-`nil`.
   public init<IfContent>(
     _ store: Store<State?, Action>,
-    then ifContent: @escaping (Store<State, Action>) -> IfContent
+    @ViewBuilder then ifContent: @escaping (Store<State, Action>) -> IfContent
   ) where Content == IfContent? {
     self.store = store
     self.content = { viewStore in