Result Builders (#19)

Closes #6.

Author: davdroman

Demo/Demo/AppState.swift

@@ -3,6 +3,7 @@ import NavigationTransitions
 
 final class AppState: ObservableObject {
     enum Transition: CaseIterable, CustomStringConvertible, Hashable {
+        case `default`
         case slide
         case crossFade
         case slideAndFade
@@ -11,29 +12,33 @@ final class AppState: ObservableObject {
 
         var description: String {
             switch self {
+            case .default:
+                return "Default"
             case .slide:
                 return "Slide"
             case .crossFade:
                 return "Fade"
             case .slideAndFade:
                 return "Slide + Fade"
             case .moveVertically:
-                return "Move Vertically"
+                return "Slide Vertically"
             case .swing:
                 return "Swing"
             }
         }
 
-        func callAsFunction() -> NavigationTransition {
+        func callAsFunction() -> AnyNavigationTransition {
             switch self {
+            case .default:
+                return .default
             case .slide:
                 return .slide
             case .crossFade:
                 return .fade(.cross)
             case .slideAndFade:
                 return .slide.combined(with: .fade(.in))
             case .moveVertically:
-                return .move(axis: .vertical)
+                return .slide(axis: .vertical)
             case .swing:
                 return .swing
             }
@@ -89,7 +94,7 @@ final class AppState: ObservableObject {
         var curve: Curve
         var duration: Duration
 
-        func callAsFunction() -> NavigationTransition.Animation {
+        func callAsFunction() -> AnyNavigationTransition.Animation {
             switch curve {
             case .linear:
                 return .linear(duration: duration())
@@ -117,7 +122,7 @@ final class AppState: ObservableObject {
             }
         }
 
-        func callAsFunction() -> NavigationTransition.Interactivity {
+        func callAsFunction() -> AnyNavigationTransition.Interactivity {
             switch self {
             case .disabled:
                 return .disabled
@@ -130,7 +135,7 @@ final class AppState: ObservableObject {
     }
 
     @Published var transition: Transition = .slide
-    @Published var animation: Animation = .init(curve: .easeInOut, duration: .medium)
+    @Published var animation: Animation = .init(curve: .easeInOut, duration: .fast)
     @Published var interactivity: Interactivity = .edgePan
 
     @Published var isPresentingSettings: Bool = false

Demo/Demo/Swing.swift

@@ -1,24 +1,44 @@
 import NavigationTransition
 import SwiftUI
 
-extension NavigationTransition {
+extension AnyNavigationTransition {
     static var swing: Self {
+        .init(Swing())
+    }
+}
+
+struct Swing: NavigationTransition {
+    var body: some NavigationTransition {
         let angle = Angle(degrees: 70)
         let offset: CGFloat = 150
         let scale: CGFloat = 0.5
 
-        return .move(axis: .horizontal).combined(
-            with: .asymmetric(
-                push: .asymmetric(
-                    insertion: [.rotate(-angle), .offset(x: offset), .opacity, .scale(scale)].combined(),
-                    removal: [.rotate(angle), .offset(x: -offset)].combined()
-                ),
-                pop: .asymmetric(
-                    insertion: [.rotate(angle), .offset(x: -offset), .opacity, .scale(scale), .bringToFront].combined(),
-                    removal: [.rotate(-angle), .offset(x: offset)].combined()
-                )
-            )
-        )
+        Slide(axis: .horizontal)
+        OnPush {
+            OnInsertion {
+                Rotate(-angle)
+                Offset(x: offset)
+                Opacity()
+                Scale(scale)
+            }
+            OnRemoval {
+                Rotate(angle)
+                Offset(x: -offset)
+            }
+        }
+        OnPop {
+            OnInsertion {
+                Rotate(angle)
+                Offset(x: -offset)
+                Opacity()
+                Scale(scale)
+                BringToFront()
+            }
+            OnRemoval {
+                Rotate(-angle)
+                Offset(x: offset)
+            }
+        }
     }
 }