Merge pull request #6 from hugehoge/add-doc-comment

Added document comment

Sources/Public/ScrollView+SnappableModifier.swift

@@ -1,6 +1,11 @@
 import SwiftUI
 
 public extension ScrollView {
+  /// Make the ScrollView snappable.
+  /// - Parameters:
+  ///   - alignment: Alignment that is used as a guide for snapping.
+  ///   - mode: The mode by when ScrollView snaps the items.
+  /// - Returns: A ScrollView, with the snapping behavior set.
   func snappable(
     _ alignment: SnapAlignment = .center,
     mode: SnapMode = .afterScrolling

Sources/Public/Types/DecelerationRate.swift

@@ -1,3 +1,4 @@
 import UIKit
 
+/// A typealias defining the deceleration rate for ScrollView that be applied `snappable` modifier.
 public typealias DecelerationRate = UIScrollView.DecelerationRate

Sources/Public/Types/SnapAlignment.swift

@@ -1,15 +1,25 @@
+/// An alignment definition in snapping.
 public enum SnapAlignment {
+  /// A snap guide marking the top and leading edges of the view.
   @available(*, unavailable, message: "Not yet to support in horizontal + vertical movements.")
   case topLeading
+  /// A snap guide marking the top edge of the view.
   case top
+  /// A snap guide marking the top and trailing edges of the view.
   @available(*, unavailable, message: "Not yet to support in horizontal + vertical movements.")
   case topTrailing
+  /// A snap guide marking the leading edge of the view.
   case leading
+  /// A snap guide marking the center of the view.
   case center
+  /// A snap guide marking the trailing edge of the view.
   case trailing
+  /// A snap guide marking the bottom and leading edges of the view.
   @available(*, unavailable, message: "Not yet to support in horizontal + vertical movements.")
   case bottomLeading
+  /// A snap guide marking the bottom edge of the view.
   case bottom
+  /// A snap guide marking the bottom and trailing edges of the view.
   @available(*, unavailable, message: "Not yet to support in horizontal + vertical movements.")
   case bottomTrailing
 }

Sources/Public/Types/SnapMode.swift

@@ -1,15 +1,30 @@
 import UIKit
 
+/// The modes that the snapping behavior of ScrollView.
+///
+/// It has the following two setting values depending on the snap timing.
+/// - `.immediately`
+/// - `.afterScrolling`
 public struct SnapMode {
+  /// The default setting for snapping after scrolling.
   public static let afterScrolling: SnapMode = afterScrolling(decelerationRate: .fast)
+  /// The default setting for snapping immediately.
   public static let immediately: SnapMode = immediately(decelerationRate: .normal, withFlick: true)
 
   internal let decelerationRate: DecelerationRate
   internal let snapTiming: SnapTiming
 
+  /// An editable setting for snapping after scrolling.
+  /// - Parameter decelerationRate: The deceleration rate of the ScrollView after dragging end.
+  /// - Returns: SnapMode, edited as afterScrolling.
   public static func afterScrolling(decelerationRate: DecelerationRate) -> SnapMode {
     SnapMode(decelerationRate: decelerationRate, snapTiming: .afterScrolling)
   }
+  /// An editable setting for snapping immediately.
+  /// - Parameters:
+  ///   - decelerationRate: The deceleration rate of the ScrollView after dragging end.
+  ///   - withFlick: The flag whether or not do snapping in consideration of flicking.
+  /// - Returns: SnapMode, edited as immediately.
   public static func immediately(decelerationRate: DecelerationRate, withFlick: Bool = true) -> SnapMode {
     SnapMode(decelerationRate: decelerationRate, snapTiming: .immediately(withFlick: withFlick))
   }

Sources/Public/View+SnappableIDModifier.swift

@@ -1,6 +1,13 @@
 import SwiftUI
 
 public extension View {
+  /// Make the View a snap target.
+  ///
+  /// `snapID(_:)` applies [id(\_:)](https://developer.apple.com/documentation/swiftui/view/id(_:))
+  /// modifier internally. Therefore, there is no need to apply `id(_:)` modifier additionally, and if you do, it will happen
+  /// an unexpected behavior of snapping.
+  ///
+  /// - Returns: A View, set as a snap target.
   func snapID<ID>(_ id: ID) -> some View where ID: Hashable {
     self.modifier(SnapIDModifier(id: id))
   }