Port documentation from JoinedText library

Sources/TextBuilder/TextBuilder.swift

@@ -1,5 +1,24 @@
 import SwiftUI
 
+/// A custom attribute that constructs combined text views.
+///
+/// You can use ``TextBuilder`` as an attribute for text-producing properties
+/// or function parameters, allowing them to provide combined text views. For example,
+/// the following `loremIpsum` property will create a single styled text view with each
+/// text separated using eggplant emoji.
+///
+///     struct EggplantSeparator: TextBuilderSeparator {
+///         static var separator: String { " 🍆 " }
+///     }
+///
+///     @TextBuilder<EggplantSeparator>
+///     var loremIpsum: Text {
+///         Text("Lorem").underline().foregroundColor(.blue)
+///         Text("ipsum dolor")
+///         Text("sit").bold()
+///         Text("amet, consectetur")
+///     }
+///
 @resultBuilder
 public struct TextBuilder<Separator: TextBuilderSeparator> {
     public static func buildArray(_ texts: [[Text]]) -> [Text] {

Sources/TextBuilder/TextExtensions.swift

@@ -5,6 +5,19 @@ extension StringProtocol {
 }
 
 extension Sequence where Element == Text {
+
+    /// Returns a new `Text` by concatenating the elements of the sequence,
+    ///
+    /// The following example shows how an array of `Text` views can be joined to a
+    /// single `Text` view with comma-separated string:
+    ///
+    ///     let cast = [Text("Vivien"), Text("Marlon"), Text("Kim")]
+    ///     let list = cast.joined(separator: Text(", "))
+    ///     // Gives Text("Vivien, Marlon, Kim")
+    ///
+    /// - Parameter separator: A `Text` view to insert between each of the elements
+    ///   in this sequence. By default there is no separator.
+    /// - Returns: A single, concatenated `Text` view.
     public func joined(separator: Text = Text("")) -> Text {
         var isInitial = true
         return reduce(Text("")) { (result, text) in
@@ -18,10 +31,24 @@ extension Sequence where Element == Text {
 }
 
 extension Text {
+
+    /// Creates a  combined text view based on the given `content` by inserting
+    /// `separator` text views between each received text component.
+    ///
+    /// - Parameters:
+    ///   - separator: The text to use as a separator between received text components.
+    ///     By default there is no separator.
+    ///   - content: A text builder that creates text components.
     public init(separator: Text = Text(""), @BasicTextBuilder content: () -> [Text]) {
         self = content().joined(separator: separator)
     }
 
+    /// Creates a  combined text view based on the given `content` by inserting
+    /// `separator` string between each received text component.
+    ///
+    /// - Parameters:
+    ///   - separator: The string to use as a separator between received text components.
+    ///   - content: A text builder that creates text components.
     public init<Separator: StringProtocol>(separator: Separator, @BasicTextBuilder content: () -> [Text]) {
         self.init(separator: Text(separator), content: content)
     }