Add List and ListItem views.

Part of #25.

Sources/Slipstream/Documentation.docc/W3C/W3CViews.md

@@ -36,6 +36,8 @@ The complete W3C HTML elements standard can be found [here](https://html.spec.wh
 - ``Paragraph``
 - ``Divider``
 - ``Blockquote``
+- ``List``
+- ``ListItem``
 - ``Div``
 
 ### Text-level semantics

Sources/Slipstream/W3C/Elements/GroupingContent/List.swift

@@ -0,0 +1,42 @@
+/// A view that represents a list of items.
+///
+/// The items can be ordered, where changing the order would
+/// change the meaning of the document, or unordered, where
+/// the order of the items is not important.
+///
+/// Lists are unordered by default.
+///
+/// ```swift
+/// struct MySiteContent: View {
+///   var body: some View {
+///     Body {
+///       List {
+///         ListItem {
+///           Text("Item 1")
+///         }
+///       }
+///     }
+///   }
+/// }
+/// ```
+///
+/// - SeeAlso: W3C [`ol`](https://html.spec.whatwg.org/multipage/grouping-content.html#the-ol-element) specification.
+/// - SeeAlso: W3C [`ul`](https://html.spec.whatwg.org/multipage/grouping-content.html#the-ul-element) specification.
+///
+/// ## See Also
+///
+/// - ``ListItem``
+public struct List<Content>: W3CElement where Content: View {
+  @_documentation(visibility: private)
+  public var tagName: String { ordered ? "ol" : "ul" }
+
+  /// Creates a list.
+  public init(ordered: Bool = false, @ViewBuilder content: @escaping () -> Content) {
+    self.ordered = ordered
+    self.content = content
+  }
+
+  @_documentation(visibility: private)
+  @ViewBuilder public let content: () -> Content
+  private let ordered: Bool
+}

Sources/Slipstream/W3C/Elements/GroupingContent/Listitem.swift

@@ -0,0 +1,33 @@
+/// A view that represents a list item.
+///
+/// ```swift
+/// struct MySiteContent: View {
+///   var body: some View {
+///     Body {
+///       List {
+///         ListItem {
+///           Text("Item 1")
+///         }
+///       }
+///     }
+///   }
+/// }
+/// ```
+///
+/// - SeeAlso: W3C [`li`](https://html.spec.whatwg.org/multipage/grouping-content.html#the-li-element) specification.
+///
+/// ## See Also
+///
+/// - ``List``
+public struct ListItem<Content>: W3CElement where Content: View {
+  @_documentation(visibility: private)
+  public let tagName: String = "li"
+
+  /// Creates a list item.
+  public init(@ViewBuilder content: @escaping () -> Content) {
+    self.content = content
+  }
+
+  @_documentation(visibility: private)
+  @ViewBuilder public let content: () -> Content
+}

Tests/SlipstreamTests/W3C/ListTests.swift

@@ -0,0 +1,39 @@
+import Testing
+
+import Slipstream
+
+struct ListTests {
+  @Test func emptyBlock() throws {
+    try #expect(renderHTML(List {}) == "<ul></ul>")
+    try #expect(renderHTML(List(ordered: true) {}) == "<ol></ol>")
+  }
+
+  @Test func withItems() throws {
+    try #expect(renderHTML(List {
+      ListItem {
+        Text("Item 1")
+      }
+      ListItem {
+        Text("Item 2")
+      }
+    }) == """
+<ul>
+ <li>Item 1</li>
+ <li>Item 2</li>
+</ul>
+""")
+    try #expect(renderHTML(List(ordered: true) {
+      ListItem {
+        Text("Item 1")
+      }
+      ListItem {
+        Text("Item 2")
+      }
+    }) == """
+<ol>
+ <li>Item 1</li>
+ <li>Item 2</li>
+</ol>
+""")
+  }
+}