feat: Adds extension to argument parser's command configuration

Sources/CliDocCore/Nodes/LabeledContent.swift

@@ -0,0 +1,114 @@
+/// A text node that consists of a label and content.
+///
+///
+public struct LabeledContent<Label: TextNode, Content: TextNode>: TextNode {
+
+  @usableFromInline
+  let label: Label
+
+  @usableFromInline
+  let content: Content
+
+  @inlinable
+  public init(
+    @TextBuilder _ content: () -> Content,
+    @TextBuilder label: () -> Label
+  ) {
+    self.label = label()
+    self.content = content()
+  }
+
+  @inlinable
+  public var body: some TextNode {
+    style(.default)
+  }
+}
+
+public extension LabeledContent {
+
+  /// Apply the given style to the labeled content.
+  ///
+  /// - Parameters:
+  ///   - style: The labeled content style to apply.
+  @inlinable
+  func style<S: LabeledContentStyle>(_ style: S) -> some TextNode {
+    style.render(content: .init(label: label, content: content))
+  }
+}
+
+/// Holds the type-erased label and content of a ``LabeledContent`` text node.
+///
+/// This is used when creating custom styles for the ``LabeledContent``.
+///
+public struct LabeledContentConfiguration {
+
+  /// The type-erased label text node.
+  public let label: any TextNode
+
+  /// The type-erased content text node.
+  public let content: any TextNode
+
+  @usableFromInline
+  init(label: any TextNode, content: any TextNode) {
+    self.label = label
+    self.content = content
+  }
+}
+
+public protocol LabeledContentStyle: TextModifier where Content == LabeledContentConfiguration {}
+
+public extension LabeledContentStyle where Self == HorizontalLabeledContentStyle {
+
+  static var `default`: Self {
+    horizontal()
+  }
+
+  @inlinable
+  static func horizontal(separator: Separator.Horizontal = .space()) -> Self {
+    HorizontalLabeledContentStyle(separator: separator)
+  }
+}
+
+public extension LabeledContentStyle where Self == VerticalLabeledContentStyle {
+
+  @inlinable
+  static func vertical(separator: Separator.Vertical = .newLine()) -> Self {
+    VerticalLabeledContentStyle(separator: separator)
+  }
+}
+
+public struct HorizontalLabeledContentStyle: LabeledContentStyle {
+
+  @usableFromInline
+  let separator: Separator.Horizontal
+
+  @usableFromInline
+  init(separator: Separator.Horizontal) {
+    self.separator = separator
+  }
+
+  public func render(content: LabeledContentConfiguration) -> some TextNode {
+    HStack(separator: separator) {
+      content.label
+      content.content
+    }
+  }
+}
+
+public struct VerticalLabeledContentStyle: LabeledContentStyle {
+
+  @usableFromInline
+  let separator: Separator.Vertical
+
+  @usableFromInline
+  init(separator: Separator.Vertical) {
+    self.separator = separator
+  }
+
+  public func render(content: LabeledContentConfiguration) -> some TextNode {
+    VStack(separator: separator) {
+      content.label
+      content.content
+    }
+  }
+}