Exploring new style

Sources/CliDoc2/Node.swift

@@ -0,0 +1,149 @@
+import Rainbow
+
+public protocol Node {
+  func render() -> String
+}
+
+extension String: Node {
+  public func render() -> String {
+    self
+  }
+}
+
+@resultBuilder
+enum NodeBuilder {
+
+  public static func buildPartialBlock<N: Node>(first: N) -> N {
+    first
+  }
+
+  static func buildPartialBlock<N0: Node, N1: Node>(accumulated: N0, next: N1) -> ManyNode {
+    .init(nodes: [accumulated, next])
+  }
+
+  public static func buildArray<N: Node>(_ components: [N]) -> ManyNode {
+    .init(nodes: components)
+  }
+
+  static func buildBlock<N: Node>(_ components: N...) -> ManyNode {
+    .init(nodes: components)
+  }
+
+  static func buildEither<N: Node>(first component: N) -> N {
+    component
+  }
+
+  static func buildEither<N: Node>(second component: N) -> N {
+    component
+  }
+
+  static func buildOptional<N: Node>(_ component: N?) -> any Node {
+    component
+  }
+
+}
+
+extension Optional: Node where Wrapped: Node {
+  public func render() -> String {
+    guard let node = self else { return "" }
+    return node.render()
+  }
+}
+
+struct ManyNode: Node {
+
+  var nodes: [any Node]
+
+  init(nodes: [any Node]) {
+    self.nodes = nodes.reduce(into: [any Node]()) { array, next in
+      if let many = next as? ManyNode {
+        array += many.nodes
+      } else {
+        array.append(next)
+      }
+    }
+  }
+
+  func render() -> String {
+    nodes.reduce("") { $0 + $1.render() }
+  }
+}
+
+struct Group: Node {
+  var content: [any Node]
+  var separator: any Node
+
+  init(
+    content: [any Node],
+    separator: any Node = "\n"
+  ) {
+    self.content = content
+    self.separator = separator
+  }
+
+  init(
+    separator: any Node = "\n",
+    @NodeBuilder content: () -> any Node
+  ) {
+    let content = content()
+    if let many = content as? ManyNode {
+      self.content = many.nodes
+    } else {
+      self.content = [content]
+    }
+    self.separator = separator
+  }
+
+  func render() -> String {
+    content.reduce("") {
+      $0 + $1.render() + separator.render()
+    }
+  }
+}
+
+struct ColorNode: Node {
+  let color: NamedColor
+  let node: any Node
+
+  func render() -> String {
+    node.render().applyingColor(color)
+  }
+}
+
+extension Node {
+  func color(_ color: NamedColor) -> some Node {
+    ColorNode(color: color, node: self)
+  }
+}
+
+struct Label: Node {
+  var node: any Node
+
+  init(@NodeBuilder _ content: () -> any Node) {
+    self.node = content()
+  }
+
+  func render() -> String {
+    node.render()
+  }
+}
+
+struct Note: Node {
+  var label: any Node
+  var content: any Node
+  var separator: any Node = " "
+
+  init(
+    separator: any Node = " ",
+    @NodeBuilder _ label: () -> any Node,
+    @NodeBuilder content: () -> any Node
+  ) {
+    self.separator = separator
+    self.label = label()
+    self.content = content()
+  }
+
+  func render() -> String {
+    Group(content: [label, content], separator: separator).render()
+  }
+}