feat: Working on node builder

Sources/CliDoc/NodeBuilder.swift

@@ -16,16 +16,16 @@ public enum NodeBuilder {
     .init(components, separator: .empty())
   }
 
-  public static func buildEither<N0: NodeRepresentable, N1: NodeRepresentable>(
-    first component: N0
-  ) -> _ConditionalNode<N0, N1> {
-    .first(component)
+  public static func buildEither<N: NodeRepresentable>(
+    first component: N
+  ) -> N {
+    component
   }
 
-  public static func buildEither<N0: NodeRepresentable, N1: NodeRepresentable>(
-    second component: N1
-  ) -> _ConditionalNode<N0, N1> {
-    .second(component)
+  public static func buildEither<N: NodeRepresentable>(
+    second component: N
+  ) -> N {
+    component
   }
 
   public static func buildBlock<N: NodeRepresentable>(_ components: N...) -> _ManyNode {
@@ -37,8 +37,13 @@ public enum NodeBuilder {
 //     expression.eraseToAnyNode()
 //   }
 
-  public static func buildOptional<N: NodeRepresentable>(_ component: N?) -> AnyNode {
-    component?.eraseToAnyNode() ?? AnyNode { Text.empty() }
+  public static func buildOptional<N: NodeRepresentable>(_ component: N?) -> _ConditionalNode<N, Text> {
+    switch component {
+    case let .some(node):
+      return .first(node)
+    case .none:
+      return .second(.empty())
+    }
   }
 
   public static func buildFinalResult<N: NodeRepresentable>(_ component: N) -> N {
@@ -79,15 +84,18 @@ public struct _ManyNode: NodeRepresentable {
   @usableFromInline
   init(
     _ nodes: [any NodeRepresentable],
-    separator: AnyNode = Text.empty().eraseToAnyNode()
+    separator: any NodeRepresentable = "\n" as any NodeRepresentable
   ) {
-    self.nodes = nodes
-    self.separator = separator
-  }
-
-  @inlinable
-  public init(_ nodes: [any NodeRepresentable], separator: any NodeRepresentable) {
-    self.nodes = nodes
+    // Flatten the nodes.
+    var allNodes = [any NodeRepresentable]()
+    for node in nodes {
+      if let many = node as? Self {
+        allNodes += many.nodes
+      } else {
+        allNodes.append(node)
+      }
+    }
+    self.nodes = allNodes
     self.separator = separator
   }