add a way to construct device trees declaratively and conditionally

src/plugins/TreeConstructor.hpp

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <functional>
+#include <Tree.hpp>
+
+// Allows declarative and conditional tree construction
+// More precisely, TreeConstructor a b -> TreeNode b, where there is a function a -> [b]
+template <typename In, typename Out> struct TreeConstructor {
+	std::function<std::vector<Out>(In)> nodesToAttach;
+	std::vector<TreeConstructor<In, Out>> children;
+};
+
+template <typename In, typename Out>
+void constructTree(TreeConstructor<In, Out> consNode, TuxClocker::TreeNode<Out> &node, In in) {
+	for (auto &newNode : consNode.nodesToAttach(in)) {
+		// Attach wanted child
+		auto treeNode = TuxClocker::TreeNode<Out>{newNode};
+		node.appendChild(treeNode);
+		for (auto &child : consNode.children)
+			// We need pointer since node.children() just gives a copy
+			constructTree(child, node.childrenPtr()->back(), in);
+	}
+}