1 files changed, 248 insertions, 0 deletions
diff --git a/modules/core/tree.h b/modules/core/tree.h
new file mode 100644
index 0000000..68fa20a
--- /dev/null
+++ b/modules/core/tree.h
@@ -0,0 +1,248 @@
+#pragma once
+
+#include <variant>
+#include <vector>
+
+#include "error.h"
+
+namespace saw {
+/**
+ * Container with a simplistic approach to a branch
+ */
+template<typename T, typename Tree>
+class branch;
+
+/**
+ * Tree object holding branches.
+ *
+ * The name comes from the fact a tree is acting as a node while the branch class is the
+ * edge to a leaf or other nodes. A tree holds the branches while the branch either has
+ * a leaf or another sub tree.
+ */
+template<typename T, typename Tree>
+class tree_container final {
+private:
+	/**
+	 * Object holding the treeed branch instances
+	 */
+	std::vector<branch<T,Tree>> children_;
+public:
+	/**
+	 * Default constructor
+	 */
+	tree_container() = default;
+
+	/**
+	 * Destructor
+	 */
+	~tree_container() = default;
+
+	SAW_FORBID_COPY(tree_container);
+	SAW_DEFAULT_MOVE(tree_container);
+
+	/**
+	 * Reserve space for siz elements
+	 */
+	error_or<void> reserve(std::size_t siz){
+		try{
+			children_.reserve(siz);
+		}catch(const std::exception& e){
+			(void) e;
+
+			return make_error<err::out_of_memory>();
+		}
+
+		return void_t{};
+	}
+
+	/**
+	 * Add a branch with a leaf attached to the tree
+	 */
+	error_or<std::size_t> add(T leaf) {
+		std::size_t index = size();
+		try {
+			/**
+			 * Technically we're adding a leaf on a branch
+			 */
+			children_.emplace_back(std::move(leaf));
+		}catch(const std::exception& e){
+			(void)e;
+
+			return make_error<err::critical>();
+		}
+
+		return index;
+	}
+
+	/**
+	 * Add a branch to the tree with a tree attached
+	 */
+	error_or<std::size_t> add() {
+		std::size_t index = size();
+		try {
+
+			children_.emplace_back(Tree{});
+		}catch(const std::exception& e){
+			(void)e;
+
+			return make_error<err::critical>();
+		}
+
+		return index;
+	}
+
+	/**
+	 * Returns the amount of branches contained within this tree level
+	 */
+	std::size_t size() const {
+		return children_.size();
+	}
+
+	/**
+	 * Returns the branch at i
+	 */
+	branch<T,Tree>& at(std::size_t i){
+		return children_.at(i);
+	}
+
+	/**
+	 * Returns the branch at i
+	 */
+	const branch<T,Tree>& at(std::size_t i) const {
+		return children_.at(i);
+	}
+};
+
+template<typename T, typename Tree>
+class branch final {
+private:
+	using type = std::variant<Tree,T>;
+	type tov_;
+
+	/**
+	 * We're friend classing the tree since it's way easier this way and the branch and tree
+	 * class are intertwined heavily anyway.
+	 */
+public:
+	/**
+	 * 
+	 */
+	branch():tov_{Tree{}}{}
+
+	branch(Tree nd):tov_{std::move(nd)}{}
+
+	branch(T val):tov_{std::move(val)}{}
+
+	SAW_FORBID_COPY(branch);
+	SAW_DEFAULT_MOVE(branch);
+
+	template<typename NT>
+	bool is() const {
+		return std::holds_alternative<NT>(tov_);
+	}
+
+	bool is_tree() const {
+		return std::holds_alternative<Tree>(tov_);
+	}
+
+	bool is_value() const {
+		return std::holds_alternative<T>(tov_);
+	}
+
+	template<typename NT>
+	NT& get() {
+		return std::get<NT>(tov_);
+	}
+	
+	template<typename NT>
+	const NT& get() const {
+		return std::get<NT>(tov_);
+	}
+
+	Tree& get_tree(){
+		return std::get<Tree>(tov_);
+	}
+
+	const Tree& get_tree() const {
+		return std::get<Tree>(tov_);
+	}
+
+	T& get_value(){
+		return std::get<T>(tov_);
+	}
+
+	const T& get_value() const {
+		return std::get<T>(tov_);
+	}
+
+	template<typename NT>
+	error_or<NT> extract(){
+		if(!is<NT>()){
+			return make_error<err::invalid_state>();
+		}
+		
+		NT nd = std::move(std::get<NT>(tov_));
+		tov_ = Tree{};
+
+		return nd;
+	}
+	
+	template<typename NT>
+	error_or<NT> replace(type nd){
+		auto eon = extract<NT>();
+		if(eon.is_error()){
+			return eon;
+		}
+
+		tov_ = std::move(nd);
+
+		return eon;
+	}
+
+	error_or<Tree> extract_tree() {
+		return extract<Tree>();
+	}
+
+	error_or<Tree> replace_tree(type nd){
+		return replace<Tree>(std::move(nd));
+	}
+
+	error_or<T> extract_value() {
+		return extract<T>();
+	}
+
+	error_or<T> replace_value(type nd){
+		return replace<T>(std::move(nd));
+	}
+};
+
+template<typename T>
+class tree {
+	private:
+		tree_container<T,tree<T>> data_;
+	public:
+		error_or<void> reserve(std::size_t size){
+			return data_.reserve(size);
+		}
+
+		size_t size() const {
+			return data_.size();
+		}
+
+		error_or<size_t> add() {
+			return data_.add();
+		}
+
+		error_or<size_t> add(T leaf){
+			return data_.add(std::move(leaf));
+		}
+
+		branch<T, tree<T>>& at(size_t i){
+			return data_.at(i);
+		}
+
+		const branch<T, tree<T>>& at(size_t i) const {
+			return data_.at(i);
+		}
+};
+}