(FEAT): Began working on node implementations.

Drew out an inheritance map to review with the team.

lib/node.cpp

@@ -0,0 +1,21 @@
+#include "./node.h"
+
+#include <iostream>
+#include <memory>
+
+void Node::Inspect(int indent) {
+
+  if (this->children.size() > 0) {
+    for (int i = 0; i <= indent; i++) {
+      std::cout << "\t";
+    }
+    std::cout << "std::vector<Node> children: " << std::endl;
+  }
+
+  for (const auto &child : this->children) {
+    for (int i = 0; i <= indent; i++) {
+      std::cout << "\t";
+    }
+    child->Inspect(indent + 1);
+  }
+}

lib/node.h

@@ -0,0 +1,71 @@
+#ifndef NODE_H
+#define NODE_H
+
+#include <memory>
+#include <string>
+#include <vector>
+
+/// NOTE: What the heck are unique pointers (unique_ptrs)
+/// They are basically an abstraction over the typical (raw) pointer.
+/// They handle ownership and deletion of the pointer for us, to prevent memory
+/// leaks.
+/// They are pretty easy to use, and only need to exist in places where new ones
+/// are created. i.e., functions should not accept unique_ptrs, instead they
+/// should accept normal pointers or references.
+/// When calling a function that accepts a raw pointer, the unique_ptrs.get()
+/// method is required. When calling a function that accepts a reference, the
+/// reference operator (*) works perfectly fine. Hence, in this project we will
+/// try to avoid using raw pointers, and only use references when needed.
+
+// NOTE ABC
+class Node {
+protected:
+  /**
+   * @brief List of children nodes.
+   *
+   * Most nodes will not have children, but some may, therefore this class must
+   * have it.
+   *
+   * @author Hayden Hargreaves (hhargreaves2006@gmail.com)
+   */
+  std::vector<std::unique_ptr<Node>> children;
+
+public:
+  /**
+   * @brief Inspect (view) the contents of the Node.
+   *
+   * This is a recursive approach to allow for indentation for easier viewing.
+   *
+   * @author Hayden Hargreaves (hhargreaves2006@gmail.com)
+   */
+  virtual void Inspect(int indent = 0);
+
+  /**
+   * @brief Return the node as a string.
+   *
+   * In this ABC the content is just returned with no modifications. The child
+   * nodes are expected to modify this behavior. i.e. wrapping in HTML tags.
+   *
+   * @author Hayden Hargreaves (hhargreaves2006@gmail.com)
+   */
+  virtual std::string ToHtml() const = 0;
+
+  virtual void AddChild(std::unique_ptr<Node> child) {
+    // Move ownership from the existing owner, to this class
+    this->children.push_back(std::move(child));
+  }
+
+  /**
+   * @brief Return a read-only (const) list of children.
+   *
+   * Return our list of unique ptrs, they are const and therefore only have read
+   * access.
+   *
+   * @author Hayden Hargreaves (hhargreaves2006@gmail.com)
+   */
+  virtual const std::vector<std::unique_ptr<Node>> &GetChilren() const {
+    return this->children;
+  }
+};
+
+#endif