node_impl.cc

#include <functional>
#include <initializer_list>
#include <optional>
#include <string>
#include <vector>

// A single node of our parse tree.
class Node {
 public:
  // Construct a node using a list of triggers.
  explicit Node(std::initializer_list<std::string> triggers)
      : triggers_(triggers) {}

  // Destruct owned memory.
  ~Node() {
    for (auto node_ptr : nodes_) {
      delete node_ptr;
    }
  }

  // Append a node to this node.
  void add_node(Node *node) { nodes_.push_back(std::move(node)); }

  // Give this node an action.
  void set_action(std::function<void()> func) { action_ = std::optional(func); }

 private:
  // Trigger words for this node.
  std::vector<std::string> triggers_;

  // Sub-nodes.
  std::vector<Node *> nodes_;

  // Optional action. A leaf node will have a non-empty action.
  std::optional<std::function<void()>> action_ = std::nullopt;
};