134 lines
2.7 KiB
C++
134 lines
2.7 KiB
C++
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#include <optional>
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#include <string>
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#include <vector>
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#include <filesystem>
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/// Port of tree.py to C++
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template<class T>
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struct Tree {
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// FIXME make T not require default constructability
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struct Node {
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protected:
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friend Tree;
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Node* parent = nullptr;
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std::vector<Node*> children{};
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T item{};
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public:
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~Node() {
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for(auto& child: children)
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delete child;
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}
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T& data() {
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return item;
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}
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const T& data() const {
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return item;
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}
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bool is_leaf() const {
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return children.size() == 0;
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}
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Node* create_leaf(const T& item) {
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auto* node = new Node;
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node->parent = this;
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node->item = item;
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children.push_back(node);
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return node;
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}
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template<class Fn>
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void walk(Fn&& fn) {
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fn(this);
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if(!is_leaf()) {
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for(auto& child: children)
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child->walk(fn);
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}
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}
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template<class Pred>
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std::optional<Node*> find_child(Pred&& predicate) {
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if(predicate(*this))
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return this;
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for(auto& child: children)
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if(predicate(*child))
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return child;
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return std::nullopt;
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}
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std::size_t parent_count() const {
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auto* parent = this->parent;
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auto parent_count = 0z;
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while(parent) {
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parent_count ++;
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parent = parent->parent;
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}
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return parent_count;
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}
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};
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Tree() {
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root = new Node;
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}
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~Tree() {
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delete root;
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}
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// Trees are not copyable but they can move
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Tree(const Tree&) = delete;
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Tree(Tree&&) = default;
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template<class Fn>
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void walk(Fn&& fn) {
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root->walk(fn);
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}
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Node* create_leaf(const T& item) {
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return root->create_leaf(item);
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}
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private:
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Node* root;
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};
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void test_tree() {
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Tree<std::string> tree;
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auto* virus = tree.create_leaf("Virus");
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auto* worm = tree.create_leaf("Worm");
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auto* test = virus->create_leaf("test");
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test->create_leaf("a");
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test->create_leaf("b");
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test->create_leaf("c");
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test->create_leaf("884");
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tree.walk([](auto* node) {
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auto tab_count = node->parent_count();
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auto& data = node->data();
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for(auto i = 0; i < tab_count; ++i)
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std::printf("\t");
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if(data.empty()) {
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std::printf("(root)\n");
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} else {
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std::printf("%s\n", data.c_str());
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}
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});
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}
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int main() {
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test_tree();
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return 0;
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}
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