/// A node in a syntax tree. Each node is either a Leaf (representing tokens) or
/// a Tree (representing language constructrs).
class Node {
-public:
+protected:
/// Newly created nodes are detached from a tree, parent and sibling links are
/// set when the node is added as a child to another one.
Node(NodeKind Kind);
+ /// Nodes are allocated on Arenas; the destructor is never called.
+ ~Node() = default;
+
+public:
+ /// Nodes cannot simply be copied without violating tree invariants.
+ Node(const Node &) = delete;
+ Node &operator=(const Node &) = delete;
+ /// Idiomatically, nodes are allocated on an Arena and never moved.
+ Node(Node &&) = delete;
+ Node &operator=(Node &&) = delete;
NodeKind getKind() const { return static_cast<NodeKind>(Kind); }
NodeRole getRole() const { return static_cast<NodeRole>(Role); }
/// A node that has children and represents a syntactic language construct.
class Tree : public Node {
public:
- using Node::Node;
static bool classof(const Node *N);
Node *getFirstChild() { return FirstChild; }
}
protected:
+ using Node::Node;
/// Find the first node with a corresponding role.
Node *findChild(NodeRole R);