1 files changed, 3 insertions, 1 deletions
diff --git a/src/node.hh b/src/node.hh
index 919d013..992721c 100644
--- a/src/node.hh
+++ b/src/node.hh
@@ -44,8 +44,10 @@ using node_set =
 
 class stringable {
 public:
+  stringable();
+  explicit stringable(const stringable &);
+  virtual ~stringable();
   [[nodiscard]] virtual auto string() const -> std::string = 0;
-  virtual ~stringable() = default;
 };
 
 class variable : stringable {