1 files changed, 12 insertions, 2 deletions
diff --git a/src/tuplr.hpp b/src/tuplr.hpp
index de025b7..5deff71 100644
--- a/src/tuplr.hpp
+++ b/src/tuplr.hpp
@@ -61,11 +61,21 @@ struct Error {
 	string msg;
 };
 
-/// Expression ::= Atom | (SubExp*)
+/// Expression ::= Atom | (Expression*)
 template<typename Atom>
-struct Exp : public std::vector< Exp<Atom> > {
+struct Exp : private std::vector< Exp<Atom> > {
 	Exp(Cursor c)                : type(LIST), loc(c)          {}
 	Exp(Cursor c, const Atom& a) : type(ATOM), loc(c), atom(a) {}
+
+	void push_back(const Exp<Atom>& exp) { vector< Exp<Atom> >::push_back(exp); }
+
+	bool             empty() const { return vector< Exp<Atom> >::empty(); }
+	const Exp<Atom>& front() const { return vector< Exp<Atom> >::front(); }
+
+	typedef typename vector< Exp<Atom> >::const_iterator const_iterator;
+	const_iterator begin() const { return vector< Exp<Atom> >::begin(); }
+	const_iterator end()   const { return vector< Exp<Atom> >::end(); }
+
 	enum { ATOM, LIST } type;
 	Cursor              loc;
 	Atom                atom;