private:
void append(const std::string &);
void append(char);
void set_source(unsigned, unsigned);
public:
private:
void append(const std::string &);
void append(char);
void set_source(unsigned, unsigned);
public:
virtual void visit(Block &);
virtual void visit(Literal &);
virtual void visit(ParenthesizedExpression &);
virtual void visit(Block &);
virtual void visit(Literal &);
virtual void visit(ParenthesizedExpression &);