parser.cpp

class ExpressionAST {
public:
    virtual ~ExpressionAST() {}
};

// Function call
class FunctionCallAST : public ExpressionAST {
    std::string m_callee;
    std::vector<std::unique_ptr<ExpressionAST> > m_arguments;
public:
    FunctionCallAST(
            const std::string &callee,
            std::vector<std::unique_ptr<ExpressionAST> > arguments) :
            m_callee(callee), m_arguments(std::move(arguments)) {}
};