  Quantum software plays a critical role in exploiting the full potential of
quantum computing systems. As a result, it is drawing increasing attention
recently. As research in quantum programming reaches maturity with a number of
active research and practical products, software metric researchers need to
focus on this new paradigm to evaluate it rigorously and quantitatively. As the
first step, this paper proposes some basic metrics for quantum software, which
mainly focus on measuring the size and structure of quantum software. These
metrics are defined at different abstraction levels to represent various size
and structure attributes in quantum software explicitly. The proposed metrics
can be used to evaluate quantum software from various viewpoints.
