  The evaluation of Natural Language Generation (NLG) models has gained
increased attention, urging the development of metrics that evaluate various
aspects of generated text. LUNA addresses this challenge by introducing a
unified interface for 20 NLG evaluation metrics. These metrics are categorized
based on their reference-dependence and the type of text representation they
employ, from string-based n-gram overlap to the utilization of static
embeddings and pre-trained language models.
  The straightforward design of LUNA allows for easy extension with novel
metrics, requiring just a few lines of code. LUNA offers a user-friendly tool
for evaluating generated texts.
