Program generation has been successful in generating high-performance code in highly modular way. Yet, programming-language supports for program generation needs further improvement. One important omission is the functionality of generating modules in a type safe way. Inoue et al. have addressed this issue in 2016, but investigated only a few examples. We propose a language as an extension of (small subset of) MetaOCaml in which one can manipulate and generate code of modules, and implement it based on a simple translation to an existing language. We show that our language solves the performance problem in functor applications and that it provides a suitable basis of hand-written custom code generators for modules.