Use cases are a practically proven choice to concisely and precisely express what highly interactive systems do. Several attempts have been made to modularize code according to use cases. None of these approaches is able to gather all the code related to a use case in one module and to reflect its steps. However, to allow for code to be modularized according to use case flows and their steps, an instrumentation environment is necessary. In this paper, literal multi-language use case coding based on defragmentation is proposed. The approach aims at fully preserving use case flows in as comprehensible form as possible. The steps of use case flows appear directly in the code as comments. Despite being comments, the steps are active, which is achieved by a dedicated preprocessor and framework. The detailed step implementation gathers all the code fragments of each step each of which may be in a different programming language.