WIP: Generating Sequence Diagrams for Modern Fortran

Fortran finds widespread use in scientific and engineering communities that embraced computing early, including weather and climate science and mechanical, nuclear, and aerospace engineering. Over its lifetime, Fortran has evolved to support multiple programming paradigms, including Object-Oriented Programming (OOP). Despite the recently burgeoning ecosystem of tools and libraries supporting modern Fortran, there remains limited support for generating common Object-Oriented Design (OOD) diagrams from Fortran source code. ForUML partially fills this need by reverse engineering Unified Modeling Language (UML) class diagrams from object-oriented (OO) Fortran programs. Class diagrams provide useful information about class structures and inter-relationships, but class diagrams do not convey the temporal information required to understand runtime class behavior and interactions. UML sequence diagrams provide such important algorithmic details. This paper proposes to extend ForUML to extract UML sequence diagrams from Fortran code and to offer this capability via a widely used open-source platform. The paper argues that the proposed capability can raise the level of abstraction at which the computational science community discusses modern Fortran.