FPP: A Modeling Language for F Prime

We present F Prime Prime (FPP), a new open-source
modeling language for F Prime. F Prime is an open-source
flight software framework developed at JPL and deployed,
among other places, on the Mars helicopter Ingenuity. FPP
provides a convenient way to model the architectural elements
of an F Prime application, e.g., components, ports, and their
connections. It has a succinct and readable syntax, a well-
defined semantics, and robust error checking and reporting. The
FPP tool suite, written in Scala, analyzes FPP models, reports
errors, and translates correct FPP models to a combination
of XML and C++. Existing F Prime tools translate the XML
to a partial implementation in C++, to be completed by the
developers. The model elements have clean interfaces and are
highly reusable. An accompanying visualization tool constructs
diagrams of components and connections that FSW developers
can use to understand and communicate their designs, for ex-
ample at reviews. We discuss the design and implementation of
FPP and the integration of FPP into F Prime. We also discuss
our experience using FPP to construct F Prime models. Finally,
we discuss our plans for future work, including improved code
generation, improved visualization, and more advanced analysis
capabilities.