The Design, Evolution, and Use of KernelF An Extensible and Embeddable Functional Language

• Published in: Theory and Practice of Model Transformation pp. 3 - 55
• Main Author: Voelter, Markus
• Format: Book Chapter
• Language: English
• Published: Cham Springer International Publishing 2018
• Series: Lecture Notes in Computer Science
• Subjects: Domain-specific languages; Functional Language; Language engineering; Language modularity; Meta programming
• ISBN: 9783319933160; 3319933167
• ISSN: 0302-9743; 1611-3349
• DOI: 10.1007/978-3-319-93317-7_1

KernelF is a functional language built on top of MPS. It is designed to be highly extensible and embeddable in order to support its use at the core of domain-specific languages, realising an approach we sometimes call Funclerative Programming. “Funclerative” is of course a mash-up of “functional” and “declarative” and refers to the idea of using functional programming in the small, and declarative language constructs for the larger-scale, often domain-specific, structures in a program. We have used KernelF in a wide range of languages including health and medicine, insurance contract definition, security analysis, salary calculations, smart contracts and language-definition. In this paper, I illustrate the evolution of KernelF over the last two years. I discuss requirements on the language, and how those drove design decisions. I showcase a couple of the DSLs we built on top of KernelF to explain how MPS was used to enable the necessary language modularity. I demonstrate how we have integrated the Z3 solver to verify some aspects of programs. I present the architecture we have used to use KernelF-based DSLs in safety-critical environments. I close the keynote with an outlook on how KernelF might evolve in the future, and point out a few challenges for which we don’t yet have good solutions.