PROMELA is not a programming language. PROMELA is a language for building verification models. As a result of this specialization, PROMELA contains many features that are not found in mainstream programming languages. These features are intended to facilitate the construction of high-level models of distributed systems. Gerard Holzmann provides an overview in this chapter from his book, “The SPIN Model Checker: Primer and Reference Manual.”
It’s great to see formal verification methods getting some press! Very important stuff for mission critical systems and security sensitive applications.