Directformal

Directformal, often stylized as directFormal, is a term used in formal methods to describe a class of approaches and tools that prioritize direct reasoning about a system's behavior from a formal specification using a direct proof calculus. Unlike workflows that rely on multiple intermediate models, directFormal aims to minimize translation steps and maintain a tight correspondence between specification and verification results.

Core concepts include a domain-specific language for specifying state machines, data types, and properties; a direct proof engine implementing a calculus that supports both automatic proof search and interactive proof development; modular proof composition through lemma decomposition; and interoperability with existing verification ecosystems through export/import of intermediate representations where applicable.

In practice, directFormal tools are applied to software and hardware verification, safety-critical systems, and protocol analysis. Typical workflows involve writing a formal specification in the DSL, issuing direct proofs of specified properties, and iteratively refining the model to address counterexamples provided by the proof engine or counterexample generators.

The landscape is diverse, with multiple research and commercial implementations offering differing syntax and semantics. The approach has been discussed as a way to improve traceability and reduce verification effort, though it also faces challenges such as learning curves, scalability, and integration with legacy toolchains.

Related concepts include formal verification, theorem proving, direct proof methods, and model checking.