Xavier Leroy (born 1968) is a French computer scientist known for creating OCaml and CompCert. His work demonstrates that programming language research can produce both elegant theory and practical tools used in industry.
OCaml Development
At INRIA, Leroy led the development of OCaml, combining ML’s type system with efficient native code compilation and object-oriented features. OCaml proved that functional programming could be performant enough for production use.
CompCert
Leroy’s most celebrated achievement is CompCert, a C compiler proven correct using the Coq proof assistant. The project took years and showed that verified compilation—once thought impractical—could work for a real programming language.
Contributions to Theory
Leroy has made theoretical contributions including:
- Modular type systems for modules and functors
- Certified compilation techniques
- Semantics of programming languages
- Proof engineering methods
Recognition
Leroy was elected to the Collège de France, one of France’s highest academic honors, for his contributions to computer science. He has received numerous awards for his work on programming languages and formal methods.
Philosophy
Leroy emphasizes the connection between theory and practice. CompCert demonstrates that formal methods can produce not just proofs but useful software. His work shows that the divide between academic research and practical programming can be bridged.